When it comes to insulating your home, you can have too much of a good thing. A tight house often lacks proper ventilation, which is necessary in order to keep mold, mildew, volatile organic compounds (VOCs) and other contaminants from building up. Ventilation also helps prevent moisture build-up that can cause structural damage.
Good air flow is important for a healthy home. So, the general rule of thumb for insulating is that you should do what you can to seal up your home, then mechanically ventilate your indoor air. This creates cleaner, healthier air inside your home, reduces air leaks and keeps moisture from rotting your wood and damaging insulation. Some air leakage is likely in any home, especially older ones. However, if you have good ventilation that removes indoor air pollution and brings fresh outside air in, you should see an improvement in your home comfort as well as the quality of the air you breathe.
Whatever the status of air leakage in your home, mechanical ventilation systems can play a significant role in promoting air flow and reducing odor and moisture in your home. One way to achieve better ventilation is to install fans that remove moist air. Every home should have both kitchen and bathroom fans to effectively remove moisture and odors. In fact, the American Society of Heating, Refrigeration and Air Conditioning Engineering (ASHRAE) recommends that kitchens have an intermittent exhaust capacity of 100 cfm (cubic feet per minute), and bathrooms 50 cfm.
ASHRAE also recommends a minimum ventilation rate of 15 cfm per person (or .35 air changes per hour), whichever is greater. That means introducing fresh or filtered air equal to just under one‐third of the total volume of air in your home every 60 minutes or more than 8 complete air exchanges per day. To put this rate of exchange into perspective, an older home without insulation or weather‐stripping might have as many as 8 air exchanges per hour. During the heating or cooling season, that adds up to a lot of energy consumption, and a lot of wasted energy dollars.
So, if your home is showing signs of ventilation problems such as high energy bills, moisture build up, condensation on the windows, mold, mildew and other unpleasant effects of poor air quality, have us come out to assess the situation. This is also a good time to talk about how to improve air quality through various mechanical means, such as dehumidifiers and air cleaners that work with your air conditioning to provide clean, cool and dry air year round.
Overinsulating has become an issue, especially with newer homes that are built to more energy-efficient standards. Mechanical ventilation helps keep your indoor air healthy and prevents costly repairs to your home down the line. Ask us about your options for sealing and ventilating your home to achieve better comfort.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about proper ventilationand other HVAC topics, click here to download our free Home Comfort Resource guide.