Metro DetroitOctober 16, 2013
Around for decades, geothermal units can reduce utility bills
By Kristyne E. Demske
C & G Staff Writer
This home on Jefferson Avenue in St. Clair Shores has geothermal units installed to heat and cool it, instead of a gas furnace.
Construction equipment spreads across the yard, and while the roof and some siding are on, it’s apparent there is more to be done to the home on Jefferson Avenue.
From the outside, it looks like a typical construction project. But the way its new family will get through the winter’s cold sets it apart from most buildings in the area.
That’s because, as the big sign proclaims out front, the house being built by Tom Robinson, of St. Clair Shores, will be heated and cooled with geothermal energy.
Geothermal heat provides a 70 percent savings over a gas heating system, according to Charlie Granzow, the owner of Executive Heating & Cooling Inc. in Lake Orion, which is installing the home’s heating and cooling systems.
And there are other advantages.
“You get a more even temperature. You don’t have to worry about carbon monoxide because you’re not using any gas; you just have a compressor,” Granzow said.
Geothermal units can be added to an existing home or built into new construction. They work by bringing heat up from the ground and through a compressor, which then pumps the air into the ductwork of the home. The process is reversed in the summertime to remove heat from the home.
A system of pipes is laid into the property to tap into the geothermal energy. Horizontal pipes that are laid 6-7 feet below the ground require a lot of yard space but are less expensive. Without a large piece of property, a company can still install a unit, but it requires drilling vertically 150-200 feet into the ground.
“Once the loops are in, everything is buried under the ground; you don’t see anything when you’re done,” Granzow said. “You can plant trees or anything back over that. You’ll never see it.”
From the yard, the manifolds fuse into two larger lines, which head into the basement of the house and flow into a circulation pump. The outside lines are filled with an antifreeze solution and use smaller pumps to circulate the fluid through and extract heat from the ground for pumping into the house, “or absorption, depending on whether you’re in heating or cooling mode.”
Sixty percent of the home’s domestic hot water can also be heated with the geothermal energy for free while the unit is running in heating or cooling mode, Granzow said.
There is a significant price difference between a conventional furnace and a geothermal unit, but it is recouped quickly, according to Granzow.
A 90 percent efficient gas furnace and air conditioning unit for a 2,500-square-foot home would cost about $10,000-$12,000 to install, he said. A horizontal loop-through geothermal unit for the same size home would cost $20,000.
But, he said, a federal tax credit of 30 percent of the gross amount of the project is available to help defray the cost. With that, the out-of-pocket cost drops to about $14,000, and the geothermal unit will give the homeowner a 70 percent energy savings per year.
“Your payback’s going to be two-three years,” he said.
In building the home on Jefferson Avenue, north of Masonic Boulevard, Robinson said they were trying to put everything they would need into one home. A geothermal heating and cooling unit was one of those features.
“There’s a significant upfront cost for the geothermal, but this home we expect to live in for some time,” he said.
One of the reasons more people don’t turn to geothermal heating and cooling, despite the significant savings on energy bills, is how much property is needed for the geothermal field, he said.
His lot is 100 feet wide by 450 feet deep, and almost all of it is being used for the project.
“They have nine trenches on the street side of the house,” he said. “If you don’t have that much yard … then they have to drill straight down, but that becomes a lot more expensive.
“We were lucky we had enough yard.”
The size of the geothermal field is determined by the size of the home; Robinson’s new house will be larger than 5,000 square feet.
Robinson said they decided to use geothermal units to heat water, as well, for the same reason.
“We’re heating water, basically, for free as opposed to having to use gas,” he said. “Where they bury the geothermal field, the ground temperature never changes at that point. The fluid they pump through that field … comes into the house the same constant temperature, and they use that to heat or cool the house based on the equipment that they’re using.”
Even though geothermal units have been around for about 40 years — Executive Heating & Cooling has been installing them for 30 years — awareness of the option is growing each year.
Granzow said the company has installed 3,000 geothermal units across metro Detroit, including a bank in Port Huron that was installed 30 years ago and a five-story building in Birmingham with a unit they put in 15 years ago. Fewer than a dozen companies do the work locally, he said.
St. Clair Shores Community Development and Inspections Director Chris Rayes said Robinson’s home is the only one he knows of in the city with geothermal heating and cooling.
Granzow said typical furnaces last, on average, 13-14 years. A geothermal unit lasts, on average, 28 years.
“That’s just on the indoor equipment,” he said. “The outdoor equipment, it’s (guaranteed) for 50 years.”
Installation for one geothermal unit can take about two-three days for the outside equipment and the same amount of time for the inside. In the Robinson house, four units were installed — one for each of the home’s two floors, one for the garage and one for hot water to fill an 80-gallon storage tank.
Getting one unit for each floor in that size home is more expensive but better in the long run, Granzow said.
Robinson is a general contractor and the owner of Black Star Construction, but he has never worked on a geothermal project before.
“It didn’t slow the project up at all because we were able to keep on working on other things at the same time,” he said. “We’re really happy to be able to build our dream home in St. Clair Shores.”
He said he and his wife have lived in the city for about eight years now and felt lucky to find a vacant lot on Lake St. Clair. Work began on the home almost a year ago and is expected to take another six months.
“We’re going to just get it done when it gets done and make it a pleasurable project,” Robinson said.
For more information about Executive Heating & Cooling Inc., call (586) 416-HEAT.