Monthly Archives: May 2022

Would you rent or subscribe for clean air?

Would you rent or subscribe for

clean air?

Ok, I’ve heard of all kinds of rentals and subscription plans. But, air is public domain, right?  How on earth does such a subscription get delivered?  Certain companies have air purifier machines that can be rented by the day or week, etc., which can be really helpful if you only need the equipment for a short time. 

Vacations:  Personally, I think the vacation rental option here is brilliant–how many times have you gone on vacation or to a conference, and the hotel room seems musty (of course, this happens in a hotel that is fully booked with no way to change rooms)?  Here are some options for renting air purifiers to trap the contaminants in the air while you work or play:

  •  This company rents a premium air purifier for only $15 a day in the Orange County area, with the option to upgrade to a medical grade filter for only $5 per day more.  They have many more baby products, as well as more pickup and delivery locations in the US.  They can deliver to airports and car rental places, making it easy to pick up an air purifier and have a great vacation with or without little ones!
  • Lyft has teamed up with Wynd, an air purifier company, to add an air purifier option to rental cars.  At only $15 per day, you can add a Wynd purifier to your rental to get out those odors and unseen germs that cleaning did not remove.   If you plan on doing a lot of driving on your next trip, it’s worth checking out!

For parties and indoor events: 

  • Sunbelt Rentals Portable Air Scrubbers:  This company has a large selection of units for many different uses–light commercial or residential units, medical grade, odor removal–you name it!  They had a super-fast response when I emailed for more rental info.  Their S-, M-, and L-Light purifiers feature H13 true HEPA and carbon filters.  The filters for these machines cost extra, but in general, the rental prices are very reasonable ($17-53 per day in the Orange County area). 

For remediation jobs (like moving into a house that had noxious pet or smoke odors, or remediating mold damaged areas):

  • Home Depot Dri-Eaz HEPA Air Scrubber:  Near our Orange County, California location, there are several stores that have this machine, which will purify a 1000 square foot space with up to 500 cubic feet per minute air flow.  The carbon and HEPA filters are included for $159 per day or $318 per week.  (After this point, you would be better off buying one!)
  • The same scrubber from Home Depot rents for less in Petaluma and San Rafael, CA from CalWest Rentals ($70 per day or $250 per week).

If you don’t live in California, try searching for “air purifiers for rent near me”.  Admittedly, renting purifiers is more expensive than buying them in the long run.  But if you have a trip, project, an event, or some other short-term need for clean air, you have options!

Do you need a really large quantity of clean air?  Enter pulsed electromagnetic field radiation, which has actually been around for a while.  It’s similar to wi-fi or the systems used by cellphone services.  It is broadcasted in short pulses and has been used since the early 1990’s in wastewater treatment applications.  The pulses of RF energy contact small particles in the air (it actually works best on particles less than 20 nm) and increases their negative charge, to accelerate the particles grouping together and falling out of the air.  These small particles will settle as dust, which if inside a building can be vacuumed, or if outside will be absorbed into the earth’s natural soil.

Devic-Earth is a company based in India that has designed a Clean Air Subscription, which utilizes their unique equipment under the name of “Pure Skies”.  Companies such as heavy industry, cities, or event halls can subscribe continuously or for only a month, depending on their needs. The process claims to  improve air quality by 33-90% over large areas at the lowest cost per unit area.   The equipment is usually installed in a matter of hours and can cover spaces inside with a minimum of 20,000 ft2 or outside with a minimum of 5 acres.  What’s most interesting is the way this technology can overcome many types of air pollution for organizations that had no control over pollution previously.  For example, one testimonial stated that the equipment was employed that Delhi (India) half-marathon in 2018, and another 25K (Tata Steel Kolkata) to achieve results of 30-54% improvements.  The results are measured from before the equipment is turned on, and monitored throughout deployment, by an air quality monitor.  The studies and testimonials also report the presence of rain, which can also drastically reduce air pollution because it causes particles to fall to the ground with the rain. 

This particular provider assures the safety of its equipment/process because it uses “ISM frequency band similar to the Wi-Fi spectrum (2.4-2.5 GHz) and power levels are maintained under standard regulations.”   The dangers of Wi-Fi are not generally agreed upon, with many governments and organizations taking the stance that Wi-Fi is safe, such as Canada.  Many studies are like this one, however: they have found that non-thermal EMF exposures have major impacts “on both of the most important intercellular regulatory systems in the body, the nervous system and the endocrine systems…major impacts on what may be the most important intracellular regulatory system, the calcium regulatory system… we also have non-thermal EMFs attacking the DNA of our cells, putting our biological inheritance at great risk. As living organisms, EMFs attack each of the most important functions that go to the heart of our human complexities.”  

I did note that on Devic-Earth’s website, the company claims that “Pulsed radio waves are periodic bursts of radio waves or radio frequency energy (RF). The pattern of these bursts depends on the desired effect.  This is unlike the radio wave transmission from telecommunications equipment such as Wi-Fi or mobile towers which are usually continuous in nature.” 

Wi-Fi by nature is a pulsed system.  The previously referenced study notes that “pulsed EMFs are usually much more biologically active than are non-pulsed (also known as continuous wave) EMFs of identical frequency and similar average intensity (study references from years 1965-2015). This pattern of action is particularly important because all wireless communication devices, including Wi-Fi (2015 studies) communicate via pulsations and are likely to be particularly dangerous as consequence of this. (One 2015 study) have argued that the more pulsed they are, the more damaging EMFs will be and while this may still be questioned, it may well be a roughly applicable generalization. It is also true that artificial EMFs are polarized and this makes artificial EMFs particularly dangerous (2005 and 2015 studies). Polarized EMFs put much larger forces of electrically charged chemical groups than do non-polarized EMFs (2015 study)”.  Because of their statement of being different from Wi-Fi, Devic-Earth’s Pure Skies may be at a slower pulse in comparison to Wi-Fi.  It’s not known if this pulse is less or more detrimental than Wi-Fi to cells and our nervous and endocrine system and DNA.  Most people are unaware of this potential damage and as such, don’t have a problem working and living in Wi-Fi zones (it’s a welcomed convenience), so that Pure Skies technology would probably also be acceptable and welcomed by most people.  It may not even need to be disclosed in many places.

Whether by filter, EMF or other technology, now I know you can rent clean air for your room, house, car, convention center or even an outdoor event!

Testing out TotalClean: a breath of fresh air for anyone who cleans

Testing out TotalClean: a breath of fresh air for anyone who cleans

TotalClean is our new powerhouse non-toxic cleaner and I’m very impressed!  Since it’s non-toxic to humans and pets and safe for most surfaces, there are unlimited uses for it in the home.  

Here's some helpful facts about it:

  • You can use the pre-mixed 32 oz. spray bottle, or mix your own with the concentrate.  When mixing your own, I found it was useful to have several empty spray bottles available in plastic or glass (your preference) to make various strengths and keep them available (for instance, keep a spray bottle and some paper towels in the bathroom for deodorizing and cleaning whenever needed!) 
  • TotalClean has no smell, yet it deodorizes the air and surfaces by eliminating odorous bacteria on contact.  
  • TotalClean does not lose its effectiveness over time, unlike cleaners such as hydrogen peroxide and hypochlorous acid.
  • TotalClean is safe to mix with other natural and non-toxic ingredients such as vinegar, baking soda or hydrogen peroxide to boost its efficacy.  For instance, I have a white synthetic cloth shower curtain that gets pink mildew around the hem after several months.  It's not super-easy to take down, so I used to soak the hem in a small container of bleach water to brighten it.  I had to leave the exhaust fan for over 4 hours until it dried!  This time, I used normal strength TotalClean mixed with 1/2 cup hydrogen peroxide, and the pink disappeared as if I had used bleach, with no smell or toxic fumes!  Here are the before and after photos:

  • The industrial formulation for TotalClean is used in many wastewater treatment plants around the country, so we know it's safe for city wastewater and home septic systems.

