What is the most economical and energy-efficient way to winterize windows?

Question

We have vinyl windows (mostly double-paned) and live in a shady greenbelt in Seattle (i.e. wet and dark). We don't have much severe weather to worry about, just a pervasive damp cold that settles in and makes our extremely inefficient remodeled money pit cost a fortune to heat.

I've looked at rolls of plastic for window sealing at Home Depot and Lowe's and have been surprised at the cost, considering it's just a roll of plastic. Is this the most efficient option? Are there ways to winterize that involve materials that could be re-used next winter?

Any advice appreciated!

Answer 1

As Tester mentions, new windows are the most cost and energy efficient in the long haul. However, the upfront cost is substantial, especially if you want to do a lot of windows.

The concept is the same with all window coverings, add an additional layer of air between the primary window and the covering to slow down the transfer of heat. A single pane window is generally .85 r-value. Verifiable r-value numbers are hard to come by for most of these products, but if you do find some, that will give you a basis for comparison.

Other options:

• Storm windows. This is basically installing a secondary window on the outside. These can be quite expensive, or cheaply made using plexiglass. They are cheaper than new windows, reusable, and transparent. The drawback is that there is still a sizable upfront cost and you have to store them somewhere in the summer.

• Secondary glazing. Same idea, except installed inside. Similar advantages and disadvantages to storm windows. They tend to be much thinner and don't change the look of your house.

• Cellular shade. There are some interesting claims with cellular (honeycomb) shades, some claiming to add well over 2 r-value to a window. These will darken the room some and are still quite expensive.

• Window film. This is the cheap option, unless you have curtains laying around. The main drawback is that it's generally opaque and it's more difficult to reuse year-to-year.

• Heavy curtains. Tried and true method used for centuries. Obviously you won't be looking out these windows.

Answer 2

In the winter, windows can be one of the biggest sources of heat loss in your entire house. In an older house with no or low insulation, this can be particularly true.

One thing that you can do with minimal fuss - if you feel cold drafts coming from around the window its entirely possible that you've got air leakage around the window frame itself. A quick test to determine whether this is true or not is to light a candle and hold it about a foot from the window, and slowly move it around the border of the window. If you see that the candle's smoke is significantly disrupted, you can add spray foam insulation around the perimeter of your window.

1) CAREFULLY remove the trim around the interior window frame so you end up with a window like this:

2) If there is an obvious gap between the window sash (the wooden frame around the window) and the structure, use some canned spray foam insulation and carefully spray foam into the gaps to create an air tight seal. DO NOT OVERFILL as the foam will expand.

You want the foam to end up looking like this:

Give the foam AMPLE time to cure - give it a good 24 hours - and then use a straight serrated knife to cut any squeezed out foam off level with the wall.

How the window may look prior to trimming back the foam:

Finally, reattach the window trim like it was before.

Answer 3

I agree that it is important to make sure the windows are sealed and properly weatherstripped. All windows regardless of age transfer a lot of heat. With some older windows and in older houses, the discomfort that a lot of people feel is actually air transfer moving through the windows. Sealing gaps (if you have new windows but the old weight cavities are still open, for instance) makes a big difference. Old doors also move a lot of air - you can seal these with felt stripping (the old fashioned way) or spring loaded weatherstripping, or self adhesive foam or rubber.

Also, make sure your home is properly insulated and sealed. This means sealing outlet and light switch cavities, as well as ceiling lights (believe it or not, a lot of air transfer goes through these areas). Switches are insulated using very cheap foam rubber gaskets that simply fit behind the switch plate.

You can make storm windows using plexiglas and lightweight wood frames to mount either on the inside of your windows (you can buy these too for more money - see sites like innerglass.com) or for the outside. During the summer you will of course have to store these.

Answer 4

What are you using to heat the house with? I notice a lot of houses in Seattle use electric baseboard. That's probably the most expensive way to heat (unless you are diligent and turn them on/off as you go from room to room throughout the day).

So new windows may absolutely be a good thing, but if the goal is to save money, you might get better bang for the buck upgrading the heating system first to gas.

Many have mentioned storm windows. I don't know the PNW that well, but in the midwest it's quite common to have permanently installed storm windows with panes that open/close. They can be purchased for about $100 per window. That might be a compromise solution to tearing out all the windows and replacing them.