Insulating Your Windows

It’s almost winter and we’re already beginning to feel the cold settle in here in New England. Now is the perfect time to start Insulating your house before the real winter cold fronts start to hit us! In this four part series we will take a look at the most common places you suffer heat loss in your home. This blog will take a look at the best ways to insulate your windows for this upcoming winter after you get a very needed window replacement with a brand new window installation and after you’re done you can decorate them with some blinds or even some shutters. If the reason you are going to get a window replacement is to keep the heat in your home, then consider getting some Firetube Boilers so your home is never cold. 

Blog Series: Insulating your home
Part 1: Windows
Difficulty: Easy
Time: 1-3 hours

Windows are one of the most immediate offenders when it comes to heat loss in a home or cooling if you have an air conditioning unit. If you still feel that your home is still losing it’s cooling after insulting your windows then you may need an ac repair.

Step 1: Inspect the Windows

Cracked Window Pane Koopman

This should be the easiest part after you get your window installation. Take a good look at each window individually. Is the wood significantly chipped or rotted away? If it is it’s probably time to replace the frame. Likewise take a close look at every pane of glass. Small chips or cracks can be filled in with a clear putty for a quick fix but you should ultimately get a proper window repair. Larger cracks should be replaced immediately before it gets too cold!

Step 2:  Consider new or replacement windows

Depending on the age and condition of your windows, and the quality of the previous window installation, you may want to consider replacing your windows – even in just a portion of your home.  Koopman Lumber has several dedicated professionals that focus exclusively on double glazed windows and doors and can walk you through the process to get the most efficient installation for your home.

Step 3: Caulking

Caulking Window Koopman

Next inspect the caulking around the inside and outside of the frame. If the caulking appears old and worn, or chipped off in any area it’s easiest to just strip away the old caulk and replace it with a new layer. Take a putty knife and scrape around the edge of the window to remove all the old caulk. Be careful not to chip away any paint while doing this! Prepare your tube of caulk in the caulk gun and cut away the top of the nozzle create a hole about a 1/4″ in diameter. Alternatively most caulk guns will have a small hole by the trigger that will cut the top of the nozzle away for you. Place the tip of the nozzle into the hole at an angle and pull the trigger to cut it away. At the end of your caulk gun there should be a poker that you can use to poke through the seal at the base of the nozzle. Poke several holes in it, wipe off your poker, and load the caulk into your gun. If your caulk gun doesn’t have a poker, you can use a long nail or bent coat hanger for this.

Squeezing gently apply the caulk at a slow but steady rate to the cracks along all four sides of the window, going over anywhere that might create an air leak.  Squeeze caulk into any voids.  After applying the caulk smooth it down with a plastic spoon or your wet finger. Wipe off any excess caulk from your hands and the caulk tube before it dries (you don’t want that stuff to dry on you!).

Step 4:  Expanding foam insulation for larger gaps

Koopman Great Stuff Expanding Foam Window Seal

Sometimes after installing a new window or for older more worn out windows you’ll need something thicker than a bead of caulk to seal a gap. For this we’re going to need expanding foam insulation. Make sure that you ONLY use the low expansion spray foam specifically labeled for “Windows and Doors.” You may need to pull off the trim for this part. Safely remove the trim and use the expanding insulating foam to seal any larger air leaks underneath. Allow it to dry and cut away any excess foam that has expanded beyond the mouth of the gap. Any blade will be able to cut through this foam. When you’re all set you can install the old trim if it’s in good condition. If the material is old and worn or you’re looking for a different aesthetic then this is a great time to replace the trim!

Step 5: Sealing Windows

There are several popular ways to properly seal off home windows and several really cool products out there to do this with.

Window Curtains Koopman

The most common types of insulation used for windows are cellular shades and heavy, layered curtains. Cellular shades still allow sunlight through their slits leaving you with a warmer, more well lit room. Layered curtains allow less sunlight through but are often the best looking, more elegant option. Depending on the material and how heavy the layers are it also lets in less draft and keeps in more warmth than cellular shades.

The first really cool product we’ll talk about is rubber sealing strips. These strips will come sized longer than your average window (or door if you buy the door kit) and will either have an adhesive strip or predrilled pin holes for adhesion. measure off the length of the top, sides, and bottom of your window and cut the stops down to the exact length. Place the side lengths of rubber against the side of your window almost flush against it and seal it with either the adhesive strips or the pins (or nails). The top and bottom pieces you will want to adhere as tight against the seal as possible.


The second really cool product is window insulation film. We recommend Frost King Window Insulation for this project. This is basically shrink wrap that you place over your window and then gently use a hairdryer to shrink over it. It’s easy to use and can be a lot more fun than other methods! (that’s a plus on our books!). Simply apply the double sided tape that comes with the kit to the window frame on all 4 sides. Hold the window film up to the window and cut it down until it is 1 inch longer on all sides than where the tape is placed. Now pull back the covering from the top strip of tape and, working from the middle outward, put up the plastic. Smooth it out with your hands as best you can, and then repeat on the other three sides. Now get out your hair drier and, on the low setting, work from the outside in. Hit each area until it is smooth and clear. Once you’re done it’s safe to cut away the excess plastic.Koopman window seal plastic wrap

There is also decorative insulation film that looks exactly how it sounds. Like the above insulation film it covers the glass panes of your window, adhering to them and insulation them. They come with patterns and decoration that add a bit more frill and a bit more fun to your windows than a boring, clear piece of plastic.

Wrap Up

Window sealing is a fast, cheap, and efficient way to save money this winter on your heating bill. Most people report saving over $100 during the course of just one winter! Stay tuned for our next edition for insulating your home, where we’ll talk about doors. Aside from windows, doors are the easiest things to insulate in your house and can save you even more money!

Thanks for tuning into this blog, if you have any questions about this or the products we sell, check us out online at Koopmanlumber.com or visit one of our many Koopman locations. Don’t forget to check out part two of this great series “Insulating Your Doors” by clicking here!

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