Check out our video on getting started with the concentrate and keep reading to learn about its many uses!

Normal strength: that which comes pre-mixed in the 32oz. spray bottle (1:7 parts TotalClean to water)

  • Windows and mirrors: For nice streak-free cleaning, spray the surface with TotalClean and use newspaper to wipe dry.  If mixing TotalClean from concentrate, using distilled water or zerowater leaves less residue/streaks because no minerals from the water remain on the glass.
  • Counters: Spray non-greasy stone, tile, and wood countertops with TotalClean and wipe dry with a paper towel or clean cloth.  For greasy countertops, see concentrate solutions below.
  • Bathroom sinks: Cleans off toothpaste spatters and dust easily
  • Cabinets (except greasy cabinets: see concentrate below): spray and wipe with a clean cloth
  • Dishwasher: White vinegar is highly acidic and although it cleans, it can damage gaskets and seals if used straight from the bottle. You can use TotalClean safely (even in concentrate form!) on all exterior and interior parts of a dishwasher including: door gaskets, filters, spray arms, drain, and anywhere visible food/waste buildup shows.
  • Refrigerator: You can wipe down the exterior, interior and door seals with TotalClean, with no need to rinse unless you have a lot of food particles.  I loved the fact that I could clean shelf by shelf as I had the time, without the hassle of unloading the whole fridge for fear of contamination (as with toxic cleaners containing bleach).  Spray TotalClean on hard or sticky spills, wait a few minutes for it to soften, and wipe away.  Here is an example of before spraying and after spraying (not even wiping):

  • Floors: Use this normal strength ratio (1 part TotalClean to 7 parts hot or warm water) to get tile and ceramic floors really clean!  If you have sealed wood floors, TotalClean is also a safe substitute for any water-based cleaner (just make sure to wring out your mop well and not flood the floor). 
  • Laundry deodorizing: spray-soak extra-stinky clothing items with TotalClean before washing.  See note at end of post regarding optical brightening. 
  • Shoes: Spray material and allow to soak for 30 min before washing in water and dish detergent and rinsing thoroughly, to kill odors
  • Washing Machine cleaner: spray the seals and wipe on front-loading machines to keep them free of mold and mildew, and spray and wipe exterior surfaces to remove dust and laundry detergent
  • Dusting: Make your dustcloth damp with TotalClean and wipe away dust
  • Deodorizing: spray TotalClean into the air in and around kitchen garbage, pet litter trays, bathrooms, laundry rooms, into shoes, and anywhere odors linger
  • Carpet cleaning: mist TotalClean lightly onto carpets, allow to dry, and vacuum. For deep cleaning, use this solution in a carpet cleaning machine and be sure to vacuum thoroughly to remove moisture. 
  • Cleaning mold from tile grout: Since grout is porous, if possible start with dry grout so that it will absorb TotalClean deep into the grout.  Spray-soak the area and wait 5 minutes, then scrub with an old toothbrush or stiff brush and flush with water.  If this does not remove stains, go to the concentrate (see below)
  • Car interiors: Dampen a cloth with TotalClean and wipe over dashboards, gauges and any solid surface, as well as vinyl or leather seats.   To freshen/clean upholstery and carpets, spray onto surface and use a wet-dry vacuum to remove moisture, or use TotalClean in an upholstery cleaning machine instead of toxic commercial cleaners (see our post on How to Clean your car’s interior to keep away mold)
  • Cleaning mildew from exterior siding: Spray on mildew, wipe with a soft brush or rag, and spray with water to rinse clean. Here are some before and after photos of painted wood siding using minimal effort (I used a carwash brush, and in the 2nd photo you can see some of the untouched surface on the left side):

Uses for Concentrate:

Double (1:3 parts TotalClean to water):

  • For deep carpet cleaning, use TotalClean at 1:3 or 1:1 ratio of cleaner to water in a carpet cleaning machine and be sure to vacuum thoroughly to remove moisture.  If using a wet-dry vacuum, spray the carpet with this solution using a spray bottle, agitate with a stiff brush (if it does not damage carpet) and vacuum out with the wet-dry vac.

Two to One: (2:1 parts TotalClean to water)

  • Degreasing countertops: Grease spatters will wipe clean quickly with this solution.

Full-strength concentrate: 

  • Cleaning greasy kitchen cabinets: The cabinets above cookstoves can get very tacky with residue from cooking oil vapors.  I found that full-strength concentrate will take off the tackiness and restore the smooth finish on the cabinets above my stove.  Use it in a spray bottle and wipe with clean towel or paper towel.
  • Cleaning deeply stained mold areas from tile grout: Since grout is porous, if possible start with dry grout so that it will absorb TotalClean deep into the grout.  Soak the area and wait 10 minutes, then scrub with an old toothbrush or stiff brush and flush with water.  

What else do you think it can do?  If you have a specific question or comment about using TotalClean, contact us!

Photo by Daiga Ellaby on Unsplash

Increasing our bodies’ resistance to mold–naturally

Increasing our bodies’ resistance to mold--naturally

There's no "silver bullet", but regarding exposure to mold, there’s a lot we can control, like humidity, water leaks that can be stopped and remediated, air purifiers, etc. Sometimes, though, there are things we just can’t control, like having a new work assignment in a moldy area, or having a scrape (literally) that infects us with mold.   That’s what happened to a young man traveling in Costa Rica, who developed a lesion in his brain due to a type of black mold after scraping his arm on a bike ride.  In India, doctors are facing an unprecedented spike in mucormycosis, an infection from another type of mold species that is very prevalent in the hot, humid country.  Indiscriminate use of steroids to stop inflammation from the virus that caused COVID-19 causes some patients to have weakened immune systems, making them susceptible to infestation of Mucorales, the group of fungi that includes molds responsible for mucormycosis. (Science News)  With Mucorales, the fungi tend to thrive in diabetics because of elevated blood sugar levels, which turn the blood more acidic, creating an ideal environment for it to spread.  Unfortunately, the virus that causes COVID-19 also damages the beta cell of the pancreas, decreasing insulin production needed to check high blood sugar.   

It doesn’t need to be far from home, as this can happen in your backyard.  Candida auris has been identified as a new global threat; it’s a type of fungus that is resistant to 2 out of 3 classes of antifungal drugs.  

