As winter approaches in the Northern hemisphere, one can feel the cold air near interior windows. How can I reduce the amount of heat lost through windows?

Essential criteria:

  • cost must be less than $100 for multiple windows
  • must not block all light
  • must be either removable and non-damaging or allow for opening of windows come spring

Related: Seal a window Temporarily (in monsoons)

  • 2
    Are you trying to eliminate the heat loss through the panes of glass itself? Or are you trying to eliminate air leaks around the glass and in the frame?
    – JGTaylor
    Commented Nov 17, 2015 at 20:53
  • I've sealed leaks around the window, so loss through the pane itself.
    – Minnow
    Commented Nov 17, 2015 at 21:31
  • Lots of good options here, thanks all. Will experiment and then accept the best result.
    – Minnow
    Commented Nov 18, 2015 at 3:16
  • 2
    Doesn't fit your budget, but perhaps an still worth considering: custom-made removable inserts. Commented Nov 18, 2015 at 17:35

8 Answers 8


Science to the rescue! 3M makes a type of insulating window film similar to saran wrap but thicker and designed to be applied with a hair dryer so it shrinks to be perfectly clear around your window frames.

At about $15 for 5 windows, it fits your cost parameters too.


The old standby for this was "temporary storm windows", for houses that lacked custom-fitted storm windows.

A storm window overlays the window frame on the outside to prevent exterior air (along with rain, snow, etc.) from directly contacting the single-pane sashes; it provides some insulation (less effective than modern multipane glass, but much better than nothing), as well as physical protection (storm windows were often shatterproof acrylic plastic).

Temporary storm windows are a simple clear plastic sheet (plastic drop cloth, plastic tarp, etc., as long as it's clear), held in place by a strip of lath on each edge, which is stapled or brad nailed to the window frame. The clear plastic provides an airflow seal, some trapped air insulation, and physical protection (less so than acrylic sheet, but still much better than nothing), and is very inexpensive: they used to sell kits in hardware stores, but you can buy clear plastic sheet, lath, and brads cheaply at the big box home improvement stored. These are disposable; removing them in the spring destroys at least the plastic. They're cheap enough, however, that that isn't a big deal compared to the heating fuel savings.

Long term, you're best off if you can afford to have the windows replaced with proper multipane glass -- but temporary storm windows are a good, cheap, short term solution that worked well for many years before the current solution was available.

  • 3
    A similar solution can also be done on the inside, and is then easier to fasten as it doesn't have to endure the power of weather on the outside...
    – holroy
    Commented Nov 17, 2015 at 22:03
  • Even having them outside will cause them to balloon up due to the windows probably not being air tight. Collection of moisture can decay the adhesive and cause the plastic to peel.
    – Nelson
    Commented Nov 18, 2015 at 9:53

Home-made pelmets

Heavy curtains are a good start if you can afford them, but if you already have curtains or blinds of any kind, adding pelmets will make a significant difference. Pelmets reduce convection currents, whereby air coming into contact with the window surface cools down, falls to the floor and pulls more warm air down past the top of the curtain, ad infinitum.

With such a tight budget, making your own pelmets is probably the best option. Google "home-made pelmets" for some instructions. (You could also try "box valance" instead of pelmet.)

Here are a couple of examples:




I've successfully used pieces of bubble wrap trimmed to fit the glass, with no gaps at the side. You can wet the smooth side of the bubble wrap with soap/detergent and water, and simply stick it to the glass.

Light transmission is a little reduced, but the view is obscured significantly.

The cost is probably $0, and you can layer this solution with curtains and other suggestions.

  • Unless they have very few or small windows, I doubt most people have enough bubble wrap lying around to make this a $0 project. I can't imagine it would be over the target $100, though, except for rare cases.
    – TIO Begs
    Commented Nov 18, 2015 at 14:17
  • 2
    @Geobits Fair call - bubble wrap is not hard to find though. My previous workplace threw away quantities regularly. Ask around, places like freecycle.org allow wanted requests to be posted.
    – Criggie
    Commented Nov 18, 2015 at 19:33

I've seen my grandmother put saran wrap on the windows of her old lakeside house in the winter. When I traveled in New Zealand where most of the houses seemed poorly insulated, I saw a lot of people put saran wrap on their windows for the winter. Basically, they would stick the saran wrap directly to the glass in order to cover its entire surface.

  • 1
    New Zealand has shockingly bad insulation standards, starting at "none" if the house is old enough. We call it "food wrap" or "gladwrap" if you want the brandname. Saran wrap sounds like something related to saran gas. The plastic often used is slightly thicker and comes in much larger pieces than a roll of food wrap. It is stuck to the frame using double-sided tape (sellotape) not stuck straight to the glass, and then trimmed and gently heated to take out any wrinkles. Has to be applied when the weather is warm and the frame is dry, else condensation.
    – Criggie
    Commented Nov 18, 2015 at 4:30
  • 1
    @Criggie "none if the house is old enough" probably applies to the entire world. I know here in the US insulation wasn't used until maybe sometime in the 50s: My house was built in '47, and there's no insulation. Also, Saran is a brand of food grade plastic wrap that at least common in the US.
    – DrewJordan
    Commented Nov 18, 2015 at 14:20

One really effective way is to add a new pane to the windows. This can be done as a temporary storm window as suggested by Zeiss Ikon on the outside, or it can be done on the inside.

If done on the inside it doesn't demand that much work securing the new pane as the weather doesn't have access to it. This also means you can use simpler arrangement for attaching the extra pane.

So my suggestion would be to buy acrylic glass/plexiglass (4mm?), which can be bought at reasonable prices, and simply use a saw to fit them to the inner frame of your window. This extra layer between the real window and the extra pane will give you some extra insulation.

And if done properly, you can easily reuse the panes the following year. Depending on your handyman skills, you could also attach a simple frame for easier handling.


"Curtains" is too short an answer so I added these extra words. (some curtains are very light fabric that allows some light).

  • If you have a radiator under the window, tuck the curtains behind it. Make them long enough for this. If you are really cash-strapped, pin a sheet onto the wall. You can pull it aside to let light in, or use something translucent. If you use the cheapest material you can find - polyester and stuff, it may not be fire resistant, do be careful.
    – RedSonja
    Commented Nov 19, 2015 at 9:22
  • 1
    @RedSonja: and if you can't make the curtains long enough, at least tack fabric (e.g. from an old sheet) to the bottom of the curtain, enough to tuck behind the radiator and create an airflow that isn't straight up the window. Commented Nov 19, 2015 at 13:39

Put weather stripping on moving parts, and then apply a special plastic film over the window area, trapping a layer of air between it and the window.

Check out "How to Weatherize Windows with Plastic Film Insulation" from Green Dream, for a simple demo of how to do this cheaply.

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