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Tightening up Windows to Increase Energy Savings

The Old House Web

windowTightening up your windows can save you money on heating and cooling. From the Michigan State University Extension Service, here are some tips on weather-stripping and buying storm windows.

(Here is a detailed OHW story on double-hung windows construction. Here are also some related stories on insulation and weatherstripping. )


Window types:

  • A sliding window can be treated as a double-hung window turned on its side.
  • Casement and tilting windows should be weather-stripped with the vinyl nailed to the window casing so that, as the window shuts, it compresses the roll.

When to use foam:

  • Install adhesive backed foam, on all types ofwindows, only where there is no friction.
  • On double-hung windows install only on the bottom and toprails.
  • Other types of windows can use foam strips in many more places.


  • Before applying caulking compound, clean area of paint build-up, dirt, or deteriorated caulk with solvent and putty knife or large screwdriver.
  • Drawing a good bead of caulk will take a little practice. First attempts may be a bit messy.
  • Make sure the bead overlaps both sides for a tight seal.
  • A wide bead may be necessary to make sure caulk adheres to both sides.
  • Fill extra wide cracks like those at the sills (where the house meets the foundation) with oakum, glass fiber insulation strips, etc.) In places where you can't quite fill the gaps finish the job with caulk.
  • Caulking compound also comes in rope form. Unwind it and force it into cracks with your fingers. You can fill extra long cracks easily this way.

Storm Windows

Installing storm windows will increase the energy efficiency of your windows.

  • Triple track, combination (windows and screen) storm windows are designed for installation over double hung windows. They are permanently installed and can be openedany time with a screen slid into place for ventilation.
  • Double-track combination units are also available and they cost less. Both kinds are sold almost everywhere, and can be bought with or without the cost of installation.

You can save a few dollars (10% to 15% of the purchase price) by installing the windows yourself. But you'll need some tools:

  • caulking gun
  • drill,
  • andscrew driver.

In most cases it will be easier to have thesupplier install your windows for you, although it willcost more.

The supplier will first measure all the windows where you want storm windows installed. It will take anywhere from several days to a few weeks to make up your order before the supplier returns to install them. Installation should take less than one day, depending on how many windows are involved.

Two very important items should be checked to make sure the installation is properly done.

  • Make sure that both the window sashes and screen sashmove smoothly and seal tightly when closed after installation. Poor installation can cause misalignment.
  • Be sure there is a tightly caulked seal around the edge of the storm windows. Leaks can hurt the performance of storm windows a lot.

What to look for when buying storm windows

Frame finish

  • A mill finish (plain aluminum) willoxidize, reducing ease of operation and degrading appearance. An anodized or baked enamel finish is better.

Corner joints

  • Quality of construction affects the strength and performance of storm windows.
  • Corners are a good place to check construction. They should be strongand air tight.
  • Normally overlapped corner joints are better than mitered. If you can see through the joints, they will leak air.

Sash tracks and weather-stripping

  • Storm windows are supposed to reduce air leakage around windows. The depthof the metal grooves (sash tracks) at the sides of thewindow and the weather-stripping quality makes a big difference in how well storm windows can do this. Compare several types before deciding.

Hardware quality

  • The quality of locks and catches has a direct effect on durability and is a good indicator of overall construction quality.


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