Here is what we’re seeing cause susceptibility to fungi:

  • Steroid medications, including artificial corticosteroids, which dampen immune function by lowering the number of lymphocytes 
  • Stress releases natural corticosteroid in our bodies (decreasing immune function as above) and stress also alters a number of bodily functions like digestion activity, blood pressure, blood cholesterol levels, all of which lead to an increased risk of disease (
  • High blood sugar from diet, disease or inadequate medication management
  • Other causes of more acidic blood: respiratory acidosis is the body’s response to having too much carbon dioxide in the blood (a common cause would be sleep apnea), metabolic acidosis which includes ketoacidosis, lactic acidosis, renal tubular acidosis and hyperchloremic acidosis (webMD)
  • Pre-existing conditions such as AIDS: “According to the Centers for Disease Control and Prevention (CDC), fungi are among the leading causes of opportunistic infections affecting patients with HIV/AIDS [16].” (study)

The good news is that fungi have weaknesses we can exploit.  Here are some of them:

  1. Copper: fungus has a small window of tolerable copper levels.  “the human immune system utilizes both copper toxicity and copper starvation in responding to fungal infections. “(Valeria Culotta, PhD) Drinking water stored in copper vessels may provide the excess copper needed to kill many pathogens (
  2. Iodine: A lack of iodine has been shown to cause many different diseases and symptoms, including endemic goiter, hypothyroidism, cretinism, decreased fertility rate, increased infant mortality, and mental retardation (article). On the other hand, iodine has been shown to cure toenail fungus (study), and iodine is is rapidly effective against viruses, bacteria (both Gram negative and Gram positive), fungi and spores( However, not all iodine preparations have high- germicidal properties.  Molecular iodine (I2) is the form that kills fungus and molds most quickly. Here are the positives about a new formulation of iodine, ioRinse
  • Does not stain, unlike previous formulations of povidone-iodine
  • does not induce resistance development in targeted microorganisms
  • substantivity (ongoing residual effect) of iodine for up to 72 hours is well documented.
  • Safe for chronic use as a mouthwash
  • Affordable
  • Molecular iodine is also available in a Nasal Spray (ioMist) to protect sinus passages.
  1. Zinc is a metal that is needed for a healthy body and immune system, but it can be stolen by pathogenic fungi such as mold.  Our bodies attempt to withhold this essential vitamin from pathogens (a process called nutritional immunity), but certain pathogens have evolved highly sophisticated methods of acquiring it from hosts anyway. (study)  A 2017 US study carried out over six weeks found that taking just 4mg extra of zinc a day made a major difference to the health of cells, which in turn makes your body better able to fight infections and diseases. The team concluded that zinc reduces ‘oxidative stress and damage to DNA’ that helps protect against chronic diseases.
  1. Glutathione: When our bodies are exposed to harmful fungus, they increase production of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS).  ROS/RNS are helpful in that they signal an invasion of the body and trigger more immune responses, but they also can damage lipids, proteins and DNA (study), and overwhelm the natural antioxidant capacity of our cells, causing the imbalance that is known as oxidative stress. Normally ROS levels are kept in balance with antioxidants in our cells, which is known as cell redox homeostasis, but in the presence of pathogens, ROS increases dramatically, causing inflammation and other potentially damaging symptoms.  Glutathione (GSH), made of the three amino acids cysteine, glutamate, and glycine, is an important antioxidant in our bodies (  Our glutathione levels decrease naturally as we get older, but more acutely during diseases such as cancer, HIV, or Parkinson’s disease.  In a Korean study, it was shown that glutathione significantly increased a cell’s chances of surviving exposure to large amounts of ROS like hydrogen peroxide (H2O2).  Low levels of glutathione peroxidase are also coincident with conditions like vitiligo, multiple sclerosis, and Type 2 diabetes. (  Therefore, supplementing with this “superhero” antioxidant can significantly improve our outcome when faced with mycotoxins.  Here are some ways to supplement:
  • Intravenous (IV) glutathione is the quickest and most effective form of supplementation, but its availability to the public is limited.  
  • Although many companies offer glutathione in oral form, it’s generally not effective in raising free glutathione in the blood because digestive enzymes break it down into its three components.  Therefore,  two alternative forms of glutathione that translate to higher glutathione levels in the blood:
    • liposome-encapsulated glutathione, or
    • s-acetyl glutathione: this has been shown to have similar results to IV glutathione (  
  • Whey protein contains free fatty acids that actually inhibit growth of C. albicans (study). C. albicans is the most prevalent form of fungal infections in people (, and knowing this, supplementation with a whey protein from grass-fed cows can be a good way to increase resistance to certain fungi (  
  1. Iron: Iron is essential for both humans to grow.  Iron is needed to produce red blood cells and hormones, as well as maintain our immune system response, particularly a level of lymphocytes (scientific article). Here is the conundrum however: fungus also needs iron, and will steal iron from our bodies or scavenge excess iron if it is supplemented.  In healthy people, iron supplements are a good way to make sure we have the iron we need.  (If normal iron supplements upset your stomach, try a “slow-release” formula). However, if you are diabetic, undergoing chemotherapy, or have any other major illness, you may want to consult your doctor before adding an iron supplement, to make sure that it does not feed an invasive pathogen like mucorales, which is particularly disfiguring and deadly in immune-compromised patients. 
  2. Healthy gut:  According to, “A healthy gut contains healthy bacteria and immune cells that ward off infectious agents like bacteria, viruses and fungi.” In addition, a healthy gut microbiome trains immune cells for guarding the brain:  scientists have discovered that certain plasma cells from the intestines migrate to the brain, where they stand guard to release IgA antibodies to block the entry of pathogens to the brain. (Science News)  How to maintain a healthy gut?  This article discusses some excellent ways to maintain a healthy gut microbiome. 
  3. Getting adequate sleep: During sleep, our bodies produce cytokines and T-cells, both of which are important to our immune response.  We’ve discussed how to get the most of your sleep time in a previous post, and this article from reviews the ways you can promote quality sleep.  

We’ve got the power to reduce the chance of acquiring nasty and life-threatening fungal infections, even in this world of ever-increasing dangerous microbes.  I hope this article gave you some new insights on some weapons in our immunity arsenal.

Photo by zibik on Unsplash

How to live with minimal AC and maximum ventilation

How to live with minimal AC and maximum ventilation

For decades (five to be exact), home design focus has been on sealing homes in order to reduce energy costs of heating and cooling.  Such energy efficiency has come at a price of air quality, because unlike, say, water, air cannot be “recycled” over and over without detriment.  Carbon dioxide concentrations will increase naturally just from breathing in and out, and toxins build up from emissions from the building itself and the products we use in it.  Humidity either builds up from water leaks and water use, or decreases from use of forced air heating.  

Is it time to advocate for more “leaky” homes?  Well, yes….but controlled leaks are key!  The leaks I’m talking about are ventilation with fresh air in a controlled way.

Here at HypoAir we often recommend adding more ventilation from outside to dilute the air in our homes, so it’s constantly on my mind: how do I get more ventilation during the hot months of the year?  We tell customers that it’s ok to open windows when the outside air is relatively clear of pollution, but many times it still has dust, pollen and smaller particles, so that presents a problem!

While researching this topic, I found a statement that sums up the problem:  

“Every new system installed today should have a Fresh Air Intake. It should not be optional, it should be mandatory. State laws do not force the issues, but health concerns do. Products that we use in our homes have Volatile Organic Compounds (VOCs) that put out gasses as they age. Without a Fresh Air Intake, these VOCs can build up and cause allergic reactions, asthmatic symptoms, and can require treatment with medicine to compensate for the contaminated air. The medical industry does not recognize contaminated air as a medical condition. The reason is, they can’t measure that when you go for treatment. They can only address the problem.

