Geo-thermal Energy

Installed Geo-Thermal System

After all the shell energy improvements have been made it is time to consider a vertical closed loop geothermal heating and cooling system added to your building energy cost reduction plan. The geothermal system can also qualify for rebates, tax credits, and energy improvement loans. The dollar savings can easily justify the investment. Vertical closed loop (grouted) systems are becoming the industry standard for geothermal system design. Its low operating cost, very low maintenance (no outside well pump system or casing), and no combustion flame lowers your homeowners insurance cost. Other geothermal systems have environmental risks and high long term maintenance cost and the risk is the homeowner responsibility. Other system failures are well pump replacements, heat exchanger failure allowing refrigerant and oil to enter the water well polluting the drinking water aquifer. The closed loop system safe guards the water aquifer. No water is used or returned to the aquifer. Several open systems (called pump and dumps) have been shut down in Maine and elsewhere. For details, call the environmental protection agency on which system is preferred to protect the environment, pump and dump, open loop or vertical grouted closed loop.

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Geothermal Systems

Geothermal heating systems harness heat stored in the earth and transfer it between the earth and your home using a heat pump. Though the air temperature changes drastically from season to season, the temperature of the earth just below the surface is far more consistent and falls generally between 48 to 50 degrees Fahrenheit. In the winter your heat pump pulls heat out of the earth to heat your home. In the summer, your heat pump puts heat back into the earth to cool your home.

Geothermal heating systems are among the most efficient heating and cooling technologies, and though they tend to be relatively expensive upfront, the energy savings are tremendous. Additionally, maintenance is usually minimal because of the simplicity of design. With the 30% federal tax credit, incentives through Efficiency Maine, and utility and state rebates available, there's never been a better time to modernize your home with a geothermal system.

Click here to see an example of a geothermal-solar hybrid solution

Current Projects


We recently completed work on a one story ranch in North Dexter. Our client approached us wanting to switch from oil to an alternative heating system. He wanted to remove his oil-fired furnace and install a hybrid geo-solar hot water heating system.

Energy Savings and Auditing performed an energy audit including a blower door test to size the heating system. Based on the audit, we determined our client needed a three ton closed loop geo-system. We were aiming for a coefficient of performance (COP) of 4 for his home, and decided to add a solar hot water system to the geothermal system. ESA's partner Pine State Drilling installed the geo-field, heat pump, and solar panel. ESA installed a cooling system using direct water flow from the geo-field to cool the house in the summer. The energy performance of the system turned out better than we hoped—a COP of 4.2! With the addition of the solar gain, we lifted the COP to 6.97!

Another project, a two story home on full foundation in Waterville, had an existing four ton geothermal system which was failing to heat the house adequately. The original COP scored a low 2.4, and the owner had even returned to heating his home with oil because the geothermal was performing so poorly. To learn more about this project click here.

Checking a door for leaks using Infrared

Our energy audit and blower door test identified a number of problems with the geothermal system and the building envelope. To see this example click here. We determined that the geo-field was too small in size, the piping to the heat pump was undersized, the heat distribution system into the house was incorrectly plumbed, and the pumping system and pipe sizing were also under-designed for the distribution needs of the building. Again, our partner Pine State Drilling assisted us by adding a four hundred foot bore hole to the two three hundred foot bore holes. ESA increased the piping between the bore hole and heat pump, and completely redesigned the piping and the pump arrangement of the house's heating distribution. Our modifications yielded a COP of 4.0, and the heat pump desuperheater now recovers waste heat to heat all the domestic hot water. The oil boiler is turned off. The blower door test showed a very high air infiltration reading of 5,800 cubic feet per minute (CFM-50), which indicates major air infiltration into the building. To remedy this, the owner completed some masonry work on the foundation and applied foam insulation in the foundation, floors, and roof to secure his home more tightly. The modified four ton geo-system now properly heats his house.

To see equipment for geo-thermal drilling click here

To see some common insulation problems click here


A lumber mill in New Hampshire wanted an energy audit to assess electricity and steam usage and a feasibility study to change from oil heating to wood heating and lower their utility rates. We divided the energy audit into two parts: electrical use and oil use on an annual basis. The electrical usage audit found a power factor penalty surcharge which we corrected by installing capacitors. The oil use audit indicated the ideal size of the wood fire boiler and the necessary magnitude of the steam heat load required to heat their kilns and buildings. The audit data indicated that a four hundred horsepower boiler running a sixty kilowatt back pressure turbine would be needed. This system allows heat transfer to buildings and kilns and lowered the overall operating costs by 50%. The system relies on cogeneration, the simultaneous production of electricity and useful heat and runs off of waste wood. EAS corrected the power factor penalty which saved the lumber mill even more on utility costs.

man checking central AC unit.

Energy Auditing

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Heating System Optimization

Boilers, furnaces, radiant floor, duct work, base board, zoning, domestic hot water heaters, heat pumps, air conditioners, and lighting are parts...
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Geothermal Energy

The future of Maine Heating systems will be Geothermal heating. The most environmentally friendly system is a vertical closed loop system.