Procedures For Selection And Proper Installation Of Windows

Windows provide light and fresh air into a home -- with proper selection and installation, windows can make homes more comfortable and reduce costs for heating and cooling. The purpose of this document is to ensure that the energy-efficiency features of windows are considered in their selection and that they are properly labeled and installed. The home will not be as comfortable and energy costs will be increased if both U-value and shading coefficient (or solar heat gain coefficient) are not considered, or the windows are installed incorrectly, such as being installed without proper air sealing.

Background: Recent studies have found that a quarter of new homes have higher U-value windows (less energy efficient) installed than specified and almost half have problems with their labels. In addition, there are new types of glass that are virtually clear but that provide similar shading to having a roller shade pulled closed. This kind of glass can be a very cost-effective energy feature in areas that require significant cooling.

Use of these Procedures: The purpose of this document is to provide the tools to ensure window are properly specified and installed, resulting in a comfortable, energy-efficient home.

Builder: Include these materials in your bidding and contracting documents. It is meant to form the basis of a scope of work for both bidding and contracting. Its use will help ensure consistent bids and quality installations. Attachments W-1 (windows) and W-2 (sliding glass doors) contain detailed installation procedures to be followed by the window installer.

Contractor: Follow Attachments W-1 (windows) and W-2 (sliding glass doors) for installation.

Field Superintendent: Verify Attachments W-1 and W-2 are followed.

Criteria for Quality Windows

Windows should:

1. Provide a thermal barrier between the inside conditioned space and the outside,
2. Be installed to the proper U-value and shading coefficient or solar heat gain coefficient (SHGC),
3. Be properly labeled,
4. Be properly sealed and flashed to avoid air and water leaks.

Procedures to Install Windows for a Quality Thermal Envelope

The following steps should be followed in the installation of insulation to ensure efficiency and comfort (for details, see Attachments W-1 and W-2):

1. Work with the architect and energy consultant to choose optimal U-value and SHGC windows.
2. Use windows that are tested and labeled with proper U-values and SHGCs.
3. Install windows with U-values and SHGCs that meet or exceed design specifications.
4. Install windows with proper sealing and flashing to avoid air and water leaks.

WINDOW INSTALLATION PROTOCOLS:

EACH MANUFACTURED WINDOW MUST:

• be tested according to ASTM E283-91 procedures and certified to not to leak more than 0.37 cfm/ft of operable sash crack
• be certified as to its overall U-value as rated in accordance with the National Fenestration Rating Council's procedure, or in accordance with the default table method approved by the California Energy Commission
• have a temporary label, not to be removed before inspection by the enforcement agency, listing the certified U-value and certifying that the air leakage requirements are met
• have a permanent label listing, or providing the means for determining, the U-value, certifying organization, and rating procedures.

Site-built doors and windows must be caulked and weather-stripped.

The window installer or distributor must complete and sign the Installation Certificate (CF-6R) for fenestration.

Detailed window and sliding glass door standard practices are in Attachments W-1 (windows) and W-2 (sliding glass doors).

Attachments W-1 and W-2 provided courtesy of The Building Industry Institute - www.thebii.org

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eehomes@energy.state.ca.us