Generally, about 5-10% outside air is desirable. If you don’t have fresh air inside your system, should you add it? The answer is YES, especially if you're doing equipment replacement.” (Texas HVAC company)

Now, which new products aimed at cooling also increase ventilation?  I focused on whole home ventilation in a previous post; this one is more geared toward single-room or window units.

The EcoBreeze 2 is a smart window fan that takes outside air, filters it, and delivers it inside as clean, fresh air.  It has sensors: if the outdoor air is more hot or humid than indoors, then it shuts down and lets your A/C take over.  This is particularly useful in climates where outside ventilation is cool and dry, such as in the northern US. It retails for $229 and has optional MERV 13 filters for replacement (it comes with a MERV 8 filter).

Here’s what to do if you already have a window fan, in order to get cross-ventilation, which is very useful because with only 1 window fan, you’re not really cooling optimally unless you have another window open to allow the hotter air to escape.  

  1. On the hot or unshaded side of your home or room, install any standard window fan that you can seal effectively to your window, but set it to “exhaust” mode (pulling air out of the room).
  2. On the opposite (shaded) side of the home or room, install one of the following to pull cool air into the room through the filters, and exhaust it out through the fan.
    • Window Ventilation Filters  ($39.99-49.99, sizes accommodate windows from 20-44” wide).  These are optimal for smaller windows that don’t have any screens. 
    • Nanofiber PureAir Window Screens ($50 for 39” x 118”).  This window screen material is an upgraded version of insect screening; its tighter weave and electrostatic properties block much of the dust, pollen and pollution while still providing ventilation and maintaining your windows’ view.   Check out our article for how to easily swap out your insect screening with this revolutionary material!

Now, if your outside air is too hot or humid for adding a lot of ventilation, you can still use your window A/C in conjunction with a Window Ventilation Filter.  The window filter does not allow a lot of air to pass through (unlike a plain screen) but you can add the ventilation needed and let the AC do the cooling and dehumidification. 

If you want to replicate this on the scale of your whole house, many HVAC companies recommend QuietCool Whole House Fans.  I grew up with a whole house fan, but this one will not create a rumbling noise, so you can leave it running all night (hence its name).  Using Window Ventilation Filters or Nanofiber PureAir Window Screens in conjunction with the whole house fan will insure that your home is not filled with bugs, dust and pollen as it pulls in air from outside. What a relief to breathe in fresh air, especially while you sleep!

If any engineers out there are reading this, I’m still looking for:

  • a window heat pump unit (heating and cooling capacity)
  • with inverter technology (to save energy and provide constant temperature and humidity), and
  • a filtered ventilation component, like the EcoBreeze 2, and
  • a pollution monitor on the outside to shut off intake at times of high pollution   
  • Oh–and I like how new over-the-sill designs do not obstruct the window view.  

Am I asking too much?  I don’t think so–this is 2023–let us know what you come up with!

Photo by Olia Nayda on Unsplash

How to clean your car’s HVAC and interior to keep away mold!

How to clean your car’s HVAC and interior to keep away mold!

As I write this, we’re coming into another air conditioning season in the southeast US, which means air conditioning not only at home, but in your car.  Vehicles are so susceptible to mold ingress, because of where we drive (through dust, mud, and pollen), where they are parked (whether it’s outdoors in blazing hot driveways or indoors in damp garages), and their design (carpeting everywhere!  Air conditioning filters that hardly ever get changed!)  Whether or not you smell that musty moldy smell when you get in the car or turn on the A/C, now is the time to deal with mold before it deals with you.

Just like your home’s HVAC system, it’s important to maintain your car’s HVAC system for your health.  Here is a great article on cleaning the evaporator coils in your car.  This method is very non-invasive, and includes tips if any mold smells do not go away.   The antimicrobial agent they recommend is called Nutribiotic. Nutribiotic is a grapefruit seed extract (GSE) which is highly acidic and microbial at full concentration (be very careful mixing and using it!) but can be diluted to use as a coil cleaner.  Please note that using a commercial coil cleaner is not recommended because the residues can add many VOCs to the air you breathe, which may not go away for some time!  

When cleaning the HVAC system, be sure to replace the cabin air filter, which keeps a lot of dust and pollen out of the car.   Some older models don’t have a cabin air filter (commonly in pre-1996 vehicles and even as late as my 1999 Suburban), in which case you can even get creative and make one!  (For those of us who aren’t super-familiar with cars, note that the cabin air filter is different from the air intake filter.  The first one filters the air conditioning system, while the second one filters the air going into the engine, which is not what we’re talking about here.)

We’re working from top to bottom, and next come the seats.  Cloth seats will probably hold more dust and mold than vinyl or leather seats, because they are permeable and allow liquids and dust to pass through and stay in the foam beneath.  With any liquid cleaner you use, you should definitely use an extractor.  Whether it’s a carpet cleaning machine, or a simple wet-dry vacuum, you need a way to get the liquid back out of the carpet, or mold can set in after you just cleaned it!  If you live in a populated area, either one (carpet cleaner or wet/dry vac) should be available on places like Facebook marketplace for about $40. One more tip: only clean your car’s upholstery and carpet on a bright sunny day outside, or in a heated garage!  You’ll need the benefit of ventilation and heat to get the fibers completely dry. 

Now, what to use as a cleaner?  One of the most popular carpet cleaners in the supermarket is Resolve, and RESOLVE Professional Spot and Stain Carpet Cleaner earned an “F” grade from the Environmental Working Group (EWG), an organization dedicated to evaluating the safety of consumer products!  There is a better way. 

  • Our new Total Clean spray is like a Swiss Army knife that cleans solid and porous surfaces well!  Use it at normal strength (1:7 parts concentrate to water) for non-stained carpet and upholstery, or double or triple strength (1:3 or 1:1 parts concentrate to water) for stains.  Normal strength TotalClean is great for vinyl and leather surfaces, as well as any hard surfaces such as dashboards, gauges and steering wheels, being sure to wipe it away quickly with a clean dry towel. 
  • Most “homemade” carpet cleaners call for a mixture of vinegar, baking soda and water in various proportions.  I really like this one, which adds in (non-toxic) dish soap.  If you are using a simple wet-dry vacuum, use the cleaner in a spray bottle, agitate any problem areas or stains with a scrub brush, and follow with the vacuum to get the liquid out.  If you are using the carpet cleaner machine, follow manufacturer’s directions.  In either case, make sure to use the liquid sparingly!  Too much liquid going in (especially on cushioned areas) increases the likelihood that it will not all come out with the vacuum.  I advise taking out a car mat to clean first, to assess the suction power of your vacuum or cleaning machine.  After several vacuum passes, the carpet should only feel damp, not soaking wet.  (From experience, I once wetted down a large area of my sofa before discovering that the suction of the cleaning machine attachment wasn’t working!  I was blessed to have a wet-dry vac available as a backup). 

Unless you have those nifty molded floor mats that capture the dirt and water that you track in, there is going to be dirt and there is going to be mold in the floor of your car.  Mold thrives in dirt and moisture.  Even if the carpet is not stained, it’s a great idea to clean the carpet at least once a year to remove mold and dirt.

Now that you’ve removed the sources of mold in your car, you can add some non-toxic scents back into it.  Here is a video with 6 different ways to make non-toxic car air fresheners using essential oils and different items to hold the scent. (The speaker may be a bit difficult to understand, but the sachets she mentioned are muslin drawstring bags and the last item she sprayed on was wool felt–a very natural, absorbent material).  If you don’t have the time to make your own, just order some vent clips or auto stix from Enviroscents, a company that does not use toxic materials in any of their products.

