Over the years, I have become accustomed to the fact that our electric bill varies in cycles. For a few months in the spring and fall, we have extremely low bills. That is countered by months of summer and winter with exceptionally high energy bills. It’s those summer months that I dread. Now, don’t get me wrong, I love summer. It is my favorite season. I love the fresh-cut grass, the smell of the rain from an afternoon thundershower, and being able to spend days at the lake or a quick trip to the beach. But I do not like the summer’s electric bill from my AC unit running seemingly non-stop.
I have always assumed that because we are in the south, the AC cycling all the time is expected. Then I learned it doesn’t have to be that way. Let’s go back to the beginning, all appliances radiate heat, so using a window air conditioning unit (that is vented to the outside) or a central air unit (where the compressor is outside) is really the only way to create cold air inside the house.
These units force the cooler air throughout, and if the home is adequately sealed and insulated, the circulating air keeps the temperature reasonably constant. So why do we get certain rooms that get hot? Or the temperature doesn’t stay cool throughout the day?
Two of the most important things to understand about insulation are conduction -heat transfer and convection-airflow.
Conduction is heat transfer through touch. A good way to picture it is this: When the sun shines on your house, the exterior heats up, and as it holds that heat, it transfers that heat to what is under it, typically a sheathing of some sort. As that gets hot and over time retains that heat, it is transferred to the studs. Then to the drywall and to the inside of the house. If you’ve ever had your AC go out, you will understand just how quickly that heat transfer can happen.
Convection is the heat transferred through airflow. The hot air outside is moving, and even if it’s just a light breeze, that movement against the house can find a way through even the most minor gaps. Once it gets inside spaces like the stud cavities, air can move with ease through traditional insulation like loose cellulose or fiberglass. That hot air then makes its way inside through electrical outlets and any other opening it can find. If you don’t have a good air seal, there is no barrier to keep out that hot air.
Although traditional insulations are good at keeping conduction to a minimum, they don’t do as good a job with convection. Luckily some insulations are excellent at both. Injection foam in your existing walls and spray foam insulation in the crawls space rim joist and attic can completely fill the spaces where they are installed. This will stop any air leakage and movement and create that air seal mentioned before and slow the rate of conduction to a crawl.
Think of your house like a cooler. Without naming names, the coolers that we used years ago worked ok. You put a bag of ice in, and that ice would melt at a relatively slow rate. Slow enough to keep the drinks cold while you played for the day. But, by the end of the day, you had very little ice left and a whole lot of water to empty before you put the cooler back in the car to go home.
On the other hand, the newer coolers of today are a whole different breed. (Much like the mythical snow monsters they’re named after.) You can put a bag of ice in and, because of the insulation in the cooler walls, three days later, you still have most of that ice. I think we’d all rather have a cooler that holds its temperature for days versus hours. And the same with our homes.
With an efficient air barrier in your home, your air conditioner won’t constantly be running as it tries to keep the temperature constant. This saves you money on your energy bills every month and on the maintenance costs for your AC units.
According to DTE Energy, homeowners can save around 10% on their total energy bills by sealing air leaks before adding insulation. After adding foam insulation, a homeowner could save up to 50 percent on their monthly energy bills.
We would love to answer any questions about the benefits of spray foam and injection foam. Or, to find more information about making your home more comfortable year-round, look to our learning center, send us a message, or call us to speak to a project manager.