RELATIVE HUMIDITY

The humidity—or amount of water vapor in your home—has a big impact on both comfort and health. When humidity is too high, the air can feel hot and stuffy, creating ideal conditions for mold and other biological growth. When it’s too low, the air can feel cool and dry, irritating your airways and increasing the risk of respiratory infection. The good news is, with proper management, you can control the humidity levels in your home, and bring them into balance. Your contractor can help you problem solve and get your home to the best version of itself.

WHAT THE EXPERTS SAY

“The influence of relative humidity on the abundance of allergens, pathogens, and noxious chemicals suggests that indoor relative humidity levels should be considered as a factor of indoor air quality. The majority of adverse health effects caused by relative humidity would be minimized by maintaining indoor levels between 40 and 60%. This would require humidification during winter in areas with cold winter climates.”

National Library of Medicine

“Sometimes, humidity or dampness (water vapor) in the air can supply enough moisture for mold growth. Indoor relative humidity (RH) should be kept below 60 percent — ideally between 30 percent and 50 percent, if possible. Low humidity may also discourage pests (such as cockroaches) and dust mites.”

Environmental Protection Agency

(EPA)

“Moderate indoor relative humidity (RH) levels (i.e., 40%–60%) may minimise transmission and viability of some viruses, maximise human immune function, and minimise health risks from mold…”

National Institutes of Health

(NIH)

WHY TESTING FOR RELATIVE HUMIDITY IS IMPORTANT



Controlling biological growth

Ideally, indoor humidity should remain under 60%, and the healthiest range is typically 30–50%. When humidity rises above this range, it can lead to biological growth in your HVAC system and other areas of the home, which can increase allergen levels.



Paving the way for infection

In addition to making your home more uncomfortable, humidity that’s too low can leave you and your family prone to infection. Low humidity dries out moisture-dependent tissues, making eyes, skin, and airways more vulnerable.

Sterling Chart AIrAdvice - gradient on background with orange-01

RECOMMENDED ACTIONS

A man in a ball cap changing an air filter. Image generated by CoPilot AI.

Install humidifier and/or dehumidifier to closely control the humidity levels in each room.

A dirty male hand, holding a paintbrush, is spreading caulk over a house air duct joint with a paintbrush.

Inspect ductwork; seal and clean as necessary. Talk to your contractor about how to best accomplish this in your home.

Install a non-ozone UVC lamp over the AC coil to prevent biological growth. Your contractor can help you find the perfect fit for your HVAC system.

AIRADVICE PROTIP:



A key component of home health is controlling relative humidity (RH) to prevent biological growth, such as mold and mildew. Proactively managing moisture is far more effective and less costly than dealing with a full-blown mitigation.

WHAT ELSE DO WE MEASURE?

Interested in learning more about how to improve home health, safety, and comfort? AirAdvice tests for 7 different parameters in the home with our top-of-the-line monitor. Our monitors are designed and maintained to produce clear and accurate results, giving you a clear picture of the state of your home’s air. Scroll down to see the other things we test for in a home.

Temperature

The National Institutes of Health (NIH) states temperature is linked to our health, well-being, and productivity. Read more about how optimizing the temperature can improve the comfort in your home.

Particles

Particulate matter (PM) is a microscopic mixture of solid dust particles and liquid droplets found in the air, invisible to the eye. The smallest particles pose the greatest health risk and can get into the deepest part of our lungs and into the blood stream. Read more about how to prevent the build up of particles in your home.

Formaldehyde

Formaldehyde is a chemical found in many household products and building materials, and is also produced by combustion. While formaldehyde is common in homes, it can be harmful to your health. The CDC says the cancer risk is low from typical indoor formaldehyde levels. Experts recommend keeping formaldehyde levels as low as reasonably possible in your home.

Carbon Dioxide

Carbon dioxide (CO2) is a gas we exhale. It builds up in the home when there is no fresh outdoor air, impacting health, comfort, and performance. Read more about the effects of high levels of CO2 in the home, and how it can be remedied.

Volatile Organic Compounds

Volatile Organic Compounds (VOCs) represent a broad category of chemicals that are present in numerous products we use to build and maintain our homes. Once these chemicals are in our homes, they are discharged or “off-gas” into the indoor air we breathe. They may or may not emit odors, so smelling is not a good indicator of health risk.

Carbon Monoxide

Carbon monoxide is gas that has no odor, taste or color that comes from burning different fuels. It can build up to deadly levels in the home, especially when appliances and engines aren’t well ventilated or vented. Read more about how to prevent this build up in your home.