Ahhh!  It may be a bit of work to achieve, but who doesn’t like the smell of a clean, fresh car?  For as much time as we spend in them, your health is worth the effort!

Face Masks: the air filters we never thought we’d be wearing

Face Masks: the air filters we never thought we’d be wearing

Pre-pandemic, I grudgingly used face masks to protect from dust and allergens, like when mowing the lawn kicked up dust, or sanding wood projects filled the air outside with dust.  I knew when I should have worn one…usually by a raging sinus headache the next morning.  Nowadays, concerns for our own or others’ health mandates wearing masks in public settings for a large portion of the year.  But–what are the risks versus rewards of masks?  What do they really do for us?

The CDC has plenty of guidelines about masks, including that masking is a “critical public health tool for preventing spread of COVID-19”.  Masks are made to contain droplets you breathe, sneeze or cough out, and provide some protection from droplets from others.  Respirators are meant to filter the air you breathe as well as contain your droplets.  It’s not hard to tell which are masks and which are respirators, according to how loosely they fit, and the materials and style in which they are made.  The CDC outlines the four types of masks and respirators: 

  • Cloth: they should fit well, have a nose wire, and you should not be able to see light through the fabric.  Regulations now prohibit any “exhalation valves” that would allow droplets to escape.  Lots of innovators have offered new designs for cloth masks, even ones that filter more N95 respirators.  Most cloth masks are washable, and wearers need to have clean replacements ready if the mask gets wet or dirty.  Wet masks do not filter properly and increase the leaks around the edges of the mask. 

  • Procedure masks, or “medical masks” are typically the light blue variety that are now readily available in most stores.  They are made from “non-woven” material that can be mass-produced and sold inexpensively so that dirty or wet masks can be disposed of and replaced with a clean one.  Make sure to wear them with the blue side out (or if your mask is totally white, with the soft side toward your face) and to pinch the nose wire to fit snugly.  Cloth masks should be disposed of when they are wet or dirty.

  • Respirators include N95 and KN95 masks that have markings (N95, KN95) to identify their authenticity. Respirator masks should also be disposed of when they are wet or dirty, but if they are only gently used, can be reused by letting them dry out (see more at the end of this post).  It’s important to check if the N95 or KN95 mask you are using is authentic, as many fakes are being marketed and sold in the US.  There are no authorized “children’s mask” in the N95 variety; nor do they have earloops.  

One widespread concern about using masks is their propensity to increase our intake of carbon dioxide (CO2) due to retaining exhaled CO2 in the mask.  Most medical experts say that there is no increase in retained CO2 due to masks, including this video of a respiratory therapist wearing one for 6 hours, with her oxygen and CO2 levels monitored.  However, studies such as the following have shown that elevated CO2 levels are present, and even this Mayo Clinic article mentions that CO2 levels do not increase with medical and cloth masks, but does not say the same for KN95 and N95 masks. 

  • This study of 11 individuals at rest shows that the levels of CO2 in their mask are elevated after only 15 minutes. The study evaluated KN95 masks, valved respirator masks, and powered air purifying respirator (PAPR, which assists in breathing by using positive pressure inside the mask).  The measurements taken for KN95 and valved respirator masks after 15 minutes showed CO2 levels above the threshold for short-term limits (TLV-STEL) which are set by the National Institute for Occupational Safety and Health (NIOSH).  They are much higher than the long-term limits (TLV-REL) set for 8 hours of exposure.   However, measurements using the PAPR were only slightly above the TLV-STEL.  The study concluded that hypercapnia was a real possibility for healthcare workers using masks for extended periods, but use of PAPR prevents relative hypercapnia.  

  • This study shows levels of CO2 while volunteers are at rest sitting or standing still with a mask hovers at approximately 500-700 ppm.  While using a mask, the CO2 concentration in the mask elevates on average to 2200 ppm while sitting or standing still, approx. 2500 when walking at a pace of 3km/hr with a mask, and approx. 2900 while walking at a pace of 5km/hr with a mask.  The conclusion cites that “concentrations between 1,000 ppm and 10,000 ppm can cause undesirable symptoms such as fatigue, headache and loss of concentration”, so those who are required to wear masks for long periods like students, bus drivers or cashiers may be affected.

  • Computational fluid dynamics were used in this study to show that due to the tight fit and mask composition in N95 respirator masks, CO2 levels, water vapor, and temperature are all increased inside the mask.  This leads to excessive CO2 inhalation (up to 7 times more per breath) and reduced heat transfer inside the nasal cavity (which causes the wearer to feel that they have not taken a full breath).   The authors suggested that wearers of this type of mask should limit the time the mask is worn. 

The takeaways from these studies show that it’s not advisable to wear respirator masks like the N95 unless you are in close proximity with unknown and known sources of SARS-CoV-2, and then only for shorter periods of time.  Most of us may wear well-fitting and designed cloth and procedure masks, and there are some great options for specific use out there:

  • Since it’s important that masks fit everyone well, Enro has developed their mask in 6 sizes, making it exceptionally wearable, washable and durable, with an anti-microbial coating. 

  • Seri face masks by Serionix are very soft, comfortable masks with refills that come in a choice of MERV 13 or MERV 16 filter material. 

  • Clear masks solve the problem of not being able to see half of our faces and expressions!  ClearMask seems to be the leader for medical and professional use, but many others are offering different designs with comfort and anti-fog characteristics.  MaMo Creations is a favorite among teachers and other communicators. 

  • The Vocaleasemask offers singers and performers acoustic transparency of materials for greater clarity, and a design for full range of face motion and easier breathing.  It achieves particle filtration above level 2 (the higher level) of the ASTM Standard Specification for Barrier Face Coverings (ASTM F3502-21).

  • Sunnie Face Shields are not masks, but they are popular for protection against droplets as mask requirements are relaxed.  They are very light, anti-fogging, scratch-resistant and extremely durable.  

Now, how can I wear the same mask day after day, safely? 

  • Sometimes, due to shortages, healthcare professionals must re-use their masks. Disinfecting N95 and KN95 masks with soap and water, bleach or even alcohol decreases their effectiveness.  The best way to disinfect these type masks is actually just to let them dry for 48-72 hours.  

  • If you don’t get a chance to wash your cloth face mask everyday, we also recommend letting it dry out (don’t store your mask in a plastic bag!); 

  • You can natural sprays to refresh it and remove odors, such as Cavere, which uses 70% ethanol (alcohol derived from corn or soybean), water, glycerin, peppermint oil, echinacea extract, eucalyptus oil, citric acid, and a few other ingredients.   

  • Mask sanitizing sprays such as CovaGuard use Benzalkonium Chloride (BAC), which does kill viruses but have been known to induce asthma in cleaning workers, decreased lung function in farmers, and greater immune reactions and decreased fertility in mice, among other effects.  

Masks are definitely equipment that we hope will be rendered obsolete soon, but in the meantime, we can keep on innovating with them for better comfort and efficacy.

Photo by Yoav Aziz on Unsplash

Air Quality Myths–debunked!

Air Quality Myths–debunked!

