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Clearbrook City Hall and Community Center achieved energy savings and enhanced comfort from its recent energy upgrades.

Case Study: City of Clearbrook City Hall and Community Center

Building envelope upgrades save energy, improve comfort

Aims and objectives. The City of Clearbrook City Hall and Community Center building was built in phases during 1953 and 1964. The 19,000 square-foot structure houses the City Hall and associated offices, the Police Department, the American Legion, the City Council chambers, and a community recreation space. The city decided to pursue an energy savings rehabilitation project to improve the energy efficiency and comfort of the building.

Implementation. The upgrades included increasing the insulation value of the roof sections to R-30 and insulating the previously uninsulated walls with spray foam to R-20. The single pane windows (1,120 square feet) were replaced with high efficient units. Also, several inefficient windows (about 700 square feet) were replaced with insulated wall.

“With the grant from the American Recovery and Reinvestment Act, it was financially feasible for Clearbrook to insulate and install new energy efficient windows in our community center, which is the old school building in town,” said Dan Johnson, Clearbrook’s natural gas superintendent. “The saving of 60 percent a year on our natural gas heating load allows the city to keep the history of the old school building around for future generations.”

Outcomes--energy saved, CO2 reduced, comfort enhanced. Comparing the baseline year 2010, before the upgrades were finalized, to 2012, when the project was completed, the building’s electric use decreased 19 percent and natural gas use decreased 60 percent (see figures 1 and 2). Because of these savings, the building’s energy-related CO2 emissions have been reduced by 39 percent.

The Minnesota B3 Benchmarking ratio for the building now stands at 78 percent, meaning it uses about 20 percent less energy than if it were a new building built to current energy codes.

Annual electric consumption

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Figure 1. This chart from the Minnesota B3 Benchmarking database shows City Hall and Community Center electrical savings.

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Figure 2. The chart above shows the actual natural gas use on the red bars and what the consumption would have been without the energy improvements on the dashed line. The dashed line is a projection of the 2010 (pre-project) energy use that has been normalized to account for weather variations. The consumption shown in 2012 is 60 percent below the base year of 2010.

Annual CO2 emissions

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Figure 3. This B3 Benchmarking chart shows CO2 reductions of 36 percent from 2010 to 2012.

Building envelope improvements of wall and roof insulation and window replacement are often a challenge to justify economically based on energy savings alone. But when you factor in added benefits such as enhanced occupant comfort, improved worker productivity, and the elimination of potential mold problems on cold surfaces—benefits that are hard to quantify in dollar figures—then the project looks much better.

Productivity gains? For instance, it’s hard to measure the effect of a building’s improved comfort and aesthetics on worker performance. But research on building retrofits suggests that improving the energy efficiency of a building can result in gains in worker productivity, as well as generate energy cost savings. According to a literature review by the Institute for Building Efficiency, studies demonstrate that comprehensive energy efficiency improvements as well as single-measure upgrades (such as improved lighting, temperature control, air quality, and comfort) can substantially increase productivity. Productivity gains are rarely factored into the financial return-on-investment calculations for energy efficiency upgrades, because productivity gains are difficult to measure.

Documenting results. Clearbrook is able to quantify its savings via Minnesota B3 Benchmarking. The Minnesota B3 Benchmarking tool is available for all state, local government, and public school buildings. To add your building to this database, go to the B3 website and click on “Contact Us.”

Funding: The cost of Clearbrook project was $302,000, with nearly half of the project cost ($150,000) covered by an Energy Efficiency and Conservation Block Grant (EECBG) provided by the Minnesota Department of Commerce and funded by the American Recovery and Reinvestment Act of 2009.

Resources for local government projects. Cities and other public institutions seeking energy efficiency improvements are encouraged to consult with the Minnesota Department of Commerce, Division of Energy Resources (DER) and their local utilities. DER provides technical support to local government units, state agencies, school districts, and institutions of higher learning that are seeking energy efficiency and renewable energy measures. Contact DER to discuss which of its energy efficiency programs can be of help.

Utility representatives can help assess opportunities for efficiency and identify rebates to help finance projects. Utilities in Minnesota are mandated to achieve an annual energy savings of 1.5 percent of annual retail energy sales. Energy improvement projects such as Clearbrook’s help achieve that energy savings requirement.

The U.S. Department of Energy provides helpful resources for building retrofits, including “The Advanced Energy Retrofit Guide for Office Buildings.” For more on energy efficiency, including information on Minnesota’s B3 Benchmarking tool, contact the DER Information Center at energy.info@state.mn.us or 800-657-3710.