Question

Do storm windows on older historic homes work well? Reluctant to replace with vinyl dual-pane.

Asked by Anne Greenblatt
Petaluma, CA

We're considering purchasing a Northern California home built in 1909 with original windows and no insulation. Concerned about cost of energy retrofits.

Answer

Florian Speier

Answered by Florian Speier

San Francisco, CA

Zeitgeist Sustainable Residential Design

July 14, 2011

The answer to your question depends on your motivation to use storm windows rather than new windows. In most cases, consumers want to either:

  • save money over new windows, or 
  • wish not to demolish original, historic windows in old and maybe even listed properties.

Storm windows have limited value

The U.S. Department of Energy has a primer on the subject that makes a variety of good points.

In short, the performance of storm windows is limited, and is mainly related to sealing the window better. The additional glass pane does relatively little.

Three alternatives to storm windows

If the reason you are considering storm windows is the budget, interior storm windows may be an option for you, but they won't come close to these alternative approaches:

Restore. You can restore your old windows, which typically includes stripping all the paint, modernizing the sliding and sealing mechanism, and upgrading the glass panes to dual pane.

This is the most expensive, but most historically correct option and it can yield substantial energy savings if done correctly. Some cities, including my hometown of Louisville, CO, will cover 100% of the cost of this option if you agree to list your house as a local landmark in exchange.

Replace. You can replace your windows, preferably with windows from a company that has experience in quality windows that match old homes.

  • I would strongly suggest you use wood windows again if your original windows were wood, and shy away from vinyl alternatives.
  • Besides being environmentally highly problematic, vinyl (and fiberglass) windows will severely degrade the architectural expression of your house, no matter that the salesman claims it looks just the same.
  • Another caveat of replacement windows is the trend in the industry to use so-called fake divided lights. Fake divided lights are strips of plastic between the panes of double pane glass that are supposed to simulate the look of an old fashioned divided window. While this is a cheap way to do it, the results are highly disappointing. Please insist on true divided lights.

An inside window. A third option is to install a completely independent window on the inside of your existing window.

  • This option is only viable if you have relatively thick walls, so there is enough space inside the window opening. 
  • This way, you get the performance of a new window but keep the look and feel of the old window towards the street facade.
  • This option is also expensive, because in addition to the cost of the new window you will still need to maintain your old windows.

 

For more information:

Read "We need to replace the windows on our home. What's the greenest choice?" a Q&A answered by Daniel Glickman.

Tagged In: energy efficient window

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