Don’t worry, at HypoAir we’re learning everyday too.  Whether the myth comes from the media, or your family, or just what you assume happens, many of the things we believe about air quality–are not true!  Let’s dive in and get to the bottom of these myths…

  • My old, leaky house has better air quality than new tighter ones because it “breathes”.  Well, yes and no!  Ventilation is good, but if it’s allowing polluted or humid air in, that’s not good!  We like to opt for controlled ventilation, when you can open a window on clear days but on polluted or humid days, close it and still get fresh, conditioned air through special intakes to your HVAC.
  • Air conditioners provide fresh air ventilation.  Actually, most air conditioners don’t provide any fresh air!  Standard central and window units are closed systems, which mean they are simply recirculating (and recirculating…) air within your home.  In order to get fresh air, you’ll need to have a special intake installed on your central unit, which may or may not filter and “condition” the air it pulls from outside.  Check out our post on Adding fresh air through the HVAC system for more info.
  • It’s best to clean your AC ducts every 3-5 years.  This is a myth perpetuated by some duct cleaning companies.  Actually, we (and the EPA) don’t recommend duct cleaning unless you have mold in the AC system, have a pest infestation (rodents, bats or birds usually), or excessive amounts of debris.  Normal dust in ducts doesn’t pose a risk to indoor air quality and it’s best left undisturbed, because there are risks that ducts can be punctured or damaged during cleaning, or cleaning chemicals can leave behind VOCs.  For more info, check out our post “Should I clean my HVAC ducts?”
  • My thermostat takes care of the humidity.  Are you sure?  Standard thermostats only regulate temperature, and when the system meets the temperature goal, it shuts off.  It’s best to have a second monitor, like our humidity sensors, to make sure you are meeting your humidity (40-60%) goal as well as temperature. 
  • When it comes to AC units, the bigger the system, the better.  Actually, installing too big of a system (central or window unit) will cause a problem called short-cycling, where the unit turns on, quickly brings the temperature down, but does not have time to reduce the humidity.   This is definitely not good for your home or the machinery, because damp air can cause mold and mechanical issues.  Lesson: the correct size is better!  Contact an HVAC tech to perform a load calculation to size the unit correctly. 
  • It’s normal for the upstairs of the house to be warmer.  Well, to some degree, but it doesn’t have to be a completely different climate than the lower story.  The two areas are called “zones” and even if you only have one AC unit, you can get the system “balanced” so it works less to keep both zones at comfortable temperatures.  Check out our post “Why selecting and sizing your AC system is critical for healthy air”.
  • I don’t always need to use the stovetop ventilation when cooking.  Yes, you do need it a lot more than you thought–roasting meat, baking, and even stovetop cooking that only creates fumes for a few minutes all exude a lot of VOCs and particulates from the pans, oils and food.  Cooking with gas emits much more fine particulates (PM2.5) into the air than electric. 
  • If a cleaning product has a natural smell, it’s not toxic.   Sorry!  This myth is why detergent companies market their products to smell “natural”, but load them with many toxic ingredients.  Also, some of the VOCs found in nature (like limonene, a citrusy smell) can react with other chemicals to form harmful pollutants.  Our recommendation would be to use products like TotalClean, which have no fragrance but do the cleaning job, then use your favorite essential oils to add a safe level of fragrance to your home.  Check out our post “Ewww!  How can I get rid of that smell?”  (hint–TotalClean works great as a deodorizer also!)
  • My personal products have nothing to do with my allergies/sinusitus/congestion.  Actually, they definitely could. Since the chemicals in our shampoos, soaps, lotions and deodorants are among those that form ozone in summer smogs, they can hang around in your house and on your body long after showering (Guardian article), causing respiratory irritation.  Some of the ways that we can reduce their effects on us is rinsing for longer, using  the bathroom vent (ideally continual use for 30 minutes after showering to reduce moisture in the bathroom too) and switching to non-aerosol products. 
  • Bleach is the best way to kill mold. Bleach certainly kills mold, but it also dangerous to your respiratory system and skin, and can react with limonene, a common citrusy-smelling VOC found in other cleaning products, to form secondary organic aerosols (SOAs), which are minute particles that compose smog.  There are a number of less toxic products that can kill mold, such as TotalClean (which contains iodine), hydrogen peroxide, vinegar, baking soda, grapefruit seed extract, etc. (be careful about what you mix together though!)  Check out this article for some natural solutions to clean up mold. 
  • If the EPA allows the sale of a household product, then it’s not toxic.  Unfortunately, the EPA does not know all of the ingredients that household products contain, because they are not required to be disclosed.  Organizations like the Environmental Working Group (EWG) and Women’s Voices for Earth (WVE) have tested many household products to reveal the toxic ingredients they contain.  Check out our post “Reasons not to use your mama’s (or grandma’s) cleaning products”, to be better informed for healthy purchasing!

Do you have an “Air Quality Myth” you would like for us to address?  Let us know!  

Reasons not to use your Mama’s (or Grandma’s) cleaning products

Reasons not to use your Mama’s (or Grandma’s) cleaning products

They say that family traits tend to skip a generation.  In my case, the cleaning habits did skip a generation, because my grandma would rather be outside or repairing a bicycle (her hobby), and I would definitely rather be doing anything outdoors than cleaning inside!  In any case, her old cleaning products like Pine-Sol and Simple Green are still around, but I found out that whenever I do get the urge to clean, I should not be using them.  What triggered my concern?  Several things, first being I knew from previous research that heavily-fragranced products contain a lot of toxic chemicals (see the post on Ewww! how can I get rid of that smell?).  Secondly, a recent study showed that simply mopping a floor with a normal terpene-based cleaner released as many nanoparticles into the air as are on a heavily-trafficked city street (yikes!).  I definitely am glad I do not have to clean as a profession.

Here are some common products (most of them overly-fragranced) that need a makeover.  

Pine-Sol: For some reason (probably because we lived in the woods) my mom favored Pine-Sol for cleaning our linoleum floors and the toilets and cleaning-wise, it seemed to do a decent job.  I even used it to clean my first apartment in the 1990’s.  However, it was recently discovered by Women’s Voices for the Earth (WVE) that many brand-name cleaners have hidden toxic ingredients, because manufacturers are not required by law to disclose all ingredients.  Their study and test-results give the details.  Pine-Sol contains toluene, which can cause pregnancy complications, limonene, which can cause allergies, and carbon tetrachloride, which is at least an irritant and at worst shown to cause kidney and liver damage.  According to the EPA it has already been discontinued from consumer use, but obviously manufacturers who are not required to disclose all ingredients to the consumer are also not purposefully disclosing to the EPA. 

Simple Green: Sounds pretty good, right?  I never like the smell of Simple Green, and maybe now I know why, because it was on the aforementioned study by WVE.  The formulation “Simple Green All-Purpose Cleaner Non-Toxic Biodegradable” contains toluene, and “Simple Green Naturals Multi-Surface Care Lemon Verbena” contains phthalates, which cause hormone disruption and neurodevelopment disruption, and 1,4-dioxane, a cancer-causing ingredient.  The manufacturer was already ordered to pay $4 million in a class action settlement (2021) for making misleading claims about being a “non-toxic” cleaner.

