Reduce Heat Loss With Thermal Panel Window Insulation

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A completed, airtight corner.
A completed, airtight corner.
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The pop-in shutter is one variety of thermal panel window insulation. After assembling a wooden frame to fit your window, lay it on a sheet of insulation so you can mark and cut out the beadboard. Do this again with another piece of insulation so that the shutter will be two layers thick.
The pop-in shutter is one variety of thermal panel window insulation. After assembling a wooden frame to fit your window, lay it on a sheet of insulation so you can mark and cut out the beadboard. Do this again with another piece of insulation so that the shutter will be two layers thick.
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Once you've thoroughly glued the two sections of beadboard together, run some additional adhesive along the inside of the frame.
Once you've thoroughly glued the two sections of beadboard together, run some additional adhesive along the inside of the frame.
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A completed panel will help keep Old Man Winter from knocking on your glass doors!
A completed panel will help keep Old Man Winter from knocking on your glass doors!
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The beadboard panel is another variety of thermal panel window insulation. This large, unframed heat holder is held in place by salvaged magnetic strips that have been glued into channels along the insulation.
The beadboard panel is another variety of thermal panel window insulation. This large, unframed heat holder is held in place by salvaged magnetic strips that have been glued into channels along the insulation.
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The final product is easy to install . . . attractive . . . and very inexpensive!
The final product is easy to install . . . attractive . . . and very inexpensive!

You may recall that in The Homemade Thermal Shade we presented three varieties of fabric thermal shades, all of which rang in at about $10 a window. (In case you missed that heat-saving advisory, we should tell you that the price is very modest: Commercial window insulators can cost $90 or more!) Well, in this installment, we’re going to present two other methods of thermal panel window insulation that are particularly good for covering large expanses of glazing. And in keeping with our previous models, these heat-holding panels can be made for little more than $10 a window.

Our shutters are primarily composed of expanded polystyrene insulation, a foamlike material that comes in 4′ X 8′ sheets and is often used in the building trades. “Beadboard”, as it’s known, is rigid yet light in weight and easy to work with. It makes a durable, inexpensive, and simple-to-install thermal shutter. Polystyrene is rated at R-4 to R-5 per inch (so in the case of the 1 1/2″-thick pop-in shutters detailed below, the insulative value would be about R-7).

The MOTHER EARTH NEWS thermal panels are pretty much of the “generic” variety, but you can fancy up these no-frills shutters with paint, fabric, or wallpaper if you like. The foam panels may be left in the windows to forestall heat loss both day and night . . . or you can remove the cover-ups (which obviously do block out light) to let in the sun’s rays during the day. If you decide to keep the shutters in the windows for long periods of time, you should check occasionally for mold or mildew caused by condensation of moisture. Wiping off window surfaces with a dry cloth and dabbing diluted chlorine bleach on the sills can help prevent such problems.

Pop-in Shutters 

Our first thermal project this go-around was designed for a 3′ by 7′ expanse of glass that included one 32″ X 36″ unit and two 23″ X 36″ windows. To cloak these panes, we decided to make three pop-in shutters . . . beadboard blocks lodged in a wooden frame and wedged in the window. The sills and casings we worked with had adequate depth to accommodate our shades, but you could insert the panels in a window without a casing–such as those found in a mobile home or on a brick or stone-veneered wall–if you mounted an exterior frame around the window first.

  • Published on Jan 1, 1984
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