Geothermal Heating and Cooling

Renewable HVAC

Geothermal Heating & Cooling (GHC) systems can use thermal energy stored under the Earth’s surface anywhere in Maryland to heat and cool homes with renewable thermal energy generated from fission at the center of the Earth and solar gain during the summer. This stored thermal energy can be converted to heating and cooling for homes and businesses using drilled wells, piping loops, and efficient heat pumps that transfer heat between the wells and the home or business.
• In the winter, the GHC system pulls heat from the earth into the house or building;
• In the summer, the system removes heat from the house or building by dumping it into the ground; and
• Year-round, they can heat water with a desuperheater—a secondary heat exchanger that transfers heat from the earth in the winter, and from your home in the summer, into your domestic hot water tank.

GHC systems are the most energy-efficient, environmentally clean, and cost-effective space conditioning systems available, according to the Environmental Protection Agency.1 EPA found that GHC systems can reduce energy consumption by over 40% compared to air source heat pumps, and by over 70% compared to electric resistance heating with standard air-conditioning equipment. EPA also found that GHC systems are 48% more efficient than the best gas furnaces on a source fuel basis, and over 75% more efficient than oil furnaces.

Renewable Energy Credits (RECs)

HB 1186 (May 22, 2012) allowed Maryland to become the first state in the country to make the energy generated by GHC technologies eligible for the Renewable Portfolio Standard (RPS) as a Tier 1 renewable source.  GHC system owners are also eligible for Renewable Energy Credits (RECs), equivalent to 1 MegaWatt-hour (MWh) of electricity. 

To qualify for RECs, the GHC technologies must:

  • Meet ENERGY STAR standards (see Geothermal Heat Pumps Key Product Criteria website for more information),
  • Displace electric or non-natural gas (NG) fossil fuel heating systems
    • 29% of homes in the Mid-Atlantic region use electric/non-NG fossil fuel heating
    • 46% of businesses in the Mid-Atlantic region use electric/non-NG fossil fuel heating
  • Displace old and presumed inefficient air conditioning systems
    • 44% of homes in the Mid-Atlantic region have AC units 10 years+ old
    • 74% of businesses in the Mid-Atlantic region have AC units 10+ years old

The following steps will help you turn your GHC RECs into a new revenue stream:

  • Register for RECs
    • Fill out the GHC REC application posted on the Public Service Commission website as an Excel spreadsheet.
        • For residential systems, the PSC will use the calculator posted on MEA’s website to estimate RECs.
        • For commercial systems, you’ll need to enter the projected MWh’s from your installer’s engineering studies onto the REC application spreadsheet
    • Send the completed spreadsheet to
    • Print, sign and file the GHG REC application with the Public Service Commission. Instructions to file are included on the GHG REC application. Please note that original plus 17 paper copies are required. All requested documents are listed on the Instructions page of the GHG REC application. Send all material to:

      David J. Collins

      Executive Secretary

      Maryland Public Service Commission

      6 Saint Paul St.

      Baltimore, MD 21202

  • Sell your RECs
    • Information about selling RECs can be found here, which includes information that includes:
      • How the REC owner can advertise his credits on the GATS Bulletin Board or check-out the Buyer’s Bulletin Board for specific purchase requests.
      • How the REC owner can use an aggregator or broker to either purchase the RECs directly, or to assist the REC owner in finding a buyer.
      • Finally, the REC owner could use an auction or exchange platform to sell RECs.
    • Sustainability Frameworks

GHC can be a major contributor to sustainability goals set by established “green building” standards such as the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED), Net Zero Energy Homes and Buildings, and the Living Building Challenge. 

One elementary school in Richardville, Kentucky leveraged green design with solar PV and GHC to become the nation’s first Net Zero Energy School, which means that the school generates more energy than it consumes over the course of a year.   

Apply for a Geothermal Heat Pump Grant


Contact Clean Energy Program Manager Marta Tomic via email at or telephone 410-