Fabuloso: I was not familiar with Fabuloso until I started visiting family homes of a Latina friend.  It is quite popular in the Latin community, as it was created in Venezuela.  Full-strength Fabuloso, though formulated to emulate botanical fragrances like lavender and “spring in bloom” is very strong on the nose and eyes and every part of your respiratory system.  This smart Latina dug into  disclosed list of ingredients to find it contains Sulfuric Acid, 2 Phenoxyethanol, Sodium Hydroxide, Propylene Glycol Propyl Ether, and Alklbenzenesolfonic Acid, all of which are mild to severe respiratory irritants.  The EWG gives the Fabuloso Lavender Multipurpose Liquid Cleaner, one of the most popular fragrances, an “F” grade for toxicity.  It is certainly not “Fabulous”, and the not-uncommon habit of boiling it on the stove to perpetuate the fragrance can damage lungs and cause asthma in children.   However, it is a brand leader globally and a cultural icon, which means it will probably not die slowly.  

Do you want to be sure that you’re not breathing toxic nanoparticles or chemicals when you clean and afterward?  There are a couple of easy ways to do that.

  • First, you can use natural cleaning products over chemical agents. (20 Ways to Reduce Indoor Air Pollution in Your Home)  There are many DIY cleaner recipes online that use simple ingredients like baking soda, lemon juice and non-toxic soap, that you probably already have in your pantry or cleaning cabinet.
  • Our new product TotalClean is the one to replace floor cleaners, countertop cleaners, toilet cleaners and even spray deodorizers, because it performs well in all of these categories without toxic chemicals or fragrance.  If you want to add in fragrance, try adding a few drops of your favorite essential oils, which can be changed for your mood or the season.  This product has already replaced my Windex and Febreeze (also on the WVE list), and another countertop cleaner.  

With good non-toxic cleaners, maybe cleaning will move up the priority list–you never know!

How does indoor air pressure affect ventilation and air quality?

How does indoor air pressure affect ventilation and air quality?

If you’ve read some of our posts, you’ve probably heard how passionate we are about ventilation for indoor spaces.  Most old and new buildings just do not have sufficient fresh air flowing in, resulting in ill health for the building and its occupants!  This post is about the role indoor air pressure plays in ventilation and air quality. 

The air pressure we’re talking about inside your home is relative, meaning, it is higher or lower relative to the outdoors pressure.  Normal outdoor air pressure at sea level is 101,325 pascals, which is also equal to 14.7 pounds per square inch, or 29.92 inches of mercury, and it can go up or down slightly according to the weather.  Now, if the air inside your home has a pressure lower than the outside, then it would be slightly lower than 101,325 pascals, and the relative pressure would be the difference between the two pressures (like 20 pascals).  

If your home is very tightly sealed, it would be able to maintain a pressure differential like this for some time.  However, this is very rare.  Most homes are not tightly sealed, so air will flow from the area of higher pressure to the the area of lower pressure (in this case, from outside to inside).  Air pressure, like water and other sources of energy, tend to flow from high to low pressure: this is the second law of thermodynamics, which is explained well here

Air pressure differential has been used to control air movement for a long time.  Negative pressure has been a principle in design of multi-family homes and apartment buildings in order to get fresh air to ventilate the building.  In this case, constant negative air pressure inside the building is needed to continually draw fresh air in from the outside through passive vents or windows.  To generate negative air pressure, architects place exhaust vents in strategic places, like bathrooms and kitchens, where it’s desirable to draw out humid, odorous air anyway, and feed them into ventilation shafts.  This part of the design is not the problem, however; the problem is that the apartments or homes are not tightly sealed, so that replacement air (flowing into the negative pressure space) does not always come from dedicated passive vents or open windows.  If it’s too cold or too hot and windows are closed, air may be drawn in from the neighbor’s (smoky) apartment, or through leaks on the side of the building beside a busy street, or through the corridor and door leading from the parking garage.  

The only way to get negative pressure ventilation to work in a controlled way is to (very) tightly seal the home. During a research project for for the Building America program under the National Renewable Energy Laboratory, Steven Winter Associates sealed several apartments manually (using weatherstripping, caulk, etc.–see below “apartment sealed to 0.27 CM50/SF”), and UC Davis sealed several other apartments using an aerosol sealing technology (see below “apartment sealed to 0.08 CM50/SF”).  This is where a fog of sealant is applied while pressurizing the apartment, so that air flowing out of the apartment carries the sealant and “plugs” any leaks along the way.  Of course, this method can only be applied before the apartment is finished, however, the “tightness” of the building envelope achieved by this technology is dramatic, as shown in the graphs of the ventilation tests. 

Photo of aerosol sealing during installation (

It can be inferred from the graphs that getting sufficient fresh air from dedicated vents is only possible when the apartment or home is tightly sealed–otherwise air is just as likely to come from undesirably-located leaks and other apartments.  Sealing a home to 0.1 CM50/SF or less, as in the second graph, is uncommon even in the best “green” buildings.  Therefore, relying solely on negative pressure ventilation is not an effective strategy–especially if you’re interested in good indoor air quality while looking at buying an existing home.  

Let’s switch over to positive pressure ventilation.  This strategy is used in “clean rooms”, CPAP machines (continuous positive airway pressure), and wherever you want to supplement a space with fresh air in a controlled way, not just allowing outside air to flow in by chance.  The air supplied will come from the outside, but in order to make sure it’s clean and at the right temperature and humidity, it will need to be filtered and “conditioned” if necessary, by the HVAC system.  As an example, the AirCycler g1 ( comes with a programmable damper system.  It will open the fresh air intake damper as required and run the air handler fan on a user-specified schedule (typically, for 10 minutes every ½ hour to 1 hour).  This works fine in normal homes, which are leaky enough that the house is not really pressurized to any great extent- air will just flow out of the available cracks and crevices of the home.

Third, with modern technology, we can even get ventilation with no pressure differential, which is called a “balanced” system.  The simplest concept is to utilize a system such as the Aircycler g2 and your bathroom exhaust fan.  The g2 will tell the bathroom exhaust fan to turn on at the same time it opens and turns on the air handler unit, causing your HVAC unit to pull fresh air in through a damper, filter and condition it, distribute it throughout your home, and exhaust stale air through the bathroom exhaust vent.  In this manner, there is no appreciable pressure differential, just 2 fans working to add fresh air and exhaust stale air from your home on a predetermined schedule/volume.

For a practical demonstration of the differences among these 3 systems and how to measure air flow, I suggest this video

The next “upgrade” to the balanced system is using an HRV or ERV (heat recovery ventilator or energy recovery ventilator), which works with your HVAC to reduce energy costs of pulling in that fresh but unconditioned air.  When there is a large temperature or humidity differential between the outdoors and indoors, simply dumping outside air into your HVAC inlet causes it to use a lot of energy to bring that air up or down in temperature and humidity.  A heat recovery ventilator will use the temperature of the exhaust air to close the gap in temperature, and an energy recovery ventilator will use the temperature and humidity of the exhaust air to close the gap in temperature and humidity.  UltimateAir, AprilAire, Panasonic, Broan, Honeywell and FanTech are some of the manufacturers of whole-house ERV’s, which have a larger up-front cost than negative, positive, or balanced systems alone, but have payback periods of 3 years or less when you factor in the energy cost savings.  

