Whole House Dehumidification

Written on: August 9, 2021 by J. Paige Freeland

With a steamy summer climate in much of the U.S., the annual maintenance check on your customer’s air conditioning unit is also an ideal time to discuss reducing relative humidity (RH) in their homes. As you may know, the air conditioner is not the ideal humidity- reducing solution. A whole house dehumidifier solution is best. In addition to offering increased comfort, the addition of a whole-house dehumidifier can also help reduce your client’s monthly energy bills. By reducing a home’s indoor moisture while outdoor temperatures are high, occupants will feel cooler and turn the air conditioner down.

Warmer summer air is able to hold more moisture, which is indicated by dew point. Dew point is the atmospheric temperature below which water droplets begin to condense. It varies according to pressure and humidity. The relative humidity is the amount of water vapor present in the air, expressed as a ratio compared to saturation at the same temperature.
High summer temperatures combined with a higher dew point reduce the atmosphere’s ability to evaporate perspiration from the skin (necessary for cooling the body), correlating to a higher level of discomfort for your clients.
Although a home’s air conditioning system removes moisture while reducing the temperature, the system stops when the desired temperature is met. Humidity remains high in the cooled space and your client’s discomfort level remains relatively unchanged. If one were to run the air conditioning unit until desired humidity levels were reached, it would probably feel like they were living in an igloo instead of a home. Only a system such as a whole house dehumidifier dedicated to moisture removal can solve humidity problems.
Any region experiencing a summer dew point average above 55°F could benefit by a whole house dehumidification system at some point. For example, the average RH in Florida during summer months is 89. We normally think of Florida as more humid than most States, but even in Michigan the average RH during the summer is 88. Connecticut sees an average RH of 86.
Finding the Right RH
For ideal health and comfort, the indoor relative humidity range should be somewhere between 40%–60%. Outside of that range (above or below), conditions can be adversely affected.
Leading literature on allergens recommends keeping RH to less than 51% to deter dust mites, since they can thrive at temperatures between 59°–95°F and an RH level between 55%–85%.
The Ideal Combination
From a human comfort perspective, the worst combination is a dew point above 65°F combined with a high RH of 70% or more. The most comfortable combination is reported to be a dew point of around 60 and an RH of between 40%–60%.
Some Other Reasons
Clearly summer season humidity is not the only reason to install a whole house dehumidifier. Folks living in humid places like Miami, New Orleans, Houston, Portland, Myrtle Beach or Charleston may feel humidity year-round and find great relief by installing a whole house unit. Otherwise, clothes and bedding might feel moist and sticky. Allergy and asthma triggers may intensify because mold and mildew growth may accelerate. The insect population may increase due to excess moisture that attracts moisture-loving spiders, ants and other pests. Low humidity can also extend the life of bug sprays!
Installing a dehumidifier can reduce musty smells, inhibit mold and mildew growth, prevent corrosion of metal and prevent wood from warping. A dehumidifier can also control excess moisture in a crawl space.
Why Whole House?
Room units generally treat only the space in which they are located, often require emptying, cleaning and other maintenance that whole house models do not. In addition, they take up valuable living space, are not always attractive and can be noisy. Even if they are in the basement, home owners may not wish to run up and down stairs to empty water bins.
Whole house units treat the whole house and often work faster to reach the desired comfort level in the home. With either choice, offering options that work to a homeowner means long-term satisfaction.
As a contractor, you have two goals: assisting a homeowner with their indoor air quality (IAQ) needs and generating income. Installing IAQ products can increase your income, not only through the installation, but also through ongoing maintenance. Offering IAQ products while servicing an air conditioner or furnace is the right thing to do for both your company and your customers. ICM