All Posts by Jennifer Faul

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Enduring the Rainy Season

Enduring the Rainy Season

Many kinds of climates may exist in your state, from hot and dry to cool and humid, depending on your elevation, weather patterns, proximity to water, etc.  Although mold can grow anywhere (even in the desert!), more water definitely means more mold.   Your “rainy season” can come in January or July…but it matters most that you are ready for it and know what to expect!

Taken from somewhere that REALLY gets their share of rain, in the Philippines it is common for people to get sick during the rainy season and even while transitioning from one season to the next.  The following advice from the Philippines could go a long way in the US, as well!

  1. Pack your rain gear.  An umbrella is a must on days that it might rain, which includes some that start out sunny!  We’re not saying that getting wet automatically makes you sick, but here’s the connection: wet clothing can lower your body temperature.  Lowered body temperature causes the blood vessels in the nose to constrict, which in turn limits the number of white blood cells that can come to your mucous membrane to fight off infections.  This is the type of lowered immune response that leaves you susceptible to viruses and microbes!
  2. Warm up quickly after you get wet by taking a warm shower, or at least changing into warm dry clothing.  Making a habit of washing your hands after traveling also helps!
  3. Drink lots of clean water!  This is another part of keeping your body’s immune system healthy.
  4. Use mosquito repellant: It seems like new mosquito-borne diseases are discovered every year, so if you’re going to be outside, make sure they don’t target you by applying a non-toxic repellent like Wondercide Insect Repellents
  5. Make sure that mold is not creeping into your home with water intrusions.  More water outside running over your home can lead to small or major leaks, which can go undetected if you aren’t vigilant!  Keep bedroom doors open for ventilation and check unused rooms at least weekly for any signs of leaks.  You may want to also leave ceiling fans running to increase air circulation, which has a drying effect.  Mold spore counts will increase outdoors during the rainy season, but you can keep them down indoors by:
    1. Using a HEPA air cleaner:  Medify has a great selection of air purifiers that are simple to use and a good value for the size of room purified. 
    2. If you believe that mold spores are increasing in your home’s air, there are several ways to deactivate them. Plugging in a Germ Defender, Upgraded Air Angel Mobile or installing a Whole Home Polar Ionizer, all of which use bipolar technology, kills mold in the air and on surfaces. Alternatively, Air Purification Candles actually lower the spore count.  They don’t have fragrance so you don’t have to worry about nasal irritation.  You can check out our article on them here!
    3. Keep a close eye on humidity levels in your home with these inexpensive humidity sensors–place them in several rooms so you don’t have to look too long to know what’s going on with the humidity!  If you see it creeping up, it may be time to research dehumidifying settings on your HVAC system or add a dehumidifier.

Your environment may make you feel like you’re living underwater, but do your best not to let it affect your health or the health of your home.  Where there’s moisture, there’s life–just make sure it’s the beneficial, beautiful kind by preventing mold  and microbe growth.

It’s a dehumidifier that doesn’t use electricity AND has no moving parts!

It’s a dehumidifier that doesn’t use electricity AND has no moving parts!

Our clients know that here at HypoAir, we’re all about managing humidity for a healthier home.  If your house is above 60% humidity, you can start to have mold problems (the higher the humidity, the more quickly mold can grow).  We’ve written on dehumidifiers of all sizes for any room in your home, but none of them tops what this invention does.  It’s a passive dehumidifier that “sucks” the moisture out of air and evaporates it outside with help from the sun, even when the outside humidity was higher than inside!

Some of the best inventions have been developed by observing nature, called biomimicry.  In this case, researchers observed how trees “transpire” moisture, which includes lifting water from the roots to the leaves, where it evaporates through the pores, or stomata, of the leaves.  Thus, there are two parts of the tree that function in transpiration: the trunk of the tree contains xylem, which are very small capillaries or “straws”, and the pores in the leaves.  The sun’s energy starts the evaporation process and actually creates a negative pressure in the xylem, essentially sucking water up from the ground to the leaves.  (How do large trees, such as redwoods, get water from their roots to the leaves?)  

Researchers searched for similar behavior when they developed materials to mimic this water movement.  Two different materials were needed: one to absorb the water from the air (super-hygroscopic) and one to readily enable it to evaporate using the sun’s heat.  Metal-organic frameworks (MOFs) have been the subject of enormous research in the last decade.  They are like activated charcoal on steroids; because of their structured pores, internal surface area is huge.  When comparing the surface area per unit weight, the activated carbons are 400–2000 m2/g, zeolites up to 1500 m2/g, and MOFs are in the 1500–7000 m2/g range. MOFs are the porous materials with the highest surface area, with an ultra-high porosity of up to 90% of free volume.  (MOFs vs. other porous materials for carbon capture)  On top of this, MOFs can be custom-built to “adsorb” many different gasses or liquids, such as water, VOCs, metals, etc.  Thus, it made sense to make a very thirsty (hygroscopic) MOF to suck up water vapor, also known as a desiccant.  The researchers decided to try impregnating Lithium Chloride (LiCl, a salt) into an MOF. MOFs are typically granular, like sand, but the researchers wanted this component to be self-supporting, so they decided to nanospin the MOFs into a nanofibrous membrane (NFM) using polyacrylonitrile (PAN), a synthetic polymer resin.  The NFM would also enable the component to have a fast moisture absorption–desorption rate.  Thus, the “straw” component of the dehumidifier is abbreviated (PAN/MIL@LiCl) NFM, with MIL describing the “multilayer”. 

Passing the water vapor through to the outside of the space, the other component had to allow heat from the sun to evaporate this water, creating the “wicking” action.  This is the photothermal component.  Carbon black is a fine black powder produced by partial burning and pyrolysis of oil residues or natural gas at high temperatures.  (Carbon Black 101)  The black color works well to absorb solar heat, and adding it to a PAN NFM (PAN/CB) allows for great surface area, and thus evaporation rates.  The two layers put together are abbreviated PAN/MIL@LiCl-PAN/CB or for short, PML-PC NFM.