There is one more consideration when deciding on what type of ventilation to pursue: condensation.  Both negative and positive air pressure will cause condensation in undesirable places if there is an extreme difference in air temperature between inside and outside.  This is most notable in the following situations: 

  • With negatively-pressured rooms in the summer, unintended leaks can draw in humid air and cause condensation and mold problems.  This happened on Texas A&M campus in several buildings due to poor design or building change orders during construction (study)
  • With positively-pressured homes in the winter, at some point in the air passageway to the outside, the warm moist air from inside encounters a cold surface and condensation and mold can form (

Here are some pros and cons to these different systems:

Type of System

What it is



Negative Pressure

Uses bathroom or kitchen exhaust fan to create negative pressure inside house and pull fresh air in through passive vents or leaks

  • Least expensive
  • Can be controlled via timer
  • In normal homes leaks cause “fresh” air to come through random and undesirable places
  • Fresh Air flow is not evenly distributed in home
  • Can cause condensation and mold deep in structure when temperature and humidity differentials occur (usually in the summer)

Positive Pressure

Uses a damper to pass fresh air into the HVAC intake for distribution in the house

  • Keeps humid air out of the house in humid climates
  • Uses a large fan (air handler) to move and condition a small amount of air, when the system is not actively heating or cooling
  • Loss of heated or cool air when venting
  • Can cause condensation and mold deep in structure when extreme temp differentials occur (usually in the winter)



Combination of intake damper and bathroom exhaust fan

  • Utilizes systems that are already present in home, with addition of damper and scheduling electronics
  • Evenly distributes fresh air in home
  • Uses a large fan (air handler) to move and condition a small amount of air, when the system is not actively heating or cooling
  • Loss of heated or cool air when venting

Balanced ventilation with HRV or ERV

Two fans (one for intake and one for exhaust) combined with a heat exchanger to recover energy from vented air

  • Value of vented, conditioned air is not wasted because some energy is recovered
  • Does not actively pull in air through leaks
  • Evenly distributes fresh air in home
  • Most costly upfront but realizes energy savings for a 1-3 year payback


There you have it–the 3-½ ways of ventilating your home!  If you want to measure the pressure in your home or a home you are thinking of purchasing, manometers are used to measure air pressure and other gas pressures.  It’s possible to make a simple manometer with some plastic tubing, colored water and a few other supplies, but if you want to measure the pressure of a room, you’ll probably want to use a digital manometer.  This is because very slight air pressure differentials are generated for ventilation purposes within homes, and it would be hard to distinguish them with the homemade manometer.  For example, only 20 Paschals of negative pressure, or 0.08 inches of water, should cause the required 7.5 CFM of air to flow through a trickle vent for dilution ventilation, but this would be difficult to measure on a homemade manometer.  Digital manometers are best suited for this purpose, and ventilation supply companies sell them, or you can rent them in select states from some companies (such as JMTest).

In order to measure the pressure of a room (for example, a negative pressure room like a bathroom) with reference to another room (the hallway outside) with a digital manometer, you will need to: 

  • Turn on the manometer and make sure it reads zero differential pressure.  If not, use the owner’s manual to “zero” the instrument.
  • Prepare the manometer tubing–make sure it has no kinks in it.  Connect the tubing to the negative port. 
  • Turn off the exhaust fan of the bathroom.
  • Close all the doors and windows to the room you are measuring.  You will be standing outside in the hallway, which is the “with reference to” room. 
  • The positive port will remain open/unconnected to any tubing.
  • Place the other end of the tubing under the door of the bathroom and allow pressure to stabilize, then record reading.  There should be very little to zero pressure differential. 
  • Open the door and turn on the exhaust fan, then close the door again (remain outside).
  • After a few minutes of running the exhaust fan, take a reading and record it.  This should be a reading similar to ‘0.2” w.c.’ which is a slight pressure differential in inches of water column, a standard unit of measurement for ventilation pressures in the US.
For more details and helpful hints on using a manometer, check out this article on  Soon to come, we will have a guide on how to check ventilation and air quality in your home or any home you may potentially purchase.  It’s a new mindset, but we want you to change from location, location, location to ventilation, ventilation, ventilation! 

Photo by Mufid Majnun on Unsplash

Do Trickle Vents Really Work?

Do Trickle Vents Really Work?

In our post “How does indoor air pressure affect Ventilation and Air Quality?” we discussed the pros and cons of negative, positive, balanced and balanced with HRV/ERV ventilation. We really do think that balanced ventilation is the way to go, but not everyone is convinced.  In the UK and Europe, negative pressure ventilation is common through the combined use of trickle vents and kitchen and bath exhaust fans.  Trickle vents are offered on new window frames and there are options for retrofitting them into existing frames.  

It may sound like a drippy register, but “trickle vents” are designed to provide “background ventilation” and remove condensation from a house. They supposedly have several advantages:

  • You can ventilate your home during most types of weather, no matter if it’s rainy or not.  The design of most trickle vents does not allow water to be forced in even during windy rainstorms.

  • You can ventilate your home more safely than opening the window.  Homes and apartments with first-floor access have considerably more risk of break-ins than higher stories, so opening windows, even with nightlatches, is often a safety risk.  Trickle vents allow safe ventilation, whether you’re at home or away.

  • You can control the ventilation with adjustable trickle vents.  Too much draft on a cold day is not nice, so you can open the vent partially or close it altogether on some windows.

  • Trickle vents supposedly provide minimal ventilation where homes are built tightly and windows are rarely opened.  This allows toxic chemicals that build up from off-gassing and normal daily activities like cooking and cleaning, to be diluted and vented.

  • Trickle vent options include ones that automatically open at preset humidity or temperature levels.

Of course, there are cons to trickle vents.  Complaints most often center on noise and wind.  If the home is located on a busy street which has a lot of car and truck traffic, or is in a windy area, trickle vents break the insulative qualities of the window to let in traffic and wind noise.  Some designs are better than others at attenuating noise, so design of the vent is important to consider when installing new windows. 

Now, do they work?  Since they were mandated in the UK for some time (2006-2021 from what I’ve read), it seems to me that they were proven to do the job, but in reality, they probably were not.  According to a research project funded by the National Renewable Energy Laboratory as part of the Building America program (here is a summary by one of the authors), fresh-air ventilation like trickle vents usually does not work the way it is intended.  In order for it to do so, the home must be sealed very tightly except for the vent, and rooms must be in constant negative pressure.  In most cases (which are normal or poorly sealed homes) cracks around the main entrance door overwhelmed the amount of ventilation coming through dedicated vents like trickle vents.  Ventilation in multi-family homes in particular is unpredictable, because pressure in the corridors and apartments fluctuate depending on weather, wind, and occupation of the buildings.  The end result is that the theory of exhaust-only ventilation was not working in real life.  According to the theory, “consistent negative pressures of up to 20 Pa are needed to draw air from the vents at the rates desired”.  No wonder there are so many moisture, mold and air quality problems in modern homes!  The air exchange is not working as exhaust-only ventilation plans have been designed.

In the end, the author of the aforementioned research project still advocated for tighter buildings and controlled ventilation via balanced ventilation and energy recovery units and whole-home dehumidifiers (if necessary).  These do have higher up-front costs, but they deliver consistently healthier air, and the paybacks are short (under 5 years).  

Obviously, if I lived in the UK and was required to have trickle vents in windows, I might not be inclined to “do the research” because they seem to be a reasonable source of ventilation.  Living in 2022, even better ways of getting fresh-air ventilation are constantly being designed and with many sources of information at our fingertips, we can choose more wisely.

Photo by JamesKingdom on Wikimedia