Bonneville Power Administration
|BPA Home EE Home Energy Tips Do-It-Yourself Home Weatherization Guide Storm Windows and Sliding or Insulated Doors|
Storm Windows and Sliding or Insulated Doors
Glass is an ineffective insulator; single-pane windows lose a lot of heat. Storm windows work by providing a "dead air" space - usually of 1 to 4 inches - between the prime window and storm window. This dead air works like insulation, slowing heat flow between the house and the outside.
Storm windows should be made of glass and permanently installed. The main sash should be easy to open and remove or access for cleaning.
Windows of this type ("multi-track" construction or multi-glazed replacement windows) are available in kits for standard-sized windows at building supply stores. Unusual sizes can be built to your specifications by an experienced contractor. Usually storm windows are professionally installed. You should only choose to install them yourself if you have good carpentry skills. Poor installation causes breakage, inefficient heat loss protection, and often added expense to have a contractor re-do the job.
Fig. 8.1 shows where to install common storm window types.
If your home has skylights, you may want to weatherize them, too. If cost-effective, single-glazed skylights may be replaced entirely with double-glazed skylights. Caulk between the roof and the skylight mounting flange after installation (Fig. 8.3).
Insulated doors are installed in place of the existing door, so they are more cost-effective than a storm door if the existing door is damaged or needs replacing. Depending on the strength of the existing door casing, these may be either completely pre-hung units or the door only. Your utility will help determine if the prime door needs replacing and provide information on the type of door to purchase.
Sliding Glass Doors
Sliding glass door storm door add-ons, double-glazed inserts to replace glass in existing doors, and complete double-glazed replacements are made for sliding glass doors. They all require good carpentry skills to properly install.
Storm door add-ons are usually mounted on the outside of the house siding and are difficult to seal properly. Weather-stripping is required on both the original and the secondary door. Screen doors should be included.
The insert type is perhaps the easiest to install. The existing door must be removed, carefully disassembled and the glass replaced with the custom-made glass inserts.
Full double-glazed replacements usually require that the entire door and frame be removed and replaced. This requires the temporary removal of some house siding around the door opening and, sometimes, slight modifications of the door opening itself to make the new door fit. Installations must be square and plumb, or the door will not function properly.
Double-glazed sliding glass doors should be installed by a contractor.
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