How did this layered dehumidifier configuration work out?  Impressively!  Being semi-flexible, it could be laid flat as a dehumidifier “panel” in a roof, or deformed to allow for water harvesting from the air (see diagram below). The scaled-down model of a house was constructed with dimensions of 40 cm × 50 cm × 40 cm, and a window with an area of 6 cm × 6 cm was designed for bilayer membrane installation. When light from the solar simulator illuminated the surface of the bilayer PML-PC NFM, the moisture in the indoor air was pumped by bilayer PML-PC NFM and simultaneously transported outdoors in the form of water vapor. The moisture actively moved from a high-humidity to a medium-humidity environment and also from a high-humidity to an ultra-high humidity environment through bilayer PML-PC NFM under sunlight irradiation. This is a unique advantage in terms of the dehumidification ability of the novel NFM-based moisture pump compared with traditional desiccants.  When the device was placed in an environment with an ambient humidity of 46%, the indoor RH was reduced from 70 to 48.9% within 2 h using bilayer PML-PC NFM.  When the device was placed in an environment with an ambient humidity of 80%. The indoor RH in the house model steadily decreased from 70 to 58.3% within 2 h using bilayer PML-PC NFM.  These are lower humidity ending points than that of the NFM without a photothermal layer. (Super hygroscopic nanofibrous membrane-based moisture pump for solar-driven indoor dehumidification)

Source: (Super hygroscopic nanofibrous membrane-based moisture pump for solar-driven indoor dehumidification

Now, what if night falls or clouds obscure the sun?  Since the experiment used a solar simulator of 1 kw/M2, which is the maximum amount of sunlight that can be had at the equator on a cloudless day, that would be a pretty intense artificial light needed to keep dehumidifying through the night or clouds.  For these reasons, this material would work best in an area with a high percentage of sunlight year-round, and lots of need for dehumidification (like the tropics).  Is it affordable?  Although the information in this paper is now 3 years old and other water-harvesting MOFs have been created, we don’t see any commercial applications yet, sadly.  Making such a technology affordable will do a lot to improve air quality in homes where energy (and dehumidifiers) are relatively expensive, since it doesn’t require electricity to condense humidity or regenerate the desiccant.  It could also allow many people to have access to clean drinking water by “pulling it out of thin air”.  We think it’s just too cool of an idea to keep to ourselves!

As for “natural” dehumidifiers, there are many materials that are hygroscopic: rock salt, calcium chloride (DampRid), baking soda, even sugar and honey.  The most efficient material we’ve seen is rock salt, most of all because it can be recycled: simply retain the liquid, let it evaporate in a pan outside in the sun, and break up the chunks to reuse it again (be sure to protect animals and children from drinking it by placing a screen over it!).  The downside to a rock salt dehumidifier is that it will only draw humidity down to 75%, which is the humidity that causes the salt to dissolve.  Also, using it in basements or porous/non-sealed areas is quite a lot of work for the results, as moisture is constantly being replenished from the ground through the concrete.  Finally, if you don’t recycle it, the liquid is quite toxic to vegetation, animals and can damage some surfaces.  

Some plants also act as natural dehumidifiers.  Check out the videos of the desert plant T. aphylla, native to the Middle East, which moves salts from the local soil to its branches and uses them to harvest water from the air!  The salt crystals on its branches change from a crystal structure during the day (low humidity) to drops of liquid at night, which it can absorb through its foliage.  If you have a normal “green thumb”, check out this article for a list of indoor plants that dehumidify.  Of course, we are all for natural, non-toxic and low-energy ways to improve the air in our homes!

Photo by Vivint Solar on Unsplash

10 Ways to Improve Air Quality in Your Home for $50 or less!

10 Ways to Improve Air Quality in Your Home for $50 or less!

We all like easy, cheap tasks that bring a lot of satisfaction when they’re done.  Why not focus on your air quality the next time you’re in the mood to DIY?  Here’s a list of things that only take a little preparation and a little time, but can make a big impact in the air in your home.  

  1. Are you on an HVAC filter change schedule?  If not, it’s time to change that!  Dirty HVAC filters have a number of negative consequences–from increasing the dust and mold in the evaporator/air handler, to possibly even causing damage to your expensive system.  If you don’t have any filters, just click here and order some from us, and we’ll have them at your door shortly!  If you’re not sure which “MERV” to order, read through the information on the page, and/or contact us to find out.  (Per filter cost is much less than $50).  Then, set a reminder on your calendar to change them regularly.

  2. Clean and adjust your fans for better air circulation: Fans make a BIG difference in quality of air because airflow is critical in this process to 1) get air moving, which reduces pockets of stale air or humidity, and 2) introduce fresh air, which dilutes contaminants and refreshes us!  (for more info check our article here)  Here’s a short list of fans that will need attention: 

    1. Ceiling fans need periodic cleaning and seasonal direction adjustment.  Get yourself an extendable duster that can be used wet or dry (we recommend dry first, then spritz with some TotalClean to get it cleaner).  The fan should also rotate in the correct direction: clockwise in the winter and counterclockwise in the summer (there should be a switch on the remote OR on the fan motor to control rotation direction).  

    2. Portable fans are important for spot cooling and can get pretty dusty!  Some are easy to remove the grill cover, the fan blades and dump them in a sink with soapy water.  For others, use a brush attachment on your HEPA vacuum to clean all accessible surfaces.  

    3. As long as you have your HEPA vacuum with brush attachment out, just scoot on over to the refrigerator and use it on the front grille at the bottom (and/or the back of the fridge–some models have a grille there also).

    4. Bathroom vent fans can also get pretty dusty.  Turn off the power at the wall and if you can, get on a ladder to remove the grille and dust out the inside of the unit, wash the grille and replace it.

    5. Kitchen exhaust fans probably top the list in the grime category!  We have a short article on how to clean them, and even use activated carbon media to make the kitchen smell better!

  3. Fall is the perfect time to get more fresh air into your home, but sometimes more filtration is needed.  Our Nanofiber PureAir Window Screens catch more fine particles than regular insect screens, so you can have fresh air without the dust and pollutants that normally come with it.   If you have window screens in your home, replacing them with this material is very easy, even for beginners, and we recommend several methods to do it on the product page. 

  4. You know that accomplished feeling when you’ve just cleaned the inside of your car?  Well, here’s a shortcut…order and replace your car’s Cabin Air Filter with a new one that has activated carbon in it.  True, the coffee cup behind your seat won’t disappear, but your car will smell much better, and it will filter out more pollution from other vehicles on the road. (and it might even inspire you to clean the whole inside of your car!)

