Is there a significant benefit to using plastic window insulation year round?

Question

In order to help save more money and funnel more of those savings to debts, I'm looking for more ways to save money.

I've heard that puting plastic window insulation over single-pane windows typically found in older houses can reduce utility bills by up to 50%.

But I'm wondering, it's February, and I'm in Portland, Oregon, USA. Summers can get as hot as 100 degrees fahrenheit in the extremes. Living in a temperate climate, is there an advantage to keeping the plastic up year round, or will I just need to remove it in the Spring/Summer?

To further clarify and address the "airing out the house" issue, let's say that I only open two windows upstairs and two windows downstairs. There are 14 windows total in the house, plus 1 door upstairs and two doors downstairs, one in the front and one in the back.

My motivation for asking is to determine if the inputs I put in now in the form of putting up all that plastic in February will pay any dividends, or if it's best I wait until October.

Answer 1

Single pane windows are horribly inefficient. Having the plastic up will pay dividends for the remainder of the winter and if you use AC in the summer it will help there as well. As for airing out the house when its a nice day, you could just remove the film from a couple windows to get the airflow going.

Answer 2

If the plastic reduces air exchange between your home and the outside world in the wintertime, it will do the same thing for you in the summertime. You will get some benefit from the plastic in the summertime. I can't tell you how large of a benefit. But, based on my own experience, the tape that holds the plastic in place tends to grow loose after a season or two, so the quality of seal will deteriorate and you may find yourself having to put new plastic up anyway to maintain the seal.

Also, in my home (1921 with single pane windows) the impact of the plastic could not really be measured in terms of utility bills. It was nowhere near 50%. You will probably find that it makes the room much more comfortable, though.

Answer 3

The plastic will help you in the winter, but it's pretty much useless in the summer. Sunlight on the roof and coming through windows is a far bigger issue than heat exchange in the summer (45-55% of the cooling load in air-conditioned homes) and window plastic won't help with that. It will help stop air leaks, but you can do that with cheap caulk and weatherstripping without sacrificing the ability to open the windows. In the summer, you'll be better off putting up cheap awnings to shade south-facing windows. Save the plastic for next winter.

As for the plastic's effect on utility bills, I don't see how it could cut your total costs by 50% unless every part of the house but the windows is absolutely perfect. It might cut your window-related costs by 50% in winter, but windows are far from the only source of energy waste in any home. The walls, floors, and ceiling probably account for more air leakage than the windows, although those leaks are usually not as obvious.

Answer 4

Starting with the assumption of 50% savings, the implication to me is that the windows are very leaky - letting a lot of air pass. That's because even a new window with insulated glass would not be expected to make that big of an impact based solely on the insulation value of the glass assembly or, in this case, the insulating plastic does not add that much to the insulating properties window. Sealing the places where air leaks through the window assembly would have a bigger effect. (By the way, you'll notice on the site to which you linked, that part of the promotion is that this product can help stop air leaks). The plastic film could be installed over the entire window all the way to the surrounding trim or even the wall and that would prevent air from passing in and out of the house. But there is a better way. Depending on your specific window, you should be able to find various types of weatherstripping materials that allow the windows to operate normally and can stay in place for years. That would be well worth the effort. If you like, tell us more about your particular windows.

Answer 5

Yes! People will think you are a shut-in.

• Solicitors will not come to your door, thereby less drafts.

Yes! People will think you are growing something or hiding illegal activities.

• Neighbors will gossip, about drug activity, maybe even mention things to police - free security.

Any possible thing you put in front of your window is going to keep the outdoor temperature from coming in. Aluminum foil, plastic, trash, bookcase, whatever. Some will do a better job than others. Some will do so while making your window usable like weatherproofing strips. Others make it almost completely non-functional - like plastic. What is the R value in your plastic - well that depends on how thick the plastic is, what its made of, and the tape job around it. Will your energy bills be less - Yes. Whatever you put up will make your energy bill less. Maybe a few pennies a year maybe a few hundred dollars. Maybe the body heat produced thinking about this and putting up the plastic saved more than the plastic itself. I seriously doubt 50% unless you had some very drafty windows.