More asking Dahl’s Plumbing to set up geothermal systems
Jay Maze looks at the Earth as one big solar collector.
So when people call Dahl Plumbing asking about solar energy systems, he tells them about geothermal: using the stored heat in the ground for heating and cooling.
He must be winning some of them over. The company has 16 geothermal projects active; that compares to a rough estimate of 25 or 30 done over the four years Dahl has been providing that alternative. “A lot of them were big jobs,” Maze added in a recent interview.
Geothermal is still a small percentage of Dahl’s heating and cooling business — a small number in terms of total projects, but approaching 10 percent in dollar value, according to Mike Ortiz, assistant manager. “At this point, it’s a start-up for us,” he said.
The dollar value of the business is greater, because “it’s expensive — I make no bones about it,” Maze said. A geothermal system could cost from “the high 20s” to $40,000 when included in a newlyconstructed 2,000-square-foot home, he said. The cost is on the higher end of that range if the system is used for cooling as well as heating, while retrofits cost less.
The advantage, Maze said, is that homeowners could recover its cost over time in lower utility bills, and reduced ener- gy use will help the planet.
Just looking at heating costs, it would cost about $1,829 a year to heat that home with natural gas and $1,043 with a geothermal system, he said. The gap is significantly wider with propane, which could cost up to $7,400 for a heating season, he said. Maze said he thought that estimate might be high, but said he based it on the price a propane supplier gave him.
It’s not surprising, then, that a lot of the company’s retrofit work has been with homes and businesses, such as an old ranch in Wagon Mound, that rely on propane for heat. “We have some jobs in Eldorado, too,” said Jo Anne Peña, who assists Maze. “There’s a lot of propane (heating) out there.”
While many people think of bubbling hot springs or volcanic magma when they hear “geothermal,” this technology uses the normal stored heat in the earth in the way standard heat pumps have done for years. The technology sometimes has gotten a black eye, though, when it was badlydesigned or used in areas where the climate or geology did not make it practical, said Haze, who has worked at Dahl for 11 years as a mechanical contractor.
According to him, northern New Mexico is ideal for using geothermal in heating and cooling. Once you get below the top several feet of earth, the ground temperature here stays about 50 degrees Fahrenheit down to about 300 feet, he said. Geothermal uses that temperature to heat and cool homes, using phase shifts — the change of water from liquid to ice or to vapor — to increase energy efficiency, he said.
Here’s how it works.
The system uses a closed loop with lightweight but strong piping that is put down two separate drill holes about 200 feet into the ground. The piping also can be stretched horizontally in trenches dug below the frost layer, but Haze said that is disruptive to earth, and many people don’t have enough land for that. The drilling is a major element of the cost, though, often running about $10,000, he said, adding, “It’s faster and easier and tears up less ground.”
A slurry surrounds the piping so the hole doesn’t close up and allows flexibility so the pipe won’t break if the ground shifts. A water/antifreeze solution is pumped through the piping. In the winter, it can pick up heat from the ground, while it can discharge heat from the house into the ground in the summer.
Depending on which is needed, a compressor in the mechanical system can add heat to the solution, or a valve can vaporize it and make it colder. That mechanical equipment is bigger than a standard furnace and the compressor does make noise, so some people bury it and others isolate it in a mechanical room, Maze said.
It runs on electricity, but, by using the temperature changes available in the ground, the geothermal system produces more useful energy than it consumes, he said. It can work with either a forced-air or radiant heating system, but is more efficient with radiant heating. And it generally counts about 17 points toward a LEED (Leadership in Energy and Environmental Design) certification, he said.
The lifetime of the piping underground is estimated at 75 to 100 years, while the mechanical unit has about a 30-year lifetime, according to Maze.
“The larger custom homes have leaned in this direction,” Ortiz said, suggesting it might be a trend for the future.
Dahl Plumbing
WHAT: Offering geothermal heating and cooling systems
WHERE: 1000 Siler Park Lane
CALL: 471-1811
