Tag Archives for " air circulation "

Keeping Your Vacation Home Fresh

It doesn’t matter whether your “vacation home” is a pull-behind trailer, or a luxurious condo, or a humble cabin in the mountains:  when you “get away” to a relaxing place, you don’t want to spend your precious vacation time trying to figure out how to get musty smells out or remove mold from the linens because the climate inside suffered while you were away.  Here are our tips to make it welcoming and low-maintenance!

First of all, humidity is the most important factor you’ll want to control in order to keep out mold, and you’ll want to keep the humidity under 60% all the time.  If the outside climate humidity rises over 60%, that climate will come inside and settle into soft surfaces, making them a perfect habitat for mold growth. You can only control humidity inside effectively by having a tight envelope, which means sealing up passages where outside air can penetrate in.  If no one will be living there while you’re away, you won’t need fresh-air ventilation, so make your get-away home as tight as possible by sealing windows, doors, attic doors, and other penetrations.  

Also, remember that relative humidity and temperature are closely linked.  For example, if you leave an air conditioner set on 82 degrees and the humidity rises to 80%, you may be at risk of mold forming in less than 2 weeks!  (If you’re wondering how that calculation came to be, check out this fun dew point calculator.)  In addition, relative humidity in a space will increase as temperature is lowered.   Air conditioning will naturally take some of the humidity out of the air, but there are a number of factors that can allow humidity to remain high even when your air conditioner is on. 

Here are some options to keep the humidity under control while you’re not there:

• If you have wi-fi available in your vacation home, now’s the time to take advantage of technology that can pair with existing units like mini-splits, window or portable air conditioners to enable you to monitor climate and control them remotely.  Cielo is a company that has a number of products that can help you maintain the right humidity and temperature remotely. 

• Alternatively, if you do not have wifi or app-enabled monitoring, you’ll need to choose a temperature for setting your air conditioner.  Although it’s tempting to set the temperature just under the temperature of melting plastic (haha) to conserve energy, don’t do it!  Setting the thermostat as high as 85 degrees can cause short run times and not allow the air conditioner to remove enough humidity from the air, creating an atmosphere for mold growth.  (No, You Shouldn’t Set Your Thermostat to 85F.  Here’s Why.)  For that reason, it’s ok to set it 7-10 degrees above the temperature you normally keep it while you’re staying there IF you also take into account the outdoor temperature and humidity.  There’s no magic formula for determining this ideal energy-saving-yet-mold-preventing temperature setting, but think about it: if your vacation space is in a hot, humid climate like the southeast US, you’ll want to set the maximum indoor temperature lower than the average outdoor temperature to make the air conditioning come on often enough to remove humidity.  

• Thirdly, if you don’t have a humidity control setting on your air conditioner, or even an air conditioner at all, it’s best to purchase a dehumidifier with a humidistat and set it to 60% maximum humidity.  This will ensure that humidity is being controlled, no matter what temperature the interior rises to!  Think of this dehumidifier as insurance against mold: if your air conditioner was to stop working, the dehumidifier can still keep your space mold-free if it’s suitably sized for your space.  Check out our article on different types and sizes of dehumidifiers, and be sure to set up a portable dehumidifier with a drain into a lower tub or sink that condensate can safely drain all the time.

• Leave doors to rooms and closets open for best air circulation.  Just like air purifiers, portable dehumidifiers cannot reach behind closed doors.  

• Use ceiling fans in rooms and portable fans elsewhere to keep air circulating while you’re away, which will reduce the water content in all your furnishings by evaporation.  ““Evaporation increases the humidity of the atmosphere that immediately surrounds the liquid. This humid air takes some time to dissipate into the rest of the atmosphere. The presence of a breeze, a powerful wind, or some other form of air circulation can speed up this process and make the environment of the liquid less humid. Therefore, by decreasing the humidity of the liquid’s surrounding, a powerful breeze or wind can increase the rate at which the liquid evaporates.” (Factors Affecting the Rate of Evaporation)  This is why disaster restoration companies use powerful fans to move air over wet surfaces, increasing evaporation and removal of water.  With less water in your furnishings, the chance of mold growth is reduced.   You can even add air circulation to any space that has a light socket, such as closets and pantries, by removing the light bulb and screwing in a light socket fan (which come in different designs with exposed or enclosed blades).

• Make sure your air conditioning and dehumidifier drains are clear and a clean air filter is in place before you leave!  Many homeowners have come on vacation to find their air conditioner or dehumidifier drain pan overflowing and dripping onto ceilings, floors, and other inconvenient places–what a mess that can also turn into hazardous mold!  As a homeowner, make sure to check these drains and change the filter several times during the air conditioning season, or arrange for someone to do the same while you’re away. 

• Window air conditioners need deep-cleaning sometimes.  If a musty smell is coming from the air conditioner when the fan cycles on, then you’ll know that dust has infiltrated the cooling coils, absorbed moisture, and is nourishing mold growth.  Check our article on how to deep clean it and restore the fresh smell.

• If you can, shut off water at the main valve to avoid any possible leaks, and switch off the breaker to the hot water heater if it’s electric (turn off gas if it’s gas).  This will avoid water leaks under sinks, which can make a nasty moldy mess!  If you don’t do this, at the very least shut off water to the washing machine, because burst water hoses at the washer are the single largest cause of home flooding.  (Leaving the House for 3 Days or 3 Months? 5 Must-Dos Before Your Trip)

• Bipolar ionization units like our Germ Defenders, Mobile Air Angels and Whole Home Ionizers are a great way to keep mold away too.  At the very least, plugging a Germ Defender into the bathroom will send out ions to kill mold spores in this small space where air circulation can be a challenge.

• Leaving a portable HEPA filter with activated carbon running is not a bad idea, either.  Activated carbon will help avoid that “musty” smell.  According to firesafeliving.com,  “plug-in” scent devices are not a fire hazard if you leave them plugged in while you’re away, but we at HypoAir don’t recommend them because a) many plug-ins use toxic chemicals like phthalates and formaldehyde, and b) the freshener will dry out before you return anyway, leaving an appliance running on your wall.  What’s better: make your own reed diffusers with your favorite essential oil (or combination of oils) and place them throughout your space for a safe, no-mess fresh scent!

These extra steps may seem to take more time on those days you’re packing up to leave your vacation home, but when you come back to a home that is ready for relaxing as soon as you open the doors and windows, it will be worth it!

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.

2. 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.

3. 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:

• Add a closet-sized dehumidifier or desiccant bag (see our article here for recommendations)

• Add a small fan to the light socket so air can continuously circulate

• If there is a gap at the bottom of the door, install a fan in the top of the door to pull air through the closet and exhaust it at the top (or better yet, through the opposite wall).

4. 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!

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.