The right choice for you?

Many Vermonters are wondering if a ground source heat pump (GSHP) would lower their energy costs. A GSHP system requires a large initial investment, so it makes good economic sense to determine whether this technology will be cost-effective for your specific needs. This page will help you identify important points to consider as you evaluate your options.

A GSHP system uses electricity to pump heat to and from the ground to heat and cool a building. The ground acts as either a heat source for heating or a heat sink for cooling. The system includes an electric water pump, to pump the water used to transfer heat to and from the ground, and a type of compressor called a heat pump. To provide heating, the heat pump extracts and concentrates heat from the incoming water and transfers it to a building's heat-distribution system (forced air or water) and/or water-heating system. To provide cooling, the heat pump transfers heat from a building's air to water that is then pumped back underground.

Most installations use open-loop systems, in which groundwater is pumped from a drilled well through a heat pump, which transfers heat into the building, and then most of the water is pumped back to the well. Closed-loop systems circulate a heat-transfer fluid through coils of buried tubing to move heat either to or from the ground.

Choosing a system appropriate for the physical characteristics of your property and for your budget requires the design expertise of a GSHP contractor, along with the advice of an unbiased energy professional. For commercial buildings, this energy professional would be a mechanical engineer who is familiar with GSHP technology and alternatives. For residential buildings, speak with a certified Home Performance with ENERGY STAR® contractor.

Typically, GSHP systems installed in Vermont commercial buildings are designed to provide both heating and cooling. The cost effectiveness of a GSHP system is likely to be greater when it's installed at the time of building construction, rather than as a replacement system, and when the building has large heating and air-conditioning needs. However, it may also be cost effective, in some circumstances, to replace existing commercial heating and cooling systems with GSHP systems.

Most GSHP systems for homes in Vermont are designed to supply space heat and, less often, to provide air- conditioning and/or supplement water heating. For homes with smaller heating needs that also require little or no air conditioning, the cost effectiveness of a GSHP is more limited. Also, it's more cost- effective to place a GSHP system in a new home than in an existing home because installation costs are lower at the time of new construction.

Regardless of the kind of heating/cooling system you use, keep in mind that the first steps toward reducing heating and cooling costs are to minimize air leakage and to optimize the insulation levels of a building. This is particularly important with GSHP systems. That's because the cost of buying and installing a larger-capacity GSHP system is typically far greater than the cost of reducing a building's heating and cooling needs through energy efficiency.

For a list of energy professionals serving residential customers, go to the Residential Marketplace and select Home Performance with ENERGY STAR Contractor or call, toll-free, 888-921-5990.

For a list of energy professionals serving commercial customers, go to the Business Marketplace and select Geothermal Evaluation Resource or call, toll-free, 888-921-5990.

Although GSHP equipment may be rated as efficient, the actual overall operating efficiency of a system will be lower than the rated equipment efficiency because of the amount of electricity required by the system's pumps. System efficiency may be further reduced by flaws in design and/or installation. The extent of efficiency losses varies from one installation to another, but losses can be significant.
The efficiency of GSHP equipment, in heating mode, is indicated by its coefficient of performance (COP), which is the amount of heat provided per unit of energy used. The efficiency of the equipment in cooling mode is indicated by the Energy Efficiency Ratio (EER), which is the amount of heat removed per unit of energy consumed. ENERGY STAR qualified heating and cooling equipment installed as part of a GSHP system must meet or exceed the efficiency standards outlined in the table below:

