Managing Your Home’s Humidity

Relative humidity (RH) is how much water vapor is in the air. If the RH level is too high (above 65%), the air is so saturated that the air cannot cool the sweat from our bodies, making us feel uncomfortable, sticky, and swampy. If the RH level is too low (below 30%), the air feels cooler than the temperature and our sweat cools our body very quickly. That’s why fog, which is a low RH, feels chilly on our skin.

Dew point is the temperature the air needs to be cooled to in order to reach a RH of 100%. If the water in the air continues to cool, it transforms into a liquid or gas form, such as dew droplets, fog, or rain. The dew point directly affects how comfortable it feels outdoors. The higher the dew point rises, the greater the amount of moisture in the air, which feels muggy and swampy. A dew point around 55 is comfortable, but higher than 65 and the air will feel heavy, thick, and oppressive.

Why Humidity Matters
For many homes, the ideal humidity level lies between 30% to 60%, but every person has their own preferences based on their location and lifestyle. Humidifiers and dehumidifiers help to keep indoor humidity at a comfortable level for people, but also keep interior structures like drywall and lumber dry. Soggy drywall leads to deterioration and mold, so it is exceptionally important to make sure your home’s humidity stays within a comfortable range.

High indoor humidity (too much moisture) causes the air to feel muggy; makes for uncomfortable sleeping conditions; and promotes the growth of mold, mildew, fungi and other harmful bacteria and viruses.

Low indoor humidity (too little moisture) causes discomfort and dry skin; allows cold and flu viruses to spread more quickly; and can even damage your home’s wood infrastructure (floors, doors, windows) and furniture. 

• Try a hygrometer. Instead of trying to guess or assume the humidity levels of your home, use a hygrometer for fast, easy, and inexpensive certainty (the most basic device can start around $8 and range up to $50 for additional features). Available at any home improvement store in either a digital or analog model, the best hygrometers sense and report the amount of humidity in the air in any given area. This is especially helpful in food or wine storage, or when housing other humidity-sensitive items, such as cigars, documents, animal tanks, and plants.
• Find your ideal indoor humidity levels based on the season and outdoor temperature. For most people, the comfortable range for RH in a home is between 30 and 60 percent, though to help control mold, it is best to keep it around 40 to 50 percent. Monitor the RH levels during different times in the year, such as after the first frost and during the rainy spring season, and adjust your home’s levels as needed using a humidifier or dehumidifier.
  • While often confused for one another, a humidifier and a dehumidifier have different jobs in helping control the RH levels. A humidifier adds moisture into a space or room through mist and is most often used in winter months to keep skin and sinus passages from drying out. A dehumidifier removes excess moisture in the air, helping prevent mold or mildew and helping alleviate allergies and headaches in the summer.
• Manage your preferred humidity levels throughout the year by maximizing the household’s air control systems. 
  • Your air conditioning system isn’t just for the hottest days—AC can also decrease indoor humidity by keeping the air temperature stable. You can also turn on exhaust fans, make sure your HVAC filters are clean and regularly replaced, and invest in a dehumidifier.  
  • To increase indoor humidity, use your heating system to help raise the level of moisture in the air, because warm air holds more moisture. You can also add moisture by allowing the steam from a shower to escape the bathroom, adding plants to your home, making sure your door, windows, and weatherstripping are all sealed properly, and investing in a humidifier.

If you want the guidance and knowledge of a trusted expert, talk to your local Rheem Pro Partner to learn more about optimizing your heating and cooling home solutions. New, energy-efficient products offer precision technology and smart home connectivity to make maintaining your home’s preferred conditions a breeze, no matter what the outside weather throws your way.