  5. It may sound like a paradox, but cleaning the dishwasher every few months is really necessary!  As you can see in this video on how to easily remove and clean the filter, the hidden parts can get nasty and slimy!  If you don’t have time to properly take apart and clean your dishwasher, you can try using a highly-rated but non-toxic dishwasher cleaner, which uses citric acid as its active ingredient.  You can use TotalClean or a DIY cleaner to wipe down the door seals and any other parts that can’t be removed.

  6. Set yourself up for cleaning success!  Chances are, if you don’t have the right tools in the right place(s), cleaning will not spontaneously happen!  Case in point: I used to keep 1 spray bottle of TotalClean under the kitchen sink, and paper towels on my kitchen counter.  After researching and writing about the “toilet plume”, however, I knew I had to increase frequency of cleaning the toilet and other surfaces to at least every other day.  Here’s what to do:

    1. Keep a non-toxic spray cleaner and disposable wipes (like paper towels) in the bathroom so that you can easily clean surfaces every few days.

    2. Keep a stash of hand towels and bath towels in a closed bathroom cabinet to change them out several times a week.

    3. If you use a floor cleaning machine like my highly-rated CrossWave, make up a non-toxic cleaning solution and place it in a labeled jar so that you can break out your machine and get going at any time!  Here’s the recipe I like to use. 

    4. Keep a cleaner where you charge your phone.  (Yes, we’re not supposed to, but many of us keep our phones beside our bed at night.)  In that case, dampen a few paper towels with TotalClean and place in an airtight container so that you can sanitize your phone easily and quickly.  

  7. If you or any of your family are susceptible to toenail fungus or athlete’s foot, here is an uncomfortable fact:  fungus can live in your shoes for up to 20 months, and it can even persist in socks for several washings.  To get rid of fungus from washable shoes and socks, (and towels and sweaty clothing in separate loads), add 2 oz of EC3 Laundry Additive to the rinse cycle reservoir of your washing machine.  Not only will it eliminate mold spores from your shoes and clothing, it will also help to clean the washing machine, which can also harbor mold.  (Mold is a type of fungus).

  8. I cannot overstate the positive effects of adding mattress and pillow encasements, and ripping out old carpet in my bedroom.   My breathing and sleep quality have improved drastically by eliminating these materials where dust mites live and multiply.  Here’s what to do; it even works on old mattresses!

    1. Order a real mattress encasement and pillow covers for the bed(s) you want to protect.  Mattress encasements like these by Hospitology have tight-weave microfiber (which do tend to make you sleep warmer til you get used to it) and zipper ends that have velcro coverings so that no dust mites can get in or out!  This is death to dust mites; check out more encasement recommendations here

    2. When you decide to install your encasements, wash all your sheets and and blankets in hot water and your detergent of choice, so that any dust mites will die in the washer.

    3. Install your encasements (it may take another person because it fully encloses the mattress like an envelope that’s only zippered on one side), making sure that all toppers and thick mattress covers go inside the encasement.  You don’t want to leave anything that cannot be easily washed outside.  Now, any bugs living in your mattress and pillows will starve and be contained within the encasement (kind of gross but wayyy cheaper than buying new mattress and pillows). 

    4. Make your bed with fresh clean sheets and blankets and have a great night’s rest!

  9. The second part of the last recommendation is getting rid of old carpet in your bedroom (or any room you spend a lot of time in!).  Dust mites can also live in the carpet around your bed, especially if pets are allowed in your bedroom.  So, even if you don’t have an alternative flooring plan or budget at the moment, removing the carpet and fixing up the subfloor can still be a big improvement.   Warning: once you rip carpet out in one room, you’ll want to do it in other rooms, too!   Here’s what to do:

    1. Read our article on how to safely remove old carpet, and gather your materials/tools.  Make sure to find out how your local garbage or waste company requires you to dispose of it (bagged vs. unbagged, where and when).  Then, budget at least a few hours to get ‘er done!

    2. Fixing up the subfloor can be as simple as checking for splinters and sharp nails or screws, to sealing it with a non-toxic paint or sealer.  Check out a really helpful article here and a few companies that specialize in these types of paints:

      1. Ecos Interior Floor Paint

      2. AFM Safecoat Concrete Floor Paint

  10. Sealing Air Channels in your attic:  You’ll want to wait until cooler weather for this chore, but the idea is to tighten up your “building envelope” so that your expensive “conditioned air” (hot or cold) is not leaking out or unconditioned air leaking in!  All it really takes is some spray foam in cans, maybe some scrap wood or styrofoam sheet (to block off bigger gaps), the right personal protective gear, and time!  This is really worthwhile to do if you plan on adding insulation (must be done before adding insulation, check with your insulation company to see if they will do it).  

Okay, the last two projects take more time and effort than changing an air filter, but they do make a difference in your air quality.  In the case of #10, it should also reduce your home heating and cooling bill and stop pests and insects too.   In these cases, showing your home a bit of love will return the favor!

Photo by Heather Ford on Unsplash

Air Filter Thickness–is thicker better?

Air Filter Thickness–is thicker better?

All of the homes I’ve lived in (and there have been many) used 1” thick furnace filters.  Far and away, this is the most popular size.  I hadn’t even realized that there is a significant selection of  4-5” thick filters, until I recently went to a big-box home improvement store and looked at the actual size of some of the filters offered in the air filter aisle.  It was eye-opening.  Who uses these giant filters?  Mega-Mansions?

It turns out, even a modest-size home can use a thick filter.  The thickness of the filter:

  • Determines the frequency of filter changes.  With a 4” filter, you can go longer (3-6 months) between filter changes, vs. 1 month for a 1” filter, making life easier on the one changing the filter.   
  • Usually equates to more surface area (you’ll have to check the packages of 1” vs. thicker filters to verify).  Surface area is the square inches of filter material you are getting in the filter.  With thicker filters, they generally do give more surface area, because the pleats are deeper and more tightly spaced.  More surface area means that the pressure drop across the filter is generally lower (which is better for your system).  
  • DOES NOT refer to capacity to filter smaller particles. (Look at the next point: MERV.)  

