The performance of storm windows vs regular windows can depend on what windows you have to start out with. In this blog we’ll cover typical replacement windows and storm windows, what insulation you can expect from each and what noise abatement performance to expect out of each category.

Storm Windows

Storm windows are a second window pane added to the outside or inside of your already existing window. Exterior storm windows attach to the outside of your window frame and interior storm windows to the inside of your window frame.

Replacement Windows

Replacement windows replace your already existing windows – either by installing a new type of window style or technology, or because the seal on the old window has failed.

close up of one of indow window insert options

Replacement Window Options

The most popular replacement windows are double hung and casement, wood frame, vinyl frame, or fiberglass frame. Casement style windows are more airtight than double hung, so they will provide more insulation and defense against drafts than double hung. Double or triple glazing adds an extra pane of glass with air or gas between them. This provides better insulation and sound reduction (especially triple glazing), but can be very expensive. Low-E coating reflects heat to improve efficiency. Read the consumer report on replacement windows.


“Star-qualified windows can lower your energy bill by an average of 12 percent. That’s only $27 to $111 a year for a 2,000-square-foot single-story home with storm windows or double-pane windows, $126 to $465 if your home has just single-pane windows, according to Energy Star.” claims the replacement window consumer report. Interior storm windows can save an average of 20% on energy bills according to the third party studies.

indow storm windows vs regular windows

Storm Window Options

Adding an interior storm window to a double-pane window can reduce outside noise up to 50% (10-12 dBA). Adding an interior storm window to a single-pane window can reduce noise up to 70% (18.9 dBA). Replacement windows reduce outside noise up to 20%. This data is based on third party studies performed with Indow window inserts. Because the insert is made of acrylic, it blocks sound better than standard window glass. A near airtight seal is created between the insert and the glass, which also helps Indow window inserts reduce outside noise.

Old windows receiving storm windows might need some restoration before this type of performance can be expected. Meanwhile, replacement windows will bring the performance described as soon as they are installed. Storm windows can provide different needs—acoustic or UV protection—in just one room or window that fits that space’s needs.

Analyze your space to determine your needs. Is noise an issue for your? Then storm windows are probably the way to go. You can read our full comparison of storm windows vs replacement windows to get a better idea.

person walking by restored window

How to Get Storm Windows

All inserts are backed by a Snug Fit Guarantee because of our laser measurement system. Here’s how we do it:

We send you a laser measure kit with a fun laser measure tool (pew pew). It works just like a flashlight—with the press of a button, you get the dimensions. Enter the measurements displayed on the tool into our online portal. It checks for accuracy.

Our fit experts check the measurements for accuracy (again). If everything looks good, dimensions are on their way to becoming your custom insert. It’s that easy.

We developed the tool and software (with error detecting algorithm) because it’s the best way we know how to seal windows for winter.