Help Me Improve Our Humid Home
During the hot summer months, many homes across America experience high humidity levels. Additionally, these homes often contain window air conditioners or central air conditioning. However, homeowners use them sparingly because they increase the monthly utility costs. Conversely, minimizing the use of air conditioning systems typically means an uncomfortable home. Fortunately, taking a closer look at the key contributing factors helps homeowners understand underlying comfort issues.
Understanding Relative Humidity
Homeowners must understand that the air that surrounds our home contains moisture. The moisture in the air is described as relative humidity. Furthermore, relative humidity measures the amount of moisture in the air compared to the total amount of moisture the air can hold at that temperature. For example, air that is 70 degrees and 40 percent relative humidity means the air has 40 percent of the total amount of moisture it can hold at that temperature. Air at 100% relative humidity is saturated and cannot hold any more moisture.
The concept of relative humidity becomes more difficult because warm air holds more moisture than cold air. For example, 80 degree air with 50 percent relative humidity contains much more moisture than 60 degree air with 50 percent relative humidity. Even though both air samples contain 50 percent relative humidity, the warmer, 80 degree air contains much more moisture.
When the outside air temperature increases, the very warm air contains high levels of moisture or humidity. In the summer, air becomes hot and humid. As a result, minimizing that air from entering your home helps keep your home less humid in the summer.
Understanding Air Exchange
Homes lose more air to the outside than most people realize. It is a continual, silent process that goes on every moment of every day all summer long. Air exchange makes matters worse. In air exchange, an equal amount of hot, humid air enters your home and replaces cool air.
Air exchange occurs where air leaks exists. Leakage locations include gaps, cracks and holes between your house and attic such as chimneys and plumbing vent stacks that rise from the house to the attic. Where wires and ductwork run from the attic to the house and where recessed canned lights, dropped soffits, kneewalls and attic hatches connect the house to the attic. Similar types of holes connect your house to the crawlspace (or basement) and are between your windows (and doors) and the exterior walls of your home.
Air leaks waste cooled air in your home as well. For example, air leaks in ductwork lose the cool air in your duct system to attics, crawl spaces or directly to the outside before it ever has a chance to cool your home. More importantly, however, leaks in return ductwork located in attics or crawl spaces draw large amounts of very humid air into your return duct system and then into your home.
On the positive side, once homeowners determine the underlying reasons for uncomfortable conditions, a solution that greatly improves your home comfort exists. Plus, these solutions help save energy and money as well!