Whether you live in a warm or cold climate, every homeowner should make it a priority to manage the humidity levels in their home. Not only does your home humidity level affect your comfort and health, it also can affect the “health” of your home. This article is the first in a three-part series. Here we provide an overview as to why humidity levels matter. Watch for the subsequent articles that will dive into humidity levels that are too high and low, respectively, and how to solve the problem.

What is relative humidity?

Humidity is the amount of water vapor present in the air. When we talk about humidity in the home, we are talking about relative humidity. Specifically, it is relative to the temperature, because the air can hold more water during warmer months than in colder months. This is important because maintaining ideal humidity during summer is different than maintaining ideal humidity in winter. The ideal relative humidity level for your home is between 40 and 50 percent, especially if you have hardwood floors. If you don’t, going up to 55% humidity may suit you. Anything outside these percentages can impact your:

  • health
  • comfort
  • cost to cool or heat your home
  • home’s structural integrity

Humidity Setting for Summer versus WinterAmount of water in air at various temperatures

Since warmer air can hold more water, humidifier settings can be counter-intuitive. In other words, your humidity setting for summer will be higher than your humidity setting for winter, even though we think of winter as drier. It is drier, because the air holds less moisture, but because it holds less moisture, our effort to put moisture in it changes. Hunker tells us,

When outdoors temperatures are between zero and 10 degrees Fahrenheit, set the humidifier to maintain 25 percent relative humidity. When the temperature is between minus 10 and zero degrees, set the humidifier to 20 percent.

Humidifier settings chart summer and winterIf you live in a seasonal climate, in the summer, you’ll need to work to keep your relative humidity low. It will want to creep up, especially if humid or rainy outside. Keep it below 50%. If you get above this, you can turn your air conditioning to a cooler temperature, or even shut your humidifier off. Not making this change may effect the proper functioning of your central air conditioner.

In the winter, then, your challenge will be the opposite… to not let your relative humidity get too low.


Signs of problems with your humidity level

If you see frequent foggy windows, especially for temperatures above zero or ten degrees Fahrenheit (-18 to -12 Celsius), you may have a concerning level of relative indoor humidity. Even worse, moisture will build-up on walls or ceilings. Even in modern homes, this can be due to inadequate ventilation, causing internal moisture build-up from cooking and bathing (Adams Roofing Professionals). Lowering the humidity in your home at this point is crucial to avoid mold growth and structural damage.

You can test your humidity levels with a hygrometer that you can pick up at your local hardware store. There are plenty of in-home tests you can do, too. One trick is to place a few ice cubes in a glass, add water, stir and wait three minutes (don’t perform in the kitchen). If moisture does not form on the outside of the glass, the air is too dry and you may need a humidifier.

What happens if relative humidity is too low?

For the structural integrity of your home, too-low relative humidity is the better of the two imbalances. However, if humidity levels are too low in your home, you may run the risk of dry and itchy skin, catching a cold, and possibly ruining your wood furniture. As we run forced heat during the winter months, air dries out, leading to uncomfortable environments. You can invest in a portable humidifier, but you should also have your home’s humidifier – part of your HVAC system – checked annually.

If you suspect your home’s humidifier is not working properly, you may have to replace old humidifier pads/filter. Old pads can have months of build-up, which is impossible to clean off after long-term wear and tear. Other problems that can prevent your humidifier from working include clogged valves, bad motors, and broken thermostats. The easiest way to prevent your humidifier from breaking is to replace the filter annually, and to also clean the insides thoroughly once a year, which will destroy all germs and rust.

When and why is lowering humidity in-home crucial?

On the other hand, you can also have relative humidity levels that are too high. High humidity levels can cause mold/bacteria growth in your home, stuffy conditions, and overall discomfort. Mold growth is a big health issue, especially for people with asthma or mold allergies. Likewise, mold can damage your home, cause unpleasant odors, and impact your ability to sell it. The summer months can pose high humidity level issues. In some cases, a de-humidifier can be a solution for lowering humidity in your home.

Seasonal humidity can affect indoor home comfort, so managing your in-home levels can make spending time indoors more enjoyable. You can also help prevent health issues and damage to your home. Watch for our next article on how to tell if your home humidity is too high, and what to do about it.


Relative humidity chart license: https://en.wikipedia.org/wiki/GNU_Free_Documentation_License
credit: Greg Benson