BONNEVILLE POWER ADMINISTRATION
A new window of recognition for BPA and partners on an emerging technology

An alternative to storm windows earns high marks for providing comfort, energy and cost savings in a Vancouver, Washington demonstration. Regional roll-out has already begun.

Together with the Northwest Energy Efficiency Alliance and Clark Public Utilities, BPA has received recognition from the U.S. Department of Energy's Building Envelope Campaign for a joint venture demonstrating secondary windows, an emerging technology.

BPA's Emerging Tech intervenes in the market adoption by demonstrating and quantifying energy savings values so program incentives can be developed for BPA customers.

BPA mechanical engineer Jamie Anthony

These are not your grandparent's storm windows
Poorly insulated windows often contribute to high electric bills and poor temperature control in commercial and residential real estate. Replacing windows has been expensive and disruptive to the occupants. Often this requires removing the glass, the frame, and the surrounding drywall, before inserting the upgraded product, repairing the damaged drywall, and applying a new coat of paint. But recently BPA partnered with NEEA to field test a different approach. Inserting a secondary window into the existing framework creates an additional air barrier, while ensuring there's a small amount of space to prevent convection. The result is conserved energy and increased comfort with less mess.

Vancouver case study
The case study that earned the project recognition from DOE is an office building in downtown Vancouver, Washington. With the 5-story, 6,000-square-foot, all-electric commercial building closing in on its 50th anniversary, the property managers were looking for ways to improve building comfort and performance. They identified the building's floor-to-ceiling single-pane windows as a place to start. While occupants appreciated the expansive views, they were uncomfortable - too hot in the summer and too cold in the winter. Watch the project recap video on YouTube.

This upgrade has proven to be three-to-four times more efficient than the previous single-pane windows, cost a fraction (one-seventh) of a total window replacement, and took only two weeks to complete. The benefits are clear: save energy, improve comfort, minimize air leakage, and even reduce noise pollution. Plus, the work could all be done internally, so no 5-story construction cranes were needed. Since the upgrade, the building at 915 Broadway has seen 10-15% energy savings for the whole building.

Remember the heat dome Portland and Vancouver experienced in the summer of 2021? While it was 116 degrees outside, the building remained a comfortable 72 degrees inside. Previously, if the temperature climbed above 90, the occupants would go home because the building would be too warm. No longer. Happy tenants. Happy building owners.

This project is one example of how BPA, its customers and NEEA work together to identify new energy efficient technologies for the built environment. 

"The building owner realized a lower electricity bill while Clark and Bonneville realized the savings potential of this emerging technology," said Bill Hibbs, Commercial Programs and Key Account Manager for Clark Public Utilities. "This project was the epitome of a win-win."

Windows emerging tech receives national recognition
DOE recognized this work with a national award, presented to the team in late August. The Building Envelope Campaign works with stakeholders across sectors to advance the market adoption for both primary and attachment window products.

"Window attachments currently have a high cost and need utility incentives and market disruption to bring down the cost," says BPA mechanical engineer Jamie Anthony. "BPA's Emerging Tech intervenes in the market adoption by demonstrating and quantifying energy savings values so program incentives can be developed for BPA customers."

These windows not only provide comfort and energy savings, but they also support grid resilience because they reduce power use associated with heating, ventilation and air-conditioning.

"The NEEA and BPA partnership has resulted in a new incentive and program offering for our utility customers," Anthony said.

Secondary windows are ideally suited for historic buildings since they do not alter the exterior building facade and often have single-pane clear glass windows. The challenge for utilities may lie in identifying these properties, but once identified, this new measure offers an opportunity to provide occupant comfort year-round and major savings in energy costs.