Geothermal

Why Geothermal Heating and Cooling?
How Do Geothermal Heating and Cooling Systems Work?
Will Geothermal Work Well at My Home?
How Much Do Geothermal Heating and Cooling Systems Cost?
What Will I Save on My Heating and Cooling Bills?
Are There Incentives and Financing Opportunities?
Where Can I Find a Geothermal Contractor?

Why Geothermal Heating and Cooling?

The most readily developed source of geothermal energy in Maryland is the geothermal heat pump. Also known as the ground source heat pump, it is a highly efficient renewable energy technology, using 25%–50% less electricity than a conventional heating or cooling system. Geothermal heat pumps can reduce energy consumption—and corresponding emissions—up to 44% compared to air-source heat pumps and up to 72% compared to electric heating with standard air-conditioning equipment.

Geothermal systems also can provide water heating for household use or even your pool or spa. Excess heat from the geothermal heat pump's compressor can be transferred to the house's hot water tank, even operating when the heating and cooling systems are turned off.

Additional benefits of the geothermal heat pump include:

Humidity control—maintaining about 50% relative indoor humidity;
Space-efficient and easy installation—in new or retrofit situations, the hardware requires less space than conventional HVAC systems;
Flexible—“zone” space conditioning allows you to set different temperatures for the different areas of your home;
Long life—relatively few moving parts which are durable and highly reliable, with systems often lasting 20 years or more and warranties of 25-50 years for the underground piping.
Quiet—with no outside condensing units and no fans so there are no blasts of cold or hot air.

Increased demand for geothermal systems will create new jobs for Maryland. Geothermal installations require professionals to help design and install the system, as well as contractors who can do the labor required to install the loops and the pump equipment. It can also create new business opportunities for HVAC companies.

How Do Geothermal Heating and Cooling Systems Work?

The geothermal heat pump takes advantage of the constant temperature of the ground – cooler than the air above it in summer, warmer in winter—by transferring heat stored in the Earth or in ground water into a building during the winter, and transferring it out of the building and back into the ground during the summer. The ground, in other words, acts as a heat source in winter and a heat sink in summer.

It is important to note that geothermal heat pumps are different from air-source heat pumps. Air-source heat pumps transfer heat to or from the outside air while geothermal, or ground-source heat pumps, exchange heat with the ground. This is much more energy-efficient because underground temperatures are more stable than air temperatures through the year.

A geothermal heat pump system includes three principal components:

Earth Connection: Using the Earth as a heat source/sink, a series of pipes, commonly called a "loop," is buried in the ground near the building. It circulates a fluid (water, or a mixture of water and antifreeze) that absorbs heat from or radiates heat to the surrounding soil, depending on whether the ambient air is colder or warmer than the soil.
Heat Pump Subsystem: For heating, a geothermal heat pump removes the heat from the fluid in the Earth connection, concentrates it, and then transfers it to the building. For cooling, the process is reversed.
Heat Distribution Subsystem: Conventional ductwork is generally used to distribute heated or cooled air from the geothermal heat pump throughout the building.

Will Geothermal Work Well for My Home?

Geothermal heat pump systems are viable in just about any location in the state and can provide a consistent, reliable, and largely clean source of energy for residents.

Geothermal heat pump systems are not do-it-yourself projects. To ensure good results, the piping should be installed by accredited professionals. Designing the system also calls for professional expertise: the length of the loop depends upon a number of factors, including:

Whether you use vertical or horizontal loops;
Your home's heating and air conditioning load;
Local soil conditions and landscaping;
The severity of your climate.

Depending on the site, the geothermal loops can be installed vertically, sinking down into the ground, or horizontally, laid out flat beneath the surface of the ground. In either case, homeowners may need to rip out existing landscape to accommodate the system.

Larger homes requiring more heating or air conditioning generally need larger loops than smaller homes.

How Much Do Geothermal Heating and Cooling Systems Cost To Install?

Geothermal systems cost more than traditional HVAC systems – sometimes twice as much for a comparable unit. Add to that the cost of installing the geothermal loops, and the cost of a full system runs tens of thousands of dollars. But don’t get sticker shock! Many cities and counties in Maryland offer low or no interest loans and property tax incentives for the purchase of geothermal heat pump systems. Rebates, tax credits, and exemptions are available from the Federal and state governments too. See the MCEC Residential Financial Incentives page for more details.

How Much Will I Save on My Heating and Cooling Bills?

The U.S. Environmental Protection Agency estimates that geothermal heat pumps can lower energy bills by 30-40%. Most geothermal heat pumps systems recoup their costs in savings within 5 to 10 years.

Incentives and Financial Opportunities

Federal

The Federal government is offering the Investment Tax Credit—a 30% credit against income taxes due to the IRS.

State

Rebates of up to $3,000 for residential heat pump systems can be applied for through Maryland’s Geothermal Heat Pump Grant Program.

Local

Many local jurisdictions offer exemptions and credits on personal property taxes that can offset the cost of installing geothermal heat pump systems. For an expansive list of programs from the federal, state and local governments, go to the MCEC Residential Financial Incentives page.

Additional resources for the latest in financial incentives can be found at the Maryland Energy Administration’s Incentives & Resources page and the Database of State Incentives for Renewables and Efficiency.

Finding a Geothermal Contractor

It is important that you work with an accredited and experienced geothermal contractor who first can conduct a thorough analysis of your residential site. Designing the system also calls for professional expertise. Questions to ask when looking for a geothermal contractor include:

Are they licensed as a Maryland Home Improvement Contractor, electrician, HVAC, or plumbing contractor?
Does the contractor offer energy audit services or will you need another contractor?
What kind of site analysis and consultation services does the contractor offer prior to installation?
How many installations have they done over the lifetime of the company and in the last year?
What kind of certifications does their staff hold? Is someone on the staff certified by the North American Board of Certified Energy Practitioners (NABCEP)?
How will they help you with incentive and grant funding applications?
Does the contractor only install the system or do they also provide maintenance?
Are they a national organization or local to the state?

Use the MCEC resource directory to identify Maryland companies who specialize in geothermal heat pump installations.

The International Ground Source Heat Pump Association and the Geothermal Exchange Organization also have directories of accredited geothermal heat pump professionals.