Milwaukee Milestone: A Zero-Net Case Study
- Oct 07, 2016
By Alexandra Pacurar
For most apartment dwellers, the first thing that electric service brings to mind is a monthly bill. For residents of two new multifamily projects on Milwaukee’s East Side, electricity counts as merely another amenity. Developed by a hometown multifamily specialist, Dominion Properties, the two communities are believed to be the first residential properties in Wisconsin to employ ground-source heat pumps, and are rare examples of large-scale residential solar installations in the city.
“We are not aware of any other residential housing in Milwaukee that uses ground-source heat pumps,” said Mike O’Connor, principal & CEO of Milwaukee-based Dominion Properties. The use of solar panels on residential housing projects is also very limited, he noted. “We are not aware of any installations on residential housing as large as the ones that we feature. The goal is to reduce the carbon footprint of every residence.”
Recently opened at 1825 N. Prospect Ave., the five-story Sage ON PROSPECT has a 29 kilowatt-hour rooftop installation that generates power for common areas, lights, elevators, HVAC and electric car chargers. The solar panels cool and heat the building at no charge to the residents. “We estimate that these arrays will offset 95 percent of the buildings’ usage at peak sunlight, when the demand on AC is the highest,” O’Connor said. An added amenity is complimentary Internet service.
Sage ON PROSPECT’s power system also includes a 95 percent efficient boiler that serves as a backup heat source and provides on-demand heat to parking areas. In concert with an innovative cold-water tempering tank, the boiler supplies hot water to residents while producing minimal carbon emissions.
Sage ON PROSPECT is the second zero-net-energy property developed by Dominion. Two years ago, the firm completed Sage ON JACKSON, a 20-unit community at 1509 N. Jackson St. Sage ON JACKSON was the first multifamily project in Wisconsin to earn Platinum-level LEED for Homes certification.
For both the Prospect Street and Jackson Street sites, Dominion received grants to defray the cost of the solar installations from Focus on Energy, a statewide energy efficiency and renewable resource initiative. The program is funded by Wisconsin’s investor-owned utilities and participating municipal and cooperative utilities.
Down to Earth
Both Sage communities draw on renewable energy from the earth as well as the sun. Wells extending 400 feet below the surface supply geothermal energy that heats and cools the properties. Sage ON PROSPECT employs 24 of the wells, while Sage ON JACKSON employs 18.
As with all geothermal systems, the interaction of the ground and the heat pump provides the energy transfer that warms the units in the winter and cools them in the summer. The system circulates a water-based fluid that flows to a heat pump in each unit. “Think of it like an air conditioner that works in both directions: one way to heat and the other to cool,” O’Connor explained.
In addition to having an innovative energy strategy, Sage ON PROSPECT is an adaptive reuse project. Its three lower floors date from the early 1960s and originally served as a nursing home. Taking note of the unoccupied building’s sturdy steel, concrete and masonry structure several years ago, Dominion saw its potential. In many ways, demolishing the building and starting from scratch would have been easier than undertaking an extensive adaptive reuse project, O’Connor observed.
“But we wanted to preserve the structure that is made so well and features a nice Cream City-style brick,” he explained. Dominion renovated the existing three floors and added two new levels. “The new structure we built on top has steel siding and balconies.”
In another act of repurposing, Dominion brought in hardwood floors formerly used in a gymnasium at the University of Wisconsin-La Crosse campus.
Besides its focus on energy, Dominion incorporated a variety of sustainable measures intended to enhance resident health. Its hallway carpeting, for example, is chemically neutral and engineered to capture dust tracked in from outdoors.
Other green features include low-odor vinyl floor planks and mineral wool rather than Fiberglas for insulation. The owners also chose paint that is free of hazardous volatile organic compounds. Living-room fireplaces use energy-efficient LEDs rather than actual flames, which generate carbon. Bathrooms are equipped with silent fans that rotate constantly to improve air quality.
Sustainability figured into the selection of washers, dryers and furnishings, as well, O’Connor reported.
“As part of the LEED program and the Sage brand (policy) of buying American, the significant majority of the Maytag and Whirlpool appliances are all made domestically, within a certain distance to reduce shipping, which requires burning carbon (with the exception of the microwave),” he said. “All the wood cabinets are from Wisconsin vendors.”
This is one of three case studies on green residential development featured in MHN‘s October issue. Be sure to read the other two case studies, featuring zero-net development in Los Angeles and the world’s tallest building designed to passive-house specifications!