Spray Foam vs Fiberglass Insulation Around Windows

Best Insulation for Windows?

Spray, don’t stuff: Fiberglass insulation does not provide an air seal. On the other hand, low-expansion spray foam does.

There are a couple of things you need to keep in mind when insulating around your windows – the ease of installation and stopping those drafts.
Let’s take a look at window insulation foam and fiberglass, how they are installed, and how they work.

Fiberglass Window Insulation

Fiberglass insulation is made of plastic reinforced by tiny glass fibers, which gives the plastic additional strength while improving its insulation capacity.
For small projects, like windows, you can get small rolls of the material.

While fiberglass is inexpensive and can be a do-it-yourself project, you have to be really careful when handling the material. The small glass particles can lodge in the skin, be inhaled causing respiratory problems, and can trap allergens from outdoors.

Fiberglass also still allows for air movement through it and won’t create an air barrier, according to Fine Home Building.

To install the fiberglass around your windows, you will need to remove the frame around the window. The fiberglass will need to be cut so it fits snuggly in these spaces without wadding it up. It might seem easier just to cram the fiberglass in this small cavity, but this can actually lead to pockets of air that will allow for a bunch of air leakage. If the fiberglass isn’t installed properly, it will not work as well insulating around your windows.

Window Insulation Foam

Window insulation foam is a low-expanding, low-pressure polyurethane spray foam that is designed to create a weather-tight seal around windows and doors when installed properly.
It can be purchased from any home improvement store and comes in a can.
The canned foam is great to create the air seal you are looking for around your window, but you need to install it correctly.
The installation process is similar to fiberglass – you can remove the frame around the window or the entire window.
Because canned foam has a low-expansion rate and is low-pressure, you will want to ensure you are filling the entire cavity around the window, so you don’t have any leaks. This could take a couple of passes with the can hose.

The Best Window Insulation

Neither material is terribly expensive and can be done as a DIY project, so it comes down to what you decide is the best fit for your home.
Fiberglass will still allow for air movement through it, leaving you with the same drafts and issues you were having before adding the new insulation.
If you want to stop those leaks around your windows completely, you’ll need a material that creates an air seal.
That material is spray foam insulation.
If you want to learn more about the benefits of foam insulation for the rest of your home, check out the Learning Center on our website.

Spray Foam Insulation Contractors in NYC

Spray Foam Insulation NYC is a spray foam insulation company based in New York City, NY specializing in all applications of polyurethane spray foam. We are proud to service New York Metropolitan Area, Manhattan, Brooklyn, Queens, Staten Island, The Bronx, Long Island and New Jersey.

For more information or to speak with one of our estimators, Call us today at (718) 594-1976