Beneath the parking lot of East Anchorage's new Creekview Plaza lies the heating source for the entire complex.
About 10 feet below the asphalt lies a series of glycol-filled tubes, which absorb energy from the relatively cold water in the ground to heat 49 units in two buildings.
It's the first time alternative-energy ground-source heat-pump technology has been used on a large scale in an Anchorage building.
Individual heat pump units are rare in Anchorage, because natural gas is an abundant and low-cost energy source in the area. But in places without natural gas like Fairbanks, Seward and rural parts of the Mat-Su, more heat pumps are being installed as a heating source.
The Alaska SeaLife Center in Seward uses a similar technology that pulls energy from water in Resurrection Bay to heat its building, saving thousands of dollars in energy costs each year.
At Creekview Plaza, every unit has its own heat pump, according to Brent Hove, project manager with Cook Inlet Housing Authority. The systems are inconspicuous, hidden behind a ceiling panel in each apartment, with each unit connecting to a bore hole in the parking lot. The pumps can provide heat or cooling.
Hove said the authority went with the technology in order to comply with grants that require investments in alternative energy. Along with the heat pumps, the six-star energy-rated building also has solar panels.
Whether the pumps will work in extreme cold weather remains to be seen. The glycol loops pull energy from the ground that's essentially recharged by heat from the sun over the summer. That can make it harder to run the heat pumps in the spring, after heat has been absorbed from the ground over the winter. A backup natural gas boiler is on site in case there's a malfunction with the heat pumps.
Hove said so far it's worked. The water in the ground has been around 48 degrees, warmer than expected.
Chuck Renfro installs ground-source heat-pumps in Alaska and worked as a consultant on the project. He said he's seen applications for the technology in parts of Anchorage that aren't connected to natural gas or where homeowners are looking to offset their carbon footprint.
The authority also installed a ground-source heat pump for a senior housing project in Seldovia, where there isn't natural gas available and heating oil for homes and businesses is expensive. But the Seldovia project is smaller — a single system for one building.
Hove said the payback period — how long it will take for the system to begin saving owners money — on the Seldovia project is seven to eight years. For the Anchorage project it's closer to 17 to 18 years because of natural gas prices.
But project architect Tamás Deák said the building is designed to last 60 years, well beyond the payback for the heating system.
"If you look at the lifecycle cost of running this, you're way ahead of the curve," he said.
Betty Harper moved into the unit on Aug. 31. In an interview last week she had no idea alternative energy was being used to heat the apartment.
She shares a two-bedroom apartment with her son Robert Kaldor and keeps it at 75 degrees. Harper, 77, has a heart condition that requires her to keep the house warm.
In the three weeks she's lived in there, she said, she's had no trouble with the heat. She likes that it comes through vents in the ceiling instead of forced air or baseboard heat. She's said her apartment is comfortable and cozy.
And she appreciates the cost savings. Her electric bill for 13 days was only $9.95.
"Hopefully it stays like that," she said.