For years, conventional wisdom among installers has been that a geothermal system requires an alternate or backup heating source, such as fuel oil or electricity. Such back-up is needed because geothermal systems cannot generate sufficient heat when temperatures become extremely cold.
But at least one installer is disputing the conventional wisdom.
A geothermal heat pump can provide the needed heating, even in the cold of a New England winter if the equipment is sized properly,” said Terry Queenan, founder of EarthTech Systems in Lowell, Mass. ‘It’s all based on load. The key is to do a heat loss/heat gain calculation known as a ‘Manual J’ calculation. If that is done correctly you do not need a backup.”
As a case in point, Queenan cited a recent project at a newly constructed 3,900-square-foot house in Westford, Mass. A closed-loop geothermal system that EarthTech Systems installed there has an output capacity of 29,000 British thermal units.
The house has a 10KW electric ‘heat pac” for backup, but the owners did not have to turn it on once this past winter. ‘Even at minus eleven in January they didn’t have to turn on the electric,” Queenan said.
With the geothermal unit running close to five hundred hours a month this past winter, the house in Westford cost about $160 a month to heat ‘ working out to 32 cents per hour. ‘All the components are engineered to be very energy efficient,” Queenan said. That includes two-stage compressors, electronically commutated motors and non-pressurized flow centers.
The energy consumption of the Westford house is being monitored and can be followed online through the EarthTech Systems website (earthtechsystems.com). The data collection and presentation is being handled with technology provided by Ground Energy Support (groundenergysupport.com), based in Dover, N.H. Ground Energy Support markets its GxTracker system to geothermal installers and users. It provides residential and light commercial ground source heat pump users with a monitoring and verification system that shows real-time data about the heat transfer, environmental and cost benefits associated with their GSHP heating and cooling system. Installers can see the ‘health” status of their installations and can link directly to the energy dashboards where operation metrics and data are shown.
Geothermal heating and cooling utilizes the constant temperature of the Earth to heat a dwelling during the winter months; similarly, heat is removed from the dwelling and deposited back underground during the cooling season. This is accomplished through the use of a geothermal unit installed in the dwelling and a high-density polyethylene pipe buried in the ground. Together, these two components use the earth as a year-round heat exchanger.
Queenan, a 40-year veteran of the fuel oil industry, mostly as an installer and service technician, ventured into installation of geothermal heat pumps about ten years ago. ‘Our geothermal business has probably grown about 50% in the past four or five years,” he said. The company installed about twelve systems in 2013.
In contrast to installation of an oil-fired unit, ‘They’re time-consuming,” Queenan said of the geothermal systems. ‘They can take weeks to do.” And there is one aspect ‘ the drilling of bore holes for wells ‘ where outside expertise is required.
EarthTech Systems works with a well-driller, Skillings & Sons, Amherst, N.H. Drilling can take one to two weeks and the system installation can take another week, or longer, Queenan said. ‘They’re very heavy cumbersome machines,” he said of the heat pumps, weighing from 400 to 800 lbs.
Queenan also noted that his lead installer, William Dowling, is a seasoned plumber who has a vast knowledge of heating and air conditioning. ‘That makes it a little bit easier,” he stated.
The lion’s share of installations that EarthTech performs consists of closed-loop systems. For example, EarthTech recently completed an installation for a 3,500-square-foot house in Carlisle, Mass. The six-ton, non-pressurized closed-loop geothermal system provides 72,000 Btus for heating, cooling, and approximately half to three-quarters of yearly domestic hot water needs.
‘We needed a little over six tons ‘ at 12,000 Btus per ton ‘ to heat this house,” Queenan said. That meant drilling three 400-foot bore holes, which is slightly deeper than usual. Asked how much the installation cost the homeowner, Queenan said, ‘Because of the size of the job and the details ‘ the heat pump had to be installed in a closet ‘ it wasn’t an easy install. The price was in excess of $50,000″
Geothermal systems can start at about $20,000 and can go much higher, depending on a raft of variables including the size and condition of the house and especially how well or how poorly it is insulated.
As for who is buying geothermal systems, Queenan said the calls he receives tend to be from people who are tired of paying out large sums every winter to heat their homes. Most of the calls he gets are from homeowners with annual heating bills of $5,000 to as much as $14,000.
For example, Queenan has fielded a call from the owners of a 150-year-old house, who this winter paid an average of $3,000 per month for electric heat. That house would need five geothermal systems (i.e., 15 tons or 180,000 Btus), he estimated.
Then there is the odd, even more extreme case, such as the owner of a 10,000-square-foot house, now talking with EarthTech Systems, who has an annual fuel oil bill that is expected to top out at $40,000.
Typically a heat pump is installed in the basement. In some cases, however, EarthTech has installed ‘split systems” ‘ one part in the basement, one part in the attic. The company has also installed the units in crawl spaces. And, last year EarthTech installed two geothermal heat pump systems in the William Haskell house, a historic colonial in Gloucester, Mass., that, according to a website maintained by the Haskell family, dates from 1700 or earlier and is listed on the National Register of Historic Places.
Generally, houses of older construction present more challenges.
‘One of the big problems we see is leaky duct work stemming from improper sealing and insulation,” Queenan said. The company performs indirect sealing in such cases. He cited the house in Carlisle, Mass., as typical. EarthTech sealed the duct work and, based on tests conducted before and after, reduced leakage by 87%.
Though geothermal systems represent a sizeable investment, customers opt for them for a simple reason: over the long term they can provide savings on energy costs, according to Queenan and government literature available online. A geothermal system can reduce a homeowner’s total energy bill by roughly 50% to 70%.
‘A lot of these people just want to get off of fuel oil because of the cost,” Queenan said. ‘The market for the systems isn’t confined to the affluent. I’ve done them for mainstream people and I’ve done them for people who just have large homes and their energy costs are out of line.” Probably the most common statement he hears from prospective customers is: ‘My oil bill is higher than my property taxes.”
Many callers also are looking to cut their carbon footprint, he added. Supporting that, there is also available a 30% federal tax credit on geothermal installations.