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Interior Storm Windows

Interior storm windows are one of the great success stories of the Midcoast Green Collaborative. They were introduced by Topher Belknap at the 2nd Annual Midcoast Sustainable Living Expo, and have been modified, improved, tailored, and run rampant since them. We estimate that over 20,000 windows have been made by, and for, Mainers since then, and there are groups now in other parts of the Country, and in Hungary and England making them.

The Design

window without storm
Window without storm
photo credit: Guy Marsden

The idea of the windows is simple. A wooden frame is made about ½ an inch smaller than the window frame it is to go in, and that frame is covered on both side with pieces of heat-shrink (polyolefin) plastic. Tape is used to cover the edge, the film is shrunk with a hair dryer, and a ½ inch foam weather striping is added around the edge. The storm is then inserted in the window frame for the winter, and removed for storage over the summer

We generally make these storms with pre-primed pine, but most any wood will do, provided it is structurally sound. Scrap or #3 pine is fine for basement windows for example, or using clear wood, or painting the wood to match the existing trim, will make the storms even less conspicuous.

Simple instructions or a 2 page PDF version .

An exhaustive website with pictures, material suppliers, and a spreadsheet for material costs.

Here is a Google Sketchup plan for the storms, and hereit is on the Google 3D Warehouse. Hiding various components will allow the construction details to be discerned.

The Benefits

window with storm
Window with storm
photo credit: Guy Marsden

Interior storm windows have an R-value of around 2.3 and will reduce the air leakage from a leaky window. They also reduce outside noise. However, they do reduce the amount of incoming solar heat (SHGC 0.86), which while not a benefit in the Maine (and many other places) climate, it is a reasonable compromise, and the storms on the whole are a benefit.

The actual benfits you get will vary depending on your climate, cost of heating fuel, and type and condition of your windows. But broadly, if you have single pane windows (and no storms), the simple payback time will be under 7 months. In other words it is cheaper than buying fuel this year. And the benefits will continue for years to come. For single pane windows with aluminum storms, the payback is around a year. For good double pane windows around 2 years. For Andersen's best energy-star rated lowe-4 windows, the payback is still around 4 to 5 years. Only if you have super high-efficiency triple pane, lo-e, gas filled windows (or better) do these storm not make good sense.


MGC sponsored workshops
We are currently looking for a new location to hold the workshops. Watch this space for more information.

Buying Interior Storm Windows

Topher Belknap, a MGC member, makes these as a part of his business Green Fret Consulting. He also makes a triple pane version for tough applications like single pane windows, or very large windows.

Topher also make kits (with or without the wood), which can be shipped, or picked up, and he sells all the materials. Contact him for more information.

Window Dressers works out of Rockland, producing many windows. They are a non-profit Corporation with the goal to: Reduce fossil fuel consumption, Reduce the cost of residential heating / cooling, Reduce CO2 emissions into the environment, Provide help to low income Mainers in heating their homes.

If you are making these interior storm windows for sale, we would love to hear about it, and will gladly put the relevant information here.

Other News

This is a sing-out from Bill McKibben at 350.org