What do a bad hair day, a foggy mirror, and a triple-digit heat index have in common? Many times, they can all be blamed on humidity — an easy scapegoat, especially during the summer months.
But what many people don’t realize is how vital correct moisture levels are, not just to our home comfort, but to our indoor air quality and overall health. From seasonal allergies to wildfire smoke, many conversations about indoor air quality focus on the pollutants in the air we breathe. But humidity plays an important role in how these particulates make their way around our homes, and into our lungs — or not.
Here’s a look at what humidity really is, four ways it impacts our health and indoor environment every day, and easy ways you can monitor and manage humidity at home to optimize your indoor air quality.
What is humidity?
First of all, it’s important to learn what humidity really is. Most of us understand that humidity is a measurement of moisture in the air. This is measured in two different ways: absolute and relative humidity.
Absolute humidity is the total amount of water vapor in a given volume of air, and is measured in grams per cubic meter.
Relative humidity — which we often hear about on weather reports — measures the ratio of absolute humidity to the maximum possible humidity at the same temperature. For example, 50% relative humidity means the air is holding half of the moisture it could at that temperature.
Ken Nelson, indoor air quality expert and Group Sales Manager with Panasonic Eco Systems, says having some moisture in the air is a good thing, and 30% to 50% relative humidity is ideal for most indoor air quality environments. “Most people consider this comfortable,” he says. “If you go below 30%, you start to see effects in your home and on human health.”
Your home comfort & energy efficiency tie back to humidity
Thinking about humidity in terms of weather conditions makes a great segue back to your home comfort. In the same way people talk about a “dry heat” or a high “feels like” temperature on a humid day, those principles apply in your own home as well — and can affect how much you spend on heating and air conditioning.
If your indoor moisture is too high during warm weather, you and your family are going to feel uncomfortably warm. And what do you do when it’s too hot in your house? Kick up the air conditioner, of course! Likewise, high moisture on a winter day can feel colder, which could have your furnace working overtime. The Department of Energy says avoiding these high humidity situations can help keep your home more comfortable — and your energy bills lower.
How humidity affects your health
To Nelson’s point, maintaining the right level of humidity is crucial for a healthy and comfortable living space. Low humidity can cause dry skin and eyes, bloody noses, chapped lips, and other issues, making you more prone to colds and respiratory infections. On the flip side, high humidity can lead to a stuffy, uncomfortable environment, making it harder to breathe and potentially exacerbating conditions like asthma and allergies.
Not only can humidity alone affect your health — it can serve as a carrier for other indoor air contaminants like viruses and bacteria.
“When we look at moisture in the air, we look at “ballistic” moisture that’s heavy enough to land on surfaces, and “buoyant” moisture that’s light enough to stay aloft and travel longer distances,” Nelson says, “Both of these can be vectors for spreading germs.”
In terms of your health, Nelson says ballistic moisture could spittle from someone’s mouth that lands on surfaces, hands, or skin. If that person has a cold or other illness, their germs could be transferred to whatever surface the moisture lands on. While it's less likely to inhale ballistic moisture, Nelson says smaller buoyant particles can travel much farther and easily enter your lungs.
“Buoyant particles like respiratory emissions can stay aloft for as long as 16 hours,” Nelson says. “Whether someone in your home has the common cold or something more serious, it’s easy to see how illnesses can spread when you know that germs and bacteria can move around your house for so long.”
Humidity’s impact on mold and mildew growth
Staying in that sweet spot of optimal moisture levels also helps stave off nasty mold and mildew growth in your home. Mold will grow in any environment that has moisture, oxygen, and an organic food source. We often see this happen in damp bathroom environments, but your kitchen, crawl space, and HVAC system can also harbor these pests if humidity isn’t under control.
In a humid home, mold and mildew growth can cause or exacerbate respiratory issues, allergies and asthma for people living in the environment. Moreover, it can cause damage and deterioration of the surfaces in your home by using them as a food source. Excess humidity can allow mold to grow on drywall, wood beams and other materials that then lose their structure and strength over time, causing damage to your home.
Protecting your belongings from humidity
In addition to the structure of your home, your belongings are also at risk of damage by moisture — both too high and too low. In the same way self-storage companies prioritize climate control for storing your belongings, keeping your humidity controlled at home is essential for the same reason. Relative humidity over 60% can allow mold, mildew, rust, paper rot and mites to thrive, causing damage to your home, furnishings and belongings.
But low humidity can be damaging as well. Nelson says, “if you go below 30% relative humidity, a lot of manufacturer warranties in your home start to come apart. Your wood floors, windows, cabinets and other items can start to buckle or check.”
Tips for managing humidity at home
When so many elements of your home, health and personal comfort hinge on the amount of humidity in the air, understanding how to manage humidity at home is essential. In many cases, this comes down to having the right equipment in place, as well as understanding where moisture is coming from in the first place.
Humidifiers & dehumidifiers: The common appliances can be installed as whole-home units in line with your home’s HVAC system or used as standalone units for moisture management in individual spaces. Humidifiers add moisture into the air during dry spells, while dehumidifiers remove it when relative humidity gets too high.
Moisture & occupancy sensors: Especially useful in bathrooms, moisture and motion sensors are easy, set-it-and-forget-it tools that can help keep your home humidity in check. Moisture sensors work by automatically turning on your bathroom’s exhaust fan once humidity reaches a certain level, such as after a shower or bath. Occupancy sensors will do the same when they’re triggered by motion in the room. Having your ventilation fans kicking on periodically throughout the day will help ensure moisture is exhausted out of the home regularly.
Range hoods: Cooking is a common source of moisture in the home, and is also a great example of buoyant moisture that can travel long distances. For example, moisture particles carry aromas around the home, making it possible for the scent of brewing coffee or baking bread to travel into every room of your house and all the way upstairs. Keeping your range hood running regularly can help pull that unintended added moisture out of the air.
Monitoring moisture sources
If cooking is a surprising source of home moisture, don’t forget that you and your family members are too! “As humans, our lungs actually operate at 100% humidity, and breathing puts moisture into the air around us,” Nelson says. “In eight hours of sleep a person has the potential to outgas 1% of their body weight in moisture!”
Nelson says having multiple people in a small footprint, such as children or couples sharing a bedroom, the increase in humidity could call for a dehumidifier to maintain a comfortable space.
It's important to monitor other sources of moisture as well. Be sure to seal gaps and cracks around your foundation, windows and doors to keep excess humidity from finding its way inside. Quickly fix leaks from pipes or roofs to avoid unnecessary water damage and associated moisture issues from growing unchecked.
Keeping an eye on humidity
Managing humidity is a key factor in maintaining a comfortable and healthy home. By paying attention to your indoor humidity levels, you can positively impact your family’s health and comfort, prevent mold growth, protect your home and belongings, and optimize energy efficiency. Visit Panasonic's Green Living blog for advice on healthy indoor air quality. Explore best-in-class solutions to update your home’s ventilation system for the best results.
