What is the Ideal Indoor Humidity Level?

Presidential Heating & Air Conditioning

Gaithersburg HVAC Contractors


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Humidity Level Inside Your Home

a large living room with black and gray furniture as well as a good indoor humidity level so that the homeowners can consistently feel comfortableThe level of humidity in your home is a big factor in the comfort level. Not only is proper humidity important for your comfort, it is important to your health. The Environmental Protection Agency notes indoor air quality is a significant health threat. If the indoor humidity level is too high, you can have problems with mold and allergies, but if it’s too low, you can experience dry skin and annoying static electricity.

Having a “just right” humidity level makes your home so much more comfortable. So what is the Goldilocks level of humidity? First, understand that humidity is the amount of water vapor present in the air “expressed as a percentage of the amount needed for saturation at the same temperature.” The capacity of the air to hold water changes as the temperature goes up or down. A humidity level no higher than 50% is the best as a general rule of thumb, but the best level depends on the temperature outside.

The Ideal Humidity Level in the Summertime

Summertime temperatures in many regions of the United States bring uncomfortably high levels of humidity. High humidity can wreak havoc on your home and on your health.

The cooler indoor air and the hot outdoor air will cause condensation to form on your windows. Eventually, pooling condensation can rot your window trim. At certain levels of humidity, you will have dust mite infestations. Dust mites are a health issue especially for people with allergies.

A high indoor humidity level can also cause your paint and wallpaper to peel, your wood floors to cup and buckle, and your furniture to become mildewed. It can even affect the structure of your home, invisible to you until you need major repairs. High indoor humidity also creates an environment that fosters the growth of bacteria, viruses, fungi, mold, and mildew, which in turn can lead to unhealthy indoor air quality. These microorganisms can create serious health problems for people with severe allergies or asthma.

High humidity indoors makes you feel hot and uncomfortable. You will run your air conditioner more, when in fact the real issue is the humidity is too high.

dehumidifier installed by an HVAC contractor that is sitting next to a sofa in order to optimize the indoor humidity level for a small home in Gaithersburg, MDThe easiest way to combat these destructive high levels of humidity indoors is to use a dehumidifier. You can purchase a small portable dehumidifier inexpensively and operate it in the summer months. Some portable dehumidifiers can be configured so that they drain continuously, but care should be taken to ensure that the drainage is not impeded. Other portable dehumidifiers do not drain continuously. These require manually emptying the water bucket when it is full, or the machine automatically shuts off.
In short, portable dehumidifiers are helpful in lowering indoor humidity but only if they are properly maintained.

With a dehumidifier, you can keep the humidity level below 50%. (To further reduce dust mite issues, remove carpeting and use anti-allergen bedding). Ideally, the indoor summertime humidity level should be between 40 and 50%. Portable dehumidifiers do not offer the ability to precisely regulate the humidity levels. Nonetheless, even a portable dehumidifier will make the indoor air more comfortable, enabling you to run your air conditioner less.

The Ideal Humidity Level in the Wintertime

Outdoor humidity levels are lower in winter. Running your furnace further reduces the humidity indoors. As a result, the air inside your home is drier in winter than in summer. If the indoor air is too dry, you will have static electricity and dry skin. Frequent nosebleeds, chapped lips, sinus infections, and sore throats are symptoms of too much dryness. It can cause your wood floors, door and window frames, and your furniture to splinter and crack. It can aggravate asthma and allergies. You may feel cold because the dry air is robbing moisture from your skin, causing you to turn the heat up even more.

To achieve the optimum indoor humidity level, many homeowners use humidifiers. Even in humid regions of the country, a humidifier in the winter months makes the indoor air more comfortable. You will feel warmer without turning up the heat. With a humidifier, however, you need to adjust the humidity level as the outdoor temperature changes. If the indoor humidity gets too high, condensation will form on your windows. Excessive moisture during bathroom showers and baths can develop as well.

woman adjusting her brand new dehumidifier in order to lower the indoor humility level of her home and create optimal indoor air quality for her kids and dogTo avoid condensation issues, keep the humidity level at or below 40% when the outdoor temperature is 20 to 40 degrees Fahrenheit. Lower the humidity level to 35% or less when the outdoor temperature is 10 to 20 degrees Fahrenheit.

How Best to Regulate the Humidity Levels in Your Home

As mentioned above, you can control the indoor humidity level by having an experienced HVAC contractor install a whole-home humidifier and dehumidifier. These systems will automatically work with your home’s HVAC systems to add or remove moisture from the air as needed.

Below are some guidelines for optimal humidity levels based on the outdoor temperature.

When the outdoor temperature is…

… over 50˚F, indoor humidity level should be less than 50%.
… between 20˚F and 50F, indoor humidity level should be less than 40%.
… between 10˚F and 20˚F, indoor humidity level should be less than 35%.
… between 0˚F and 10˚F, indoor humidity level should be less than 30%.
… between -10˚F and 0˚F, indoor humidity level should be less than 25%.
… between -20˚F and -10˚F, indoor humidity level should be less than 20%.
… at -20˚F or lower, indoor humidity level should be less than 15%.

Keeping the humidity level balanced in your home mitigates static electricity in the winter, protects your wood floors and furniture against cracking, reduces unhealthy contaminants such as mold, mildew, and bacteria, and makes your home more comfortable overall.

Contact an HVAC Technician For More Information

A whole-home humidifier and dehumidifier can make your home healthy and comfortable. If you do not already have one, consider having one installed. If you already have one, make sure it is operating at optimal levels with regular routine maintenance. Contact the licensed professional HVAC technicians at Presidential Heating & Air, with experience in home humidity control for more information and to schedule an evaluation.

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