I took a look at a popular filter site, filterbuy.com.  Here’s the comparison:

20x24x1”: (6) MERV-11 filters for $9.98 each (up to 1 month change) = $9.98 per month

20x24x4”: (6) MERV-11 filters for $19.38 each (up to 3 month change) = $6.46 per month

So, if you actually change on schedule, it seems the thicker filters can also be more economical. 

Filtering capacity: As I mentioned above, filter thickness does not affect the particle sizes that are filtered.  It is the MERV rating that does this. (Check out this post for an explanation on MERV ratings).   I selected MERV 11 for the above comparison, but MERV 13 is the optimal rating for home systems, because it filters out many of the finer particulates (from cooking, burning wood and outdoor air pollution) that can damage our lungs and bodies.  For the same size filter, a higher MERV will increase pressure drop across the filter, so make sure that your furnace/air handler will work with the MERV you select. 

I never thought of this before, but I’m sure it’s been tried because a filter manufacturer posted the answer: No, it’s not good to stack (2) 1” filters in a 2” space.  (colorfil.com)  The reason is that two 1” filters create much more pressure drop than one 2” filter, and the extra pressure drop is not good for your air handler.  Another expert (homeinspectorsecrets.com) likened this to stacking 4-5 coffee filters in your coffeemaker, adding coffee, and then turning on the machine.  It’s not going to turn out well!

Here is a summary of filter thickness:

If you want to increase time between filter changes, you can look into increasing the filter thickness.  For example, for the same cross-sectional filter area (20x24), a 4” filter can give you 3 months between changes, vs. one month for a 1” filter.  This can be good for those who are maintenance challenged (for example, an elderly person who can’t easily access the filter), or for rentals or seasonal properties where someone is paid to do maintenance.  Increasing the filter thickness may involve hiring an HVAC tech to install a deeper filter box.  Here are some points about changing to a deeper filter box:

  • If your filter is currently located at the return air grille (where the air from your house is sucked into the system for conditioning), then you’ll want to change the location of the new filter to be right next to the air handler.  This is because if you install a thick filter at the return grille, it can cause a pressure drop in the duct, which can cause air leaks from the attic, crawlspace or any other unconditioned space to come into your air duct leading to the furnace. You definitely don’t want dusty, hot attic air coming into your AC system, so it’ s better to locate this filter either underneath the furnace or alongside it (homeinspectorsecrets.com). 
  • If you are considering building a deeper filter box, also consider upgrading in MERV rating, up to MERV 13 (see next point).  The way to get a low pressure drop across such a filter is to make sure the filter box is big enough.  A simple rule of thumb for this is to allow 2.0 square feet of filter area (not counting pleats) for every 400 cfm (cubic feet per minute) of airflow.  For example, 600 cfm will require 3.0 square feet of filter (600*2/400), which can be achieved with an 18x24” filter (3.0 square feet) or a 20x24” filter (3.33 square feet).  According to Allison Bailes of EnergyVanguard.com, using this rule of thumb will avoid problems with pressure drop in your system, even with using thicker (4-6") MERV 13 filters.
  • If you are looking to increase filtration, meaning filter smaller particles from the air, you will need to increase the MERV rating on your filters.  Typically MERV 13 is the optimal residential filter, and it’s especially good for those with pets and/or allergies. 

We hope this article has cleared up some questions about these thicker filters, and maybe even induced you to switch over to them.  In this case, thicker is better!

Photo by Brett Jordan on Unsplash

Do Air Purifiers in Classrooms Reduce Illness?

Do Air Purifiers in Classrooms Reduce Illness?

Ahh, this is certainly one time when I’m glad to be working remotely!  As my co-workers send their children back to school, the illnesses (from the common cold to COVID-19) ramp up again in their families as germs get passed back and forth in classrooms.

In 2021, there was a lot of discussion about how to keep students and teachers safe from COVID-19.  Many school districts rushed out to purchase and install air purifiers, with ensuing debate on which purifiers were effective, or in fact, which were dangerous.  It can be a bit confusing, so I headed online to find studies on what works.  I found that across a wide spectrum of experts, the following three solutions to reducing illness and increasing classroom performance are, in order, 

  1. Fresh air ventilation

  2. HVAC system filter maintenance

  3. Air purifiers

This list really is in order of importance.  First of all, air purification technology is great, but we at HypoAir are always in favor of the most natural option first, one that replicates the outdoors, and that will be fresh air VENTILATION.  That’s right, you can put an air purifier in a classroom, but without a continual supply of fresh air to increase oxygen and dilute rising CO2 and virus and bacteria levels, the air purifier can only do so much.  Fresh air can be supplied through an open window if the weather or outdoor air quality is nice, but there should be fresh air ventilation built into every HVAC system so that air quality outside doesn’t limit the quality of air indoors.  Many buildings in the U.S., especially schools, do not meet recommended ventilation rates. The quantity of ventilation depends on how many people are in the room; it should be 15 cubic feet per minute per person. In one study coauthored by Rengie Chan, a research scientist at Lawrence Berkeley National Labs, 85 percent of the California classrooms included failed to meet the minimum standard of 15 CFM per person. Other studies show many American classrooms have an average ventilation rate of only 6 to 11 cfm per person.(wired.com). 

The problem with estimating actual fresh-air ventilation to a room by HVAC is that unless there is an intake from the outside in the system, air blown into the classroom is just being recirculated through the ducts and maybe only filtered once, not adding any fresh air at all.  This type of estimation requires a person knowledgeable about the building’s HVAC system.  If fresh air intake is included, then one expert (Joseph Allen, a professor at Harvard’s School of Public Health) estimates that for reducing Covid-19 risk, the air in the room should be completely replaced at least five times an hour. In a Boston school, the sensor registered about 400 cfm of fresh air coming in through the unit ventilator in one classroom. The room measured 1,010 square feet and had 9.5 foot ceilings: It had 9,595 cubic feet of air. Multiply 400 cubic feet per minute by 60 minutes, divide it by the volume, and you find that the air only gets turned over 2.5 times an hour, which was not sufficient. (wired.com)  However, when conducting another experiment in the same school, they found they could boost air changes to 17 to 20 air changes per hour by opening windows and doors.

