How to Save Money on Your Heating and Cooling Bills...
Zip Up Your Thermal Envelope to Save Energy
For most of my childhood my bedroom did not have heat or air conditioning. The house was a two-story farmhouse that had a propane stove and a window air conditioner in the kitchen. I guess the idea was that the air would make its way to the other rooms. Unfortunately the only way it could make it upstairs to my bedroom was if the door at the bottom of the stairs got left open, which didn't happen very often.
I have a strong suspicion that the house was lacking in proper insulation. But watching the curtains flutter during a good breeze outside seemed to be an indicator of something much worse... air invasion.
One of the biggest culprits to having high energy bills is having an uninsulated, unsealed building envelope. There are many ways to lower home energy bills, but first you have to identify and stop air infiltration.
A home’s “thermal envelope” separates you from outside elements. It’s like wearing a nice coat when it’s cold: If you zip up your coat, you’re snug and warm, but if it hangs open, you’re left freezing. By properly sealing the building envelope and creating air barriers, and then installing insulation, you keep hot air out in summer and cold air out in winter.
Sealing your home’s thermal envelope involves applying caulk and foam to cracks and gaps and correctly installing insulation. If the insulation isn’t put in well, it’s not doing its job. Typically, incorrectly placed insulation leaves gaps between walls and doors or windows, or where the ceiling meets the walls.
If there’s a gap in insulation, heat gets through. These gaps can range from the thickness of a sheet of paper to much larger holes, like where your cable or telephone wires enter the house.
Understanding that you have air infiltration is only half the battle. You have to find and stop the invaders.
The first step requires putting a 'tight lid' on a house because heated air rises and will work its way out of the living space.
If your local public power district or electric cooperative offers home energy audits, take advantage of them.
A blower door test will show you how much air flows in and out of the house each hour. And while the home is depressurized, you or your energy advisor can walk through the house with a special smoke pencil to see where you’re having air flow. A thermal imaging camera is even more dependable for locating air flow.
The bottom line: If air is getting through, your energy bills will go up and you won’t be comfortable.