Energy Efficiency

Published on April 8th, 2017 | by Scott Cooney

Insulating older windows without replacing them: cost effective Window Inserts product review

Older windows can be a huge waste of money when you try to heat or cool your home and window inserts can make a big difference.

R values (a measure of insulation, measured in “resistance” of heat passing from one place to another) are very, very low for older windows. Whereas your walls might have an R value of 20-40, depending on local zoning codes, how well built your home was, and how much insulation was added, your windows might have an insulation value of 1 or 2. What that means is that while you’re trying to keep your home cool (or warm in the winter), you’re continually losing your desired temperature more through your windows than just about anywhere else in your home (unless you’ve got a gaping hole somewhere).

Replacing windows can be exceptionally expensive. I had 4 single pane windows in my home that were clearly losing a ton of heat (you can tell just by touching them…if they’re really cold in the winter to the touch, that means that they’re sucking heat out of your home). One company’s bid to replace just the four windows with something more energy efficient came to well over $6,000 for parts and labor. So what’s a frugal greenie to do?

Window Inserts: A Product Review

Window inserts are great products to help you cut your utility bills and improve the comfort of your home. Recently, I got a couple of window inserts through WindowInserts.com, and put them over a couple of the draftiest windows in my house. The difference was immediately noticeable. The inserts, which are an aluminum frame with weatherstripping foam around the outside, and a clear vinyl “window” in the frame, just press directly into the frame of your window, trapping an extra layer of air between your window and the insert, thereby creating a thermal barrier. The net effect is to help keep the temperature outside from becoming the temperature inside.

Now, I’m an eco-nerd, and just happen to have a thermal imaging camera. So I took some before and after photos of the windows. Check out the below–basic idea is that, with a thermal image, you can see where heat is being lost. The photos on the left show the windows I have in my house without the insert, and the photos on the right show the result after the window inserts are, well, inserted.

Window Inserts

Window Inserts

If you’re scratching your head and saying that the images on the right look basically like one big sheet of orange, well, you’re right–that means that heat’s no longer being lost, and you’re seeing one thermal temperature across wall, window frame, and window. Wicked cool, right?

But how do they look aesthetically? See for yourself. Check out more before and after photos:

Window Inserts Window Inserts





Tags: , , ,


About the Author

Scott Cooney (twitter: scottcooney) is an adjunct professor of Sustainability in the MBA program at the University of Hawai’i, green business startup coach, author of Build a Green Small Business: Profitable Ways to Become an Ecopreneur (McGraw-Hill), and developer of the sustainability board game GBO Hawai’i. Scott has started, grown and sold two mission-driven businesses, failed miserably at a third, and is currently in his fourth. Scott’s current company has three divisions: a sustainability blog network that includes the world’s biggest clean energy website and reached over 5 million readers in December 2013 alone; Pono Home, a turnkey and franchiseable green home consulting service that won entrance into the clean tech incubator known as Energy Excelerator; and Cost of Solar, a solar lead generation service to connect interested homeowners and solar contractors. In his spare time, Scott surfs, plays ultimate frisbee and enjoys a good, long bike ride.

Find Scott on



Leave a Reply

Your email address will not be published. Required fields are marked *

Back to Top ↑