How Humidity Impacts Comfort
Humans naturally cool their body though perspiration; as sweat evaporates from the skin it removes heat and cools the body down. Likewise, reducing and maintaining the Relative Humidity (RH) in your home will increase the level of comfort. As property development becomes more energy efficient (tighter envelopes, thicker insulation, higher efficiency appliances, and utility-bill-friendly windows), an escape route for added moisture has become essential.
The indoor comfort of your home/property can easily be improved by controlling the amount of moisture in the air. High humidity makes air feel warmer than the displayed thermostat temperature. Your home/property will feel most comfortable, ideally, at humidity levels between 30 – 50% RH. High humidity levels will also make it easier for mold to reproduce, and once mold begins to grow it can appear almost anywhere.
Causes of High Indoor Humidity
- Bathing | people and pets
- Cooking | boiling water, steaming vegetables, making coffee
- Cleaning | mopping floors, scrubbing bathrooms, wiping countertops
- Laundering | washing and drying clothes
- Other | breathing, perspiration and watering plants
Balancing Thermal Comfort
Humidity will affect the comfort of your home/property year round, and indoor humidity management for every season will increase thermal comfort. Simply put, thermal comfort is the feeling when someone is not too hot or too cold.1 Many people associate thermal comfort directly with air temperature, but there are a variety of factors to consider including movement, clothing, and personal preference. ASHRAE 55 defines comfort as “combinations of indoor space environment and personal factors that will produce thermal environmental conditions acceptable to 80 percent or more of the occupants within a space.”2 Since thermal comfort is subjective, personal expectations have the largest effect on comfort.
People have an ideal range of temperature and humidity in which they feel most comfortable. Proper dehumidification during summer months, will allow the indoor temperature setting to be raised which will directly offset the cost of energy consumed to remove moisture; indoor air feels cooler with less humidity. For comfortable indoor humidity during the summer months, interior relative humidity should never exceed 60%. (See Figure 1, below) It is still important to maintain RH during cooler months because cold air holds less moisture before it becomes saturated. This means in winter months the interior relative humidity should be kept as low as possible, but always above 30%.
Once moisture enters a building, effort is required to remove the added moisture
Supplemental dehumidification will compliment the capabilities of any cooling system to keep indoor humidity levels consistent. In 2012 Innovative Dehumidifier Systems designed a hands-free dehumidifier to help resolve the problems associated with high humidity in multi-family apartments. Since creation, the benefits have been applied to a range of properties including student housing, military homes, senior living, hotels, historic buildings, luxury condominiums, and more. The wall mounted dehumidifier can remove up to 29.5 pints of moisture per day in smaller spaces. IW25 IN Wall Dehumidifier/On Wall Dehumidifier includes a lock-out control system; a digital RH control is concealed behind a tamper-proof cover, eliminating tenant’s control of dehumidification. Innovative Dehumidifier Systems offers hands-free indoor humidity management, with hands-on customer service.
Why Mold Growth is a Problem
Sources:
- Thermal Comfort https://www.sciencedirect.com/topics/earth-and-planetary-sciences/thermal-comfort
- Exploring thermal comfort acceptance criteria in energy modeling https://www.ashrae.org/File%20Library/Conferences/Specialty%20Conferences/2018%20Building%20Performance%20Analysis%20Conference%20and%20SimBuild/Papers/C036.pdf
- How Humidity Affects Comfort https://www.contractingbusiness.com/service/article/20871274/how-humidity-affects-comfort
