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How to Measure and Install Storm Windows

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How to Measure and Install Storm Windows

In cold weather, one-third of the heat lost in your home seeps out through gaps in doors and windows. Storm windows create a tight seal, which blocks heat loss. This lowers your utility bills and helps make you more comfortable in the winter. To ensure a tight fit, you need to measure properly for storm windows and install them correctly.

Storm Window Types

Storm windows fall into two general types: exterior and interior.

Exterior storm windows go over your existing home windows. They can alter your home’s curbside appeal, but do not affect your home’s interior. With exterior storm windows in place, you can still open and close the windows at will.

Interior storm windows go on the inside of the windowsill. This makes them invisible from the home exterior but highly visible from inside. With interior storm windows in place, you cannot open or close the windows.

Exterior Storm Window Measurement and Installation Tips

Standing outside the home, measure the width of the window casing from one inside edge to the other inside edge. Take measurements at the top, bottom, and center of the window since window casings may not be square.
Next, measure the height of the window from the top and bottom edge of the window casing. Round your measurements down to the closest 1/8-inch to ensure a tight fit.

To install the exterior storm window, you will need a screwdriver, putty knife, caulking gun, and caulk. As a first step, caulk the top and both sides of the window sill. The caulk helps to ensure a tight fit.

Push the exterior storm window into place against the window casing. Press to get a snug fit. Use your screwdriver to screw the storm window to the top corners of the window frame.

Press down on the expander at the bottom of the storm window using your putty knife. Continue pressing until the expander meets the bottom of the window sill, which is often angled down.

Check the position of the window before installing the two screws on the bottom. Ideally, there should be no more than 1/16 of an inch gap on the top, bottom, and sides of the storm window. If everything looks good, screw the bottom of the storm window to the window frame to complete installation.

Installing Storm Windows

Interior Storm Window Measurement and Installation Tips



Use a measuring tape to measure both the height and the width of the window frame, from inside molding to inside molding. Take two to three sets of measurements, since your window frame may not be exactly square. Round your measurements down to the nearest 1/8-inch for the best fit. Your storm window will fit into this space between the interior molding.

Interior storm windows usually install on a track, using clips, or using magnets. If your interior storm windows install with clips or magnets, you can push the storm window into the window frame opening. Press firmly to get a snug fit. Then use the clips or magnets to attach the window to the window frame.

To install the track style windows, you may first need to remove window screens from the window track. Hold the storm window next to the track, and then angle the storm window to get the top edge into the bottom of the track. Push up to move the storm window along the track. Once the window is fully positioned in the track, depress the tabs at the bottom of the storm window to lock it into place.

You can remove both types of storm windows when winter passes to enjoy a fresh breeze. Storm windows are much cheaper than replacement windows and offer energy-conservation and cost-saving benefits for homeowners.

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2 thoughts on “How to Measure and Install Storm Windows”

  1. Thank you for your information on different storm window types. It is interesting that you said interior storm windows make it so you can’t open or close your windows. My aunt and uncle recently moved to an area where they get a lot of bad storms. They will be interested to know more about how they can protect their windows.

  2. I had no idea that storm windows could help lower your utility bill and block heat loss. My wife and I live in an area that has hurricanes almost every year and we need to install storm windows before the next one hits. I’m glad to know that there are other benefits as well.


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