Homes built within the last five to ten years are built to stringent requirements that require builders to meet certain standards. Part of the standards determine energy efficiency. For instance, how much insulation is in the walls and attic, the SEER (Seasonal Energy Efficiency Rating) rating of the air conditioning unit. These homes are built so tight that they are literally air tight. So what about those older homes?
Your typical home built in the 60’s, 70’s and 80’s are not so tight. They were built leaky. Unconditioned air in and conditioned air out. But this uncontrolled leakage can wreak havoc on your energy bills. What people are doing now to cut down on energy expenses is having their homes air sealed. A company that specializes in this field can come out and seal all your cracks and crevices (for a nominal fee of course).
The purpose of air sealing is to eliminate the uncontrolled draft from unconditioned air leaking in and conditioned air leaking out. This can also cut back on the amount of moisture that enters the home from uncontrolled air leakage.
What gets sealed? In the attic the joints where the ceiling sheet rock and the top plate (the piece of wood that creates the top of a wall) meet. Joints around windows and the spaces between the walls of your light switches and plugs are some of the areas that get sealed. Once finished you have one nice air tight home with little to no air infiltration from the outside. Great! Right?
Air sealing can have a negative effect on your home too. You have exhaust fans in your bath room that push inside air out. The range vent hood gets rid of the nasty smoke from your burned casserole, and the dryer vents that warm damp air outside as well. With all these vents running, where is the makeup air (The air needed to replace the air removed) going to come from? What goes out must come in. Well, it comes from outside but if the home is airtight it cannot pull fresh air in. If you have combustion appliances like a gas furnace or water heater, an airtight home can cause these appliances to work improperly and inefficiently. This can all be combatted by installing an exterior vent to your central A/C that allows exterior air to be pulled in when needed i.e. when that bathroom exhaust fan is running on full blast.
So, why are you adding ventilation for outside air to come in when you just sealed your home to prevent exactly that? This ventilation allows controlled air infiltration. Outside air comes in when the home has negative pressure inside caused by running an exhaust fan or a gas fired appliance. Without controlled ventilation, during cold or windy weather, too much air may enter the house. When it's warmer and less windy, not enough air may enter, which can result in poor indoor air quality. With that, air sealing is a beneficial way to help control the amount of air that moves in and out of a home thus reducing your heating and cooling load. And that will help reduce your energy bills. Depending on the methods used for air sealing the home, the occupant can see a return on their investment in one year or less.
Thank you for taking the time to read my blog. If you like what you have read stay tuned for more to come. When you need a Home Inspection please give me a call to schedule one. I am a licensed Professional Home Inspector serving Dallas, Texas and surrounding cities. I provide home inspections for Buyers, Sellers,Warranty and Maintenance Inspections.