Many older homes simply used an air cavity as a method of insulation — an empty air gap is the only thing that stands between your exterior walls and your interior walls. While an air gap slows down thermal exchange, it still allows a large amount of cold outside air to infiltrate into your home. Some of the heated air inside your home will also escape outside. This air exchange causes the inside of your home to rapidly cool down, forcing your heater to work harder and increasing your energy bills.

If your exterior walls are poorly insulated, you're paying more money than is necessary in order to heat your home. How can you fix the problem? One of the best ways is to have your wall cavities filled with spray foam insulation in order to stop air from circulating inside it. Here's what you need to know about the process.

How Can You Tell if Your Exterior Walls Are Poorly Insulated?

You can check for poor insulation by feeling for a draft near a fixture that's connected to the exterior wall cavity, such as an electrical outlet or a light switch. Place a smoke pencil near the fixture and see if any air is coming out of it or blowing into it — a draft means that there's a significant amount of air circulating through your exterior wall cavity, which will raise your heating and cooling bills.

If you have poor insulation in the exterior wall cavity, you may also find that your walls are very cold during the winter even when your heater is running. That's another sign that outside air is blowing into your home and circulating through your exterior wall cavity, since it will rapidly cool down your interior walls.

Why Is Spray Foam a Good Choice For Insulating Existing Walls?

Spray foam insulation rapidly expands when it's sprayed into the exterior wall cavity, which allows contractors to easily fill the entire cavity with insulating foam — this makes it the perfect choice for insulating existing walls.

Cellulose insulation is another common choice for insulating existing walls, because it can be blown into the wall cavity in order to fill it. Cellulose insulation is made of small scraps of recycled paper or denim, and it works well as an insulator. Unfortunately, it tends to settle over time and leave gaps in your wall cavity that aren't insulated. Additionally, cellulose insulation tends to be more expensive than spray foam insulation.

Fiberglass insulation is often unfeasible to use as a method of insulating existing walls because it requires contractors to have full access to the wall cavity. You'll need to remove siding and drywall in order to provide access, which raises installation costs significantly.

How Is Spray Foam Installed in Your Existing Walls?

Installing spray foam insulation in your exterior wall cavity will block the circulation of air. You'll see a reduction in your heating bills because warm air won't continually escape to the outside, which forces your heater to work harder in order to maintain a warm temperature inside your home.

Using spray foam insulation in an exterior wall cavity is an easy job for an experienced installer. It's typically installed by going through your exterior siding in order to fill the wall cavity with foam. If you have vinyl or aluminum siding, sections of siding will be temporarily removed in order to provide access to the wall cavity. If you have wood, brick or concrete exterior walls, holes will be drilled in them in order to provide access. Siding sections will be replaced and holes will be filled in order to restore your exterior walls to their original condition after the spray foam insulation has been installed inside your wall cavity.

Contractors can also install spray foam insulation in your exterior wall cavity by cutting through the drywall on the inside of your home. This is often done when accessing the wall cavity through the outside is difficult or impossible, such as when you need to install spray foam insulation on a second-story addition.

Overall, the process of completely insulating a home's exterior walls with spray foam insulation can be done quickly and inexpensively by an experienced contractor. If you're tired of your home's high heating bills, call a professional spray foam contractor and schedule an appointment — you'll be able to stop air from circulating in the exterior wall cavity and keep your home warm and comfortable during the colder months.