An easier way to determine if ventilation is sufficient is by monitoring the CO2 level.  To demonstrate the effect of reducing CO2 levels on disease transmission,  researchers in Taiwan reported on the effect of ventilation on a tuberculosis outbreak at Taipei University. Many of the rooms in the school were underventilated and had CO2 levels above 3,000 ppm. When engineers improved air circulation and got CO2 levels under 600 ppm, the outbreak completely stopped. According to the research, the increase in ventilation was responsible for 97% of the decrease in transmission.(theconversation.com)

Since the coronavirus is spread through the air, higher CO2 levels in a room likely mean there is a higher chance of transmission if an infected person is inside. Based on the study above, experts recommend trying to keep the CO2 levels below 600 ppm. You can buy good CO2 meters for less than $100 online (check out our post including them); just make sure that they are accurate to within 50 ppm. (theconversation.com) What can it hurt to donate (or get together with other parents to donate) several CO2 sensors with remote readings, in order to check the levels of CO2 in your childrens’ classrooms?  

After fresh-air ventilation has been established, let’s look at air cleaning.  In any HVAC system, there should be at least filters in the air returns and they should be changed regularly.  By increasing the MERV rating on these filters to MERV 13, smaller particles like viruses can be filtered out to reduce illness transmission rates.  Changing the rating of the filters should be done in cooperation with the facilities manager in order not to overload the HVAC system, but it is quite possible even if filter box sizes need to be enlarged (see our post on Air Filter Thickness for how to increase MERV rating without increasing pressure drop). 

Third, air purifiers can be considered.  If the school has done what they can to provide adequate ventilation and HVAC filter maintenance, then air purifiers can add another layer of protection by filtering or killing the germs that get by these first two conditions.  In order to be effective, an air purifier must either:

  • pull all of the air in the room through a filter unit several times an hour, OR

  • Send out a non-toxic disinfectant that disperses to all areas of the room.

The first of these can be accomplished with units that include high-powered fans, but these can be noisy.  Noise in a classroom, just like in your home, can be distracting and debilitating for the teacher and students!  For this reason, air purifiers that depend upon air throughput for efficacy need to be evaluated for noise when running at the optimum fan speed for the size of classroom considered.  Also, replacement parts such as filters need to be considered in the total cost.  The cost of a HEPA filter (and possibly UV lamp) for every purifier, for example, can quickly add up to thousands of dollars a year when changes are needed in a school with dozens of classrooms.  Maintenance of these units will fall on the school’s facilities staff, who are likely already over-burdened with an increased cleaning schedule.  

The second option is one that HypoAir promotes because it really is akin to what goes on naturally outdoors.  Ions are one of nature’s cleaning devices, because positive and negative ions are continually floating through the air and reacting with allergens, viruses and bacteria, deactivating them.  These ions are naturally produced by natural phenomena in the air such as sunshine, lightning, crashing water like at the seashore or a waterfall, and plants.  Indoors, we produce them by passing a small electrical charge through stainless steel “needles” to produce positive and negative ions, which get distributed through the air to every part of the room (like adding drops of dye to clean water, soon every part of the water is changed!).  This is done nearly silently, because powerful fans are not required for distribution (any fans already in use in the room will boost circulation of the unit’s small fan).  In addition, maintenance on HypoAir ionizers is virtually nil, because no filters are required and there are no replacement parts.  The cost of running our ionizers is very small, as they use minimal electricity. 

So what about real world testing of these methods?  The CDC released a study on 123 elementary schools in Georgia in 2021.  The schools included did one of three things:

  1. Nothing

  2. Increased ventilation by opening doors, windows or using fans 

  3. Added HEPA filters to classrooms.

In schools that improved ventilation through dilution methods alone, COVID-19 incidence was 35% lower than the schools that did nothing, whereas in schools that combined dilution methods with filtration, incidence was 48% lower than the schools that did nothing.  The takeaway here is that ventilation and HEPA filtration work, even with some added cost for ventilation modification or filter replacements!  Doing nothing, on the other hand, increases the cost of lost school days, makeup time and medical costs for students and teachers substantially.   

It’s a new world with viruses and allergens challenging young and old alike everywhere, but the wisdom of fresh-air ventilation combined with the technology of purification can make it significantly easier to bear!

Photo by CDC on Unsplash

Why isn’t the fan making me cooler?

Why isn’t the fan making me cooler?

This is an odd post.  It’s about hitting an invisible barrier, one you don’t see until suddenly, things don’t work the way they’re supposed to.

When I see an article with the title “Fans Can Make you Hotter”, it’s an automatic click for me.  I rely on fans in every room of my home during most of the year to keep air circulating and help keep the air cooler.  How could fans ever make me hotter?

Well, we’re talking about extreme heat here: in an experiment, it was shown that fans used on volunteers in dry heat of 115 deg F heat index was more uncomfortable and detrimental than fans used on volunteers in humid heat with a heat index of 133 deg F.  In the first scenario, the lack of humidity in the circulating air caused their body temperature, strain on the heart, and thermal discomfort to increase.  In the hot and humid scenario, though, fans actually lowered body temperature and made them more comfortable.  

It’s not hard to understand why: think about a convection oven.  Above a certain temperature (104 deg F), dry air will start to impart its heat back to you, instead of whisking away heat from your skin.  Turning on a fan will only speed up the shift of hot air into the body, making you feel warmer, and potentially raising your body temperature to unhealthy levels.

In most parts of the US, dry heat like this is not a problem, but some areas of the west may certainly find it happening: garages, attics, and enclosed, unconditioned spaces quickly elevate in temperature and if there’s no humidity, be very careful of working there.  A fan in these conditions can hasten heat-related injury.  Here are some tips to stay safe:

  • If necessary to work in these conditions, wet clothing and make a wet headcovering so that the evaporation of water will cool you down.   

  • Take frequent breaks in a cool place (at least every 15 minutes)

  • Drink more water than normal and consume electrolytes

In this case it’s not the humidity, it is the heat!

Photo by Nathan Dumlao on Unsplash

From the Outside In: How to cultivate a healthy yard that will benefit your indoor air!

From the Outside In: How to cultivate a healthy yard that will benefit your indoor air!