• A well-designed and correctly installed GSHP system can be an efficient way to use electricity to heat and cool some buildings, such as larger buildings with substantial air-conditioning loads.
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• When used for heating, GSHP systems can emit as much as 15% less carbon dioxide than is emitted by other fossil-fuel heating systems. Even greater emission reductions can be achieved when the electricity to power GSHP equipment comes from renewable sources, such as solar or wind.
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• The potential for a GSHP system to reduce heating and cooling costs from those of conventional heating and cooling systems generally increases as energy prices increase.
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• GSHP systems are significantly more expensive to purchase and install than conventional heating and cooling systems. The cost to purchase and install a residential GSHP system can range from $10,000 to $30,000 more than the cost of a conventional system. It is difficult to estimate a comparable range of costs for commercial applications because each situation is site-specific.
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• GSHP systems that distribute heat through baseboard convectors or radiators generally will not perform well. This is because GSHP systems produce relatively low-temperature hot water. However, GSHP systems typically work well with low- temperature heat-distribution systems like radiant floor heating systems and forced  air systems.
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• Some existing water wells don't have enough supply to meet the needs of an open-loop GSHP system. In these situations, a new well, pumping equipment, and possibly water treatment equipment may need to be purchased. Drilling through difficult soils and rock can increase initial investment costs.
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• Some residential GSHP systems deliver most but not all of a home's heating needs. Homes with such systems require supplemental heat during the coldest periods of winter. All supplemental heating equipment and operating costs should be considered when determining whether a GSHP system will be a cost-effective investment. An economic analysis worksheet is available to assist you in determining whether a GSHP system could be cost-effective in your building.

The GSHP industry is relatively new to Vermont. Currently, purchase and installation costs vary considerably from supplier to supplier and installer to installer. Also, only anecdotal data exists regarding the performance and operating costs of systems installed in Vermont. This makes it difficult to accurately compare vendors' cost projections with Vermonters' actual experiences. Whether in a commercial or residential application, it's advisable to exercise care in choosing equipment vendors and installation contractors. Efficiency Vermont recommends obtaining an independent assessment of savings estimates, which can be provided by an energy professional who is familiar with GSHP technology and alternatives. Before investing in a GSHP system, it's a good idea to balance purchase, installation, maintenance, and fuel costs against potential energy savings to determine whether you'll see a return on your investment. An economic analysis worksheet is available to assist you in determining whether a GSHP system could be cost-effective in your building.

Step 1: The most important step is to work with an independent and objective energy professional. These experts can assess the efficiency of your building and calculate its heating and cooling needs. They also can inform you about cost-effective improvements you can make to reduce heating and cooling needs before investing in a new GSHP system.

For a list of energy professionals serving residential customers, go to the Residential Marketplace and select Home Performance with ENERGY STAR Contractor or call, toll-free, 888-921-5990.

For a list of energy professionals serving commercial customers, go to the Business Marketplace and select Geothermal Evaluation Resource or call, toll-free, 888-921-5990.

Please note: Efficiency Vermont does not endorse any particular partner in promoting this service. Efficiency Vermont neither expressly nor implicitly warrants the performance of any partner. Contact your contractor or supplier for details regarding equipment warranties.

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Step 2: Contact a firm specializing in GSHP equipment and its installation. Ask for an estimated cost to purchase, install, and maintain the system.

For a list of firms, please visit:

International Ground Source Heat Pump Association Business Directory

Renewable Energy Vermont Business Listing

Please note: Efficiency Vermont does not endorse any particular partner in promoting this service. Efficiency Vermont neither expressly nor implicitly warrants the performance of any partner. Contact your contractor or supplier for details regarding equipment warranties.

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Step 3: Work with your energy professional to compare your current heating and cooling energy costs with those incurred with a GSHP. For a commercial building, also ask for a life-cycle cost analysis.

To help compare costs, a fuel-cost calculator and a GSHP economic analysis worksheet are available:

Fuel Calculator

GSHP Economic Analysis Worksheet

To find available tax credits & incentives please visit:
EnergyStar.gov
DSIREUSA.org

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Step 4: Contact Efficiency Vermont for information about how to evaluate a GSHP system for your application. We're here to help you find answers to your questions, so that you can decide whether a ground source heat pump is a cost-effective system for your needs. Call, toll-free, 888-921-5990.