FAIRBANKS — The “Ask a Builder” series is dedicated to answering some of the many questions Fairbanks residents have about building, energy and the many other parts of home life.

Windows are the weakest point of the building envelope. As Interior Alaskans know, poor windows can fail easily in the winter, losing heat, frosting up and letting in cold drafts.

The Cold Climate Housing Research Center created the Certified Alaska Tough program to help consumers identify windows that can withstand the extremes of Alaska.

Based on today’s fuel costs, replacing existing double-pane windows with Certified Alaska Tough windows will save Fairbanks homeowners roughly $700 per year. 

Because they must demonstrate extremely low air leakage, the windows also prevent cold drafts.

To become certified, windows must pass tough criteria developed by CCHRC and tested by a third-party laboratory. That includes stringent standards for strength, insulation and air tightness.

Breaking it down

Certified Alaska Tough windows must have a U-value of 0.2 or less (equivalent to an R-value of 5). U-values measure the window’s overall effectiveness against heat loss and are the inverse of R-values, with lower numbers indicating better insulation.

To put this into context, Energy Star windows in northern climates are required to have a U-value of 0.27 or less. A U-value of 0.2 was chosen for the Alaska Tough program because it is the highest level of thermal comfort that can be produced with current technology at a reasonable price.

In addition, windows must have an air leakage rate of less than 0.1 cubic feet per minute per square foot (for windows that open) and 0.04 for fixed windows (compared to Energy Star rates of 0.3 cfm/square foot). This ensures windows can withstand wind washing and chilly drafts.

Capitol Glass Northerm Windows is the first company to meet the new standard, now offering five windows that are Certified Alaska Tough.

For more information on the program, visit http://www.certifiedalaskatough.org or contact CCHRC at info@cchrc.org or 457-3454.

“Ask a Builder” articles promote home awareness for the Cold Climate Housing Research Center (CCHRC). If you have a question, contact us at info@cchrc.org or 457-3454.