Our yards say many things about our home and hopefully, they’re all good!  Because they surround our home, yards also directly impact our indoor air quality.  Here’s how to cultivate healthy air outside, because it will always permeate to the inside.

  • We wrote about the healthy heart benefits of green areas around the home.  To find the right trees and plants for your area, visit i-Tree Species.   Here’s some other tips for landscaping for indoor air quality:

    • Don’t plant shrubs right next to your foundation, so that mulch and soil will get air circulation and mold does not have continual shade and moisture to grow on surfaces.

    • Plants like lavender, basil, thyme, mint, lemongrass, chrysanthemums, petunias, marigolds and mosquito plants provide delicious fragrance and colors that also repel insects! (farmersalmanac.com)

    • Try natural pest repellants such as the ones we mention in this post, instead of toxic traditional repellants like malathion and pyrethoids.

  • Get the humidity right: if your yard is low-lying and frequently has standing water, it is very pest-friendly (mosquitoes, fleas and ticks all like water, not to mention mold!).  Consult landscaping companies to find the best solution for raising the elevation and/or draining water.

  • Whole-house generators are a popular addition to homes where there are frequent power outages or the possibility of extended outages (from severe storms or hurricanes, for example).  However, just like portable generators, they emit carbon monoxide (CO), carbon dioxide (CO2) and nitric oxide (NO), which can penetrate homes.  According to electricgeneratorsdirect, standby generators must be located at least 5 feet from windows and doors, and of course in compliance with local codes.   They can even be placed up to 18” next to the house where there are no windows or doors.  In our estimation however, they should be located farther from homes than the regulations require!  

  • It’s important that sewage lines are intact, so that liquids and gases stay where they should!  If they become damaged by cars or large equipment driving over them accidentally, call an inspector to view the lines with a pipe camera and assess repairs.

  • If you have a dusty road nearby, consider planting a row of trees or tall shrubs as a screen.  Bushy, hairy-leafed cotoneaster is a variety that stands tall above others in its ability to absorb particles and pollutants (theguardian.com)

  • Find a safe way to store garbage until it’s removed:  nobody wants to smell garbage, so it’s put outside where it can be “safely” stored until pick-up day.  But what about the smell?  You can try:

    • Finding a spot downwind where you can make a small hedge to shield the garbage from view and from direct sun

    • Making sure that the lid can be closed securely (bungee cords are great for this) so that critters do not get in.

    • Using an all-natural additive to remove smell and reduce flies and pests: Teraganix makes a number of microbial supplements for people, gardens, and yes even our garbage!  This one can be sprayed onto the garbage before closing the bag, or even poured down smelly drains.

  • Porches are typically cool, inviting places that say “come and relax”.  If you live near a busy freeway or road, however, pollution can travel farther than you realize, especially in the late night and early morning, traffic pollution drifts much farther than during the day. (LATimes.com)  This results from dropping temperature during the nighttime hours when the atmosphere traps car emissions, CO2, and other pollutants down near the ground. (yourairexperts.com)  During this time, it’s not good to be “porch-sitting”, but unless you have particle-filtering air purifiers inside (like a good HEPA filter), inside may not be much better. 

  • The sky is falling, the sky is falling!  If you live in a flight path or downwind of one, it’s probable that PM2.5 levels are substantially higher than in other areas.  Location may be unavoidable, but you can avoid trapping pollution next to  your house by not planting tall trees around the entire perimeter of your property or at least crosswind. Leave spaces for air to blow through and clear the pollutants.  

Interior home renovation may seem to be the most obvious way to increase interior air quality, but don’t overlook the yard outside, because what’s outside, eventually comes inside!

Is there mold hiding in your clothes?

Is there mold hiding in your clothes?

It has been one heck of a summer in the US!  More heat = more sweat, more sweat = more stinky wet clothes in the laundry hamper, and more wet clothes in the laundry hamper = more mold!   This is especially a problem with workout clothing or “outdoor work” clothing that get positively soaked with sweat.  My previous schedule of washing one time per week is not cutting it, because now I’m noticing that even after washing, my clothes are not smelling clean (I don’t use perfumed detergent).  Why can’t I get the mold out with just washing?

Mold is persistent.  Because we’ve been trained to save energy and that modern detergents and washing machines work well with cold water, I’ve basically gone to using cold water for all of my washing.  Cold water and detergent typically don’t remove mold, so after several cycles of letting them sit in my hamper, washing with cold water and drying, the smell intensified.  Something had to change!  This excellent article gives many non-toxic ways of getting rid of mold from clothing:

  1. First of all, the habit of leaving wet clothes in the hamper is not good.  If I can’t wash them right away, I need to hang them up to let the moisture dry out.
  2. If I can’t wash them right away, pretreating with a tea tree oil spray not only helps them smell better, but also kills the mold because tea tree oil is a fungicide!  Oregano Oil or Clove Oil will also work, depending on your fragrance preference.  Be sure to purchase pure oil without additives.  Here is how to make it: 
    1. Add one teaspoon of teatree oil to one cup of hot water; pour it into a spray bottle.  Shake the mixture.
    2. Spray the garment thoroughly, inside and out. 
    3. Let the mixture soak in for 10 minutes before washing.
    4. Pour the rest of the mixture into the washing machine or handwash basin.
  3. If you don’t like the smell of the essential oils (the smell does dissipate within a few hours), you can use hydrogen peroxide in a spray bottle (3% dilution works well) in the same way as the essential oils. 
  4. Borax has been around a long time for good reason– it is a good disinfectant and low toxicity (just don’t ingest it, inhale the dust or get it into your eyes). (ThoughtCo.com)  When mixed with hot water, it turns water into hydrogen peroxide. 
    1. Mix ½ cup of Borax with hot water in a large basin, stirring slowly until its fully dissolved.
    2. Soak the clothes in the mixture for at least 20 minutes.
    3. Pour the clothes into the washing machine with the mixture and wash for 2 cycles. 
  5. Vinegar and baking soda:  You’ve probably used this powerful combination before and know that it makes a foamy cleaning agent, except this time use it in separate wash cycles.
    1. 1st cycle: add 1 cup white vinegar to the detergent dispenser, with no other detergent.
    2. 2nd cycle: add ½ cup baking soda to the detergent dispenser and finish washing.
    3. Don’t ever combine vinegar and bleach!  This combination generates toxic fumes.
  6. Closets can be perfect for growing mold, because lack of air circulation can allow moisture to accumulate in the clothes, making them the perfect food source!  We posted an article “Can I avoid mold with JUST ventilation?” and the answer turned out to be oftentimes, you can.  Here are some ways to prevent mold from taking root in the nice clean clothes in your closet:
    1. Leave the closet door open.  If you are keeping your home below 60% humidity, usually this step alone can keep the closet from smelling musty–that first telltale sign of mold.
    2. Try not to pack clothing or boxes tightly together, again because air circulation around items is necessary to keep the humidity down in the clothes. 
    3. If you cannot keep the door open, try adding small dehumidifiers:
      1. DampRid is a brand name that makes a number of desiccant products that you can hang or set on a shelf or on the floor, but there are many comparable products.  Remember that water will need to be poured off, and the chemical absorbing the water will replaced, every so often.  This chemical is usually calcium chloride, which comes prepackaged in the replaceable refills.  Alternatively, you can make your own desiccant dehumidifier by purchasing silica gel or calcium chloride at the hardware store and placing it in small plastic bowls with the tops pierced (just don’t knock them over or the liquid may spill on the floor!)
      2. Small dehumidifiers can make a big difference in closets.  You can get a model to hang on a wall, or place on a shelf (just make sure there is sufficient space above and around it for air circulation).  The condensate container in these will also need to be emptied periodically (although the unit should shut off when full) so put a little reminder on your calendar to do that.  Here are some models that won’t break the bank:
        1. Eva-Dry ($22) makes several “wireless” models, which use silica gel desiccant which must be replaced every 20-30 days. This is a good option for smaller closets (up to 333 cubic feet) without a power outlet, and larger versions are available too.
        2. Eva-Dry also makes electric dehumidifiers; this model ($27) will need to be emptied every 3-4 days but it’s ultra quiet. 
      3. Many customers know that even higher humidity areas like bathrooms and closets can be kept mold free with the Mold Guard/Germ Defender.  It’s a powerful unit that emits a dense blanket of ions that can break apart/deactivate mold spores at the cellular level.  Perfect for spaces of 100 ft2 or under, this unit requires very little maintenance and can be purchased with optional charcoal filters.

The next time you put on clothing from the clean laundry and it doesn’t smell so fresh, it’s probably not you (or your deodorant), it may be mold.  Arm yourself with some natural anti-fungals like vinegar, baking soda, teatree oil, hydrogen peroxide or borax, and banish the mold from your wardrobe!

How to keep MILDEW out of your CLOSET

How to keep MILDEW out of your CLOSET

Closet doors are meant to keep closed, right?  Unless you are Martha Stewart, it’s likely your closet doors don’t stay open very long–if they close to begin with!  The problem comes when humidity and closed doors combine for a stinky problem: mildew and mold.

We sometimes think that mildew is a less toxic form of mold, but it is still mold nonetheless.  Mildew is a subclass of mold that exhibits a white or gray, flat, powdery growth, while the rest of the molds can get more fuzzy and colorful.  Both release spores, but unlike other molds, mildew doesn’t penetrate surfaces and grow into the materials it lands on (though it can still cause cosmetic damage). Instead, it grows on top of flat surfaces and often collects in places like cardboard boxes or your vintage leather jacket in the closet.  Not good!  (What is Mildew, Really? The Difference Between Mold and Mildew)

Since we know that mildew is a form of mold, we know that it needs several things to grow: a food source (ie. leather, clothing, and dust in general), moisture (even excess humidity) and air (although stagnant air is best because lack of circulation keeps humidity at surfaces high).  So, the best ways to keep mildew at bay in closets is to:

  • Clean out the dust and seal off any sources of dust

  • Keep the humidity down and ventilate

  • Store items for longevity and air circulation 

How the heck does dust get in the closet when the door’s closed?

Incredibly, some closets are like dust magnets.  If your closet is part of a tiled or vinyl floor area, dust bunnies can usually slide right under the door due to the slick surface.  If you have any penetrations in the ceiling (like a light bulb), then your closet may be part of a hidden circulation system where the framing in your walls conducts air currents throughout your home.  For example, closets near bathrooms may unknowingly supply air to the bathroom exhaust fan, if the fan’s ductwork is not sealed well in the attic or the lightbulb box is not sealed to the ceiling.  Then there are the closets that double as storage areas and HVAC equipment rooms.  If the HVAC unit is not sealed well, it just pulls air from the surrounding home into your closet.

  1. Seal

The way to keep out the dust is to seal these small air passages: at the ceiling, remove the light fixture and either use a caulk gun (less messy) or a spray foam can with a straw (very messy, be sure to cover everything!)  to seal the electrical box to the drywall.  If the closet is an upper story, you may be able to do it from above in the attic with less mess, and sealing all the ceiling penetrations may help with dust house-wide.  If you notice a lot of dust forming on the floor, it may be worth caulking the baseboards to the floor (if it’s tile or solid-surface) to seal that up as well.

  1. Clean 

Next, removing the dust should be part of a larger goal to store items properly so that cleaning will be easier and mildew will be less likely to form.  You’ll need a HEPA vacuum with brush attachments, and various storage containers.  If possible, empty the closet.  This will allow you to see all the walls and floor to see if there are any water leaks coming in that could be causing the mildew.  If not, use the vacuum to clean ALL the surfaces so you can get a fresh clean start!

It’s a great time to wash clothing and purge any items that you don’t use anymore by donating them.  Clean clothing is less likely to smell and deteriorate from body sweat and dust mites as well.

Stop right there!  If you had mildew in your closet before, you need to make ventilation changes to stop it from recurring.

  1. Ventilate/dehumidify

Mildew sometimes forms in closets because of lack of ventilation.  The great thing about moving air is that it lowers the moisture content of surfaces that come in contact with it.  If the air is not moving, the moisture content of surfaces tends to equalize with the stagnant air, and over time, mold is able to grow.  Also, if your closet is located on the corner or north side of a building, the insulation in the wall may not be sufficient to prevent warm house air from causing condensation on the cold wall.   Here are some tips:

  1. Refill the closet

Ok, you can start restocking the closet but remember this important point: maintain space between items so that air can freely circulate!  Don’t overstuff or compact items against the wall, either.  Wire shelving is great for maintaining circulation from top to bottom, too.

