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Green Building Spotlight
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Renovation on the Hill Transforms a 1930s Building, Minimizes Energy Use 


Sustainably Built’s project on a rare Boulder French Eclectic received CGBG’s 2014 Award for Best Green Improvement on an Historic Building

By Kirsten Frysinger

The project at 1101 University Ave. was a renovation of an historic building on University Hill in Boulder. The challenge was to bring an 85 year-old building up to current building codes while making it more livable and preserving architectural integrity. Results included significant energy savings over the original structure, a reduction in the building’s environmental impact, and improved comfort in a healthy living space. The project involved Brickstone Partners of Denver (developer), Studio Architecture of Boulder (architect), and Dohn Construction of Ft. Collins (general contractor). Historic buildings like this one are a big part of the character and experience of Boulder, and reducing their consumption by 70% demonstrates what is possible for both historic buildings and college housing in Boulder.

Historic Significance

This structure was designed by Architect Glen H. Huntington and constructed in 1930-31. Huntington was one of the first professional architects in Boulder who also designed the Boulder Courthouse. The original owner was the Alpha Delta Pi Sorority. The building itself is one of the few examples of the French Eclectic style in Boulder. In 1955, a three-story addition was added to the north part of the building. The existing exterior structure was maintained for both the original building and the addition in their entirety allowing the site to maintain its historic integrity.

HERS 220 to HERS 70

At the start of the renovation project, the HERS rating of one of the eventual apartments was approximately 220, and the City of Boulder required a HERS 70, an almost 70% reduction in energy use. Considerable work was done to reduce the air leakage, a challenge given the original structure of the building and the additional structural work that was done to bring the building to modern standards. Reducing air leakage substantially impacts energy use and occupant comfort, and the attention paid to tightening the building helped achieve the target HERS score of 70. Proper distribution of heating and cooling was also an important consideration for the comfort and health of the buildings occupants. As such, the air ducts were tested to ensure proper operation, as well as measure leakage. The following provides details pertaining to how these results were achieved:

Due to the nature of the wall construction, the insulation differed between the original brick structure and the 1955 addition. As mentioned, insulating the existing brick structure was a challenge, both intrinsically and because of the additional structural support that was added to the building. In several difficult areas, closed-cell spray foam insulation was used to ensure proper insulation and aid in air sealing. High efficiency mechanical equipment, low-e windows, and high efficacy lighting were used as part of the overall strategy to meet the City of Boulder’s HERS requirements.

Building construction:

Foundation Walls: R15 interior in the addition, R13 in the original building

Slab: R10 underslab and R10 2' perimeter for new slabs. Existing slabs were uninsulated.

Above Grade Walls: R19 in the addition. R15 in the original building.

Ceiling: R25 at addition. R39 cavity at existing vaulted areas.

New Windows: U=0.28, SHGC=0.30

Hot Water: 97% AFUE Tankless

Heating equipment: Forced air fancoil (supplied from tankless hot water heater)

Air conditioning: 13 SEER

Lights and Appliances:

Average % high efficacy lighting = 85%

Refrigeration: Energy Star rated

Dishwasher: Energy Star rated

Washer/Dryer: Energy Star rated

Water and resource conservation:

Low flow fixtures were used on all faucets and shower heads

Best Green Improvement on an Historic Building Award

This project was completed in early 2014 and later received the Colorado Green Building Guild Historic Building Award. Much credit goes to the developer, Brickstone Partners of Denver, the architect, Studio Architecture of Boulder, and the general contractor, Dohn Construction of Ft. Collins for their commitment to energy reduction.

Historic buildings like 1101 University Avenue are a big part of the character and experience of Boulder, and reducing their consumption by 70% is a great model for what can be done with historic buildings, as well as college housing in Boulder.

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