WARNING – THE FOLLOWING GIVES INSTRUCTION ON HOW TO WORK ON PART OF THE ELECTRICAL SYSTEM IN A HOME. IT IS TECHNICAL IN NATURE AND NOT MEANT FOR EVERYONE. IF YOU DO NOT FEEL COMFORTABLE TAKING YOUR LIFE INTO YOUR OWN HANDS, OR POSSIBLY DAMAGING YOUR HOME, READ ON, AND THEN CALL A PRO.
I’ll let you in on a little secret. Insulating your home is only half the battle when it comes to saving money on your energy bills. The other half, and some would argue the most important, is that you must air seal the outer walls/ceiling. This is also known as the building envelope. We must stop air movement from the living space and the outdoors too.
The Science Of Building Heating and Cooling
In physics, the second law of thermodynamics says that heat flows naturally from an object at a higher temperature to an object at a lower temperature; and heat doesn’t flow in the opposite direction of its own accord. This means hot moves to cold on its own. In the winter, your hot air air is trying to escape the house, and in the summer, the hot air outside is trying to get in. It’s a never ending battle. Every little crack and hole in your house is a path to losing money, comfort, and is making your furnace/air conditioning work harder.
Take a Peek
Behold the beautiful wonder of thermal imaging! I love my thermal camera. It has made me a hero more times than I can count during my home inspections. Thermal Imaging Inspections take inspecting to a whole new level. You can see in the image below, an electrical outlet in my house. I’ve marked the hi and low temps to make it easier for you to understand the colors. The blue area is all the cold air leaking in around the edge of the electrical box, and the holes where the wires come into the box.
Stopping these leaks is a small piece of a larger puzzle, but still a piece nonetheless. The first thing you do is kill the power to whatever you are working on. Don’t try any of this on a live circuit or you could electrocute and kill yourself. Don’t be stupid. Now that you’ve turned off the power you’ll want to remove the receptacle itself. GENTLY pull it straight back and out of the box. If the person who wired your house left the wires too short in the box to safely pull the receptacle up and out of the way, stop now. You could pull the wires off the receptacle, break a wire, etc… Call in a pro to have your wires extended. If you can pull out your receptacle and it looks like the image below, carry on.
Seal It Up
Now that we can work without fear of breaking wires and/or electrical shock, I use caulk and expanding foam to seal the box. Using a high quality painters caulk, caulk the edge of the electrical box to the drywall itself. I got lucky and the drywallers did a decent job of cutting out for my boxes, so the gap is not very large. Your mileage will vary on how much caulk it takes to seal this up.
Now that the box-to-drywall connection is sealed, let’s focus on the wire penetrations. You may have one, two, or even three sets of wires coming into the box itself. This number will vary on how outlets/switches are in your box. Treat them all the same here. I have two sets of wires coming in to deal with. A small shot of spray foam around each wire is all it takes. You can see here how the foam will spread itself around the wires and seal them up.
Expanding foam in the disposable cans can get pricey. Once you crack the seal on them the clock starts before it becomes useless. Remember, a little goes a long way with expanding foam. This stuff will grow and grow once you squirt it out. If you get trigger happy and get too much in the box; just let it cure and dig it out. Don’t try to touch it wet. You’ll just end up with a sticky mess on your hands. One can will likely do your whole house. So if you have to buy these types of cans, you may want to tackle the whole house at once to save on foam.
Here is another thermal image pic showing the improvement we made. This area is a full 6.1 degrees warmer. But more importantly, we have stopped the airflow from getting into the living space of the house. That airflow cost money and comfort 24-7-365.
But Ben, why is the area still blue and cold you ask?
Understand that what we are working on is air sealing of this box , not the insulation around it. We are still seeing cold temps and blue coloring because the insulation around this particular box is non-existent. This receptacle is above my fireplace where most builders do not attempt to insulate. I”ll tackle the insulation another time.
This procedure is good for just about every penetration in your home’s envelope. All your receptacles, light switches, hard wired smoke detectors, ceiling lights, ceiling fans, and any other hole you may have. It’s a quick process. Takes me about 2 minutes per box to seal it up, and you reap the benefits instantly.