Storage containers matter, too–if possible, don’t use cardboard boxes because cardboard holds moisture, and it’s a favorite food for all kinds of pests: mold, roaches and silverfish like to eat it, and mice like to use it for bedding!  If you’ve cleaned and dried your clothing and excess bedding, packing them in clear storage bins is ideal so that you can easily see what’s in each.  For wool and moth-prone items, you can add cedar blocks to the bin to keep pests out.  These garment bags are great to keep dust off hanging clothes.

After mildew remediation, it’s important to check on your closet at least every few weeks until you’re sure that the changes are producing their intended effect: the ability to close the closet door without mildew taking root!

Photo by Annie Spratt on Unsplash

No-Demo Renos for Air Quality

No-Demo Renos for Air Quality

As of 2024, home renovation is still very popular in the US, but there’s been some interesting developments, such as “no demo reno”.  Eliminating demolition usually means less cost and less time--two very important commodities in renovation!  I’m waiting for designers to take it a step further to challenge themselves to redesign for air quality on a budget, to be judged by air quality experts.  Of course, you can spend thousands of dollars on the latest HVAC and purification systems, but you can also make a big impact with a lot less.  That’s what I’m talking about!

Whether you live in a sealed upper-storey apartment using forced air all the time or only use natural ventilation via windows and doors, furniture placement can affect the airflow and thus the air quality in your home.  According to a 2022 study, furniture layout is a key factor that affects the direction of airflow in a building. Different furniture heights can block or trap natural air or lower the direction of the airflow, thereby producing microscale positive or negative pressure.  It evaluated a naturally-ventilated school in Thailand which was located in a city which was plagued by high PM2.5 every January and May, mostly due to agricultural burning, and wind-blown dust. Under natural ventilation conditions, the direction of PM 2.5 distribution in the classroom was the same as that of the natural air. The air velocity and PM 2.5 concentration in the classroom were correlated positively, whereas the velocity increased, with the increasing concentration of PM 2.5. Adjusting the furniture layout of the classroom, as well as the size of the openings, affected the airflow and distribution of PM 2.5 within the classroom. 

Another study evaluated the pollution level of new furniture (VOCs).  Just by rearranging the furniture in an office with a forced-air system, there was a notable difference between the best and the worst ventilation effectiveness without any changes in the ventilation.  The key learning points were to: 

1) always try to place the pollution source (new furniture) as far away from your usual breathing zone (like sitting at the desk) as possible and, 

2) try to sit in the upflow field of the airflow.

If you aren’t trying to off-gas any new furniture, here are the rules that enable your HVAC to work at its optimum (How Furniture Placement Affects Your HVAC):

  • Make sure the furniture is not blocking any registers or vents.

  • Place furniture away from walls so that adequate airflow behind the furniture can prevent formation of mildew.  This happens when there is not enough air circulation (stagnation) to prevent humidity from saturating surfaces.  For more on how you can avoid mildew with better air circulation/ventilation, check out our article here.

  • Don’t block any windows or doors when placing large pieces such as couches or dressers near them

If you do need to obstruct a vent, try to use a deflector on the register so that air flow is directed to an open area.  They come in a number of shapes and sizes, even adjustable, to match your register/grille and desired direction of airflow.

How to visualize airflow in your space

There are professional engineering programs that can help “see” airflow, but they take quite a bit of measuring and input to get a simulation.  On the simple side, you can use the following to “see” airflow, and adjusting furniture position, window openings, vent positions and fan positions and speeds to modify air currents.

  • A helium balloon that has neutral buoyancy that “hangs” in the air below the ceiling will move with air currents (you can tie or tape a small weight onto it to adjust height).

  • A bowl of warm water with a chunk of dry ice (frozen CO2) will give off fog that moves with air currents (just be careful to use thick gloves when handling!)

  • Old-fashioned soap bubbles (you can make a wand by twisting a paperclip into a loop and use dish detergent and water) blown straight up into the air will tend to move in the direction of other air currents.

  • Candle flames/smoke may also show the direction of air currents.

  • Tape streamers or tissue paper in doorways to see which direction the air flows (tinsel also works).

  • Anemometers are fun devices to play around with, but unfortunately they usually only work very close to a vent or fan; they don’t move with minimal airflows. 

Windows: Don’t forget to pull back curtains or remove them altogether if you are using natural ventilation, because blocking windows with curtains blocks airflow and light!  Curtains are usually necessary for privacy, but you might consider trying sheer or loosely-woven curtains or a decorative fabric screen placed a foot or two inside the window, for more airflow.  If you want to open windows without letting in pollen or air pollution, check out our Nanofiber PureAir Window Screens and Window Ventilation Filters.

Fans: Portable fans can set atop furniture or even be hung on the wall to increase airflow.  Take the time to clean your ceiling fans and make sure they are running in the right direction (clockwise in the heating season and counter-clockwise for the cooling season).  

Even if you’ve lived in a space for a long time and think you have tried “every possible arrangement” of furniture, the act of rearranging furniture every so often is not futile for the following reasons (Rearranging Furniture Could Help You Use Space More Effectively and Give You a Mental Boost):

  • Moving furniture will expose dirt, dust and allergens so that you can clean under it, improving indoor air quality.

  • Moving it may force you to remove or store clutter that also collects dust

  • Moving furniture could expose other air quality problems like hidden leaks or mildew, pet stains or pest infestations

Better furniture arrangement can help you to feel less stuffy and more energetic, even if the airflow changes are minute.  Just a few last tips before you get busy redesigning a room: 

  • remember to use a measuring tape first before trying to move heavy or large furniture to a new spot! 

  • Have your cleaning supplies at the ready to vacuum up dust, cobwebs, pet hair, etc..

  • Call on your friends not only to help with the moving, but also to lend ideas.  

  • If you don't have plants, consider adding a few strategic plants as natural air purifiers (and a pop of color!)

  • Plugging in a small air purifier with a fan like the  Germ Defender or Upgraded Air Angel Mobile will freshen the air and add airflow on a micro scale.

Photo by Nathan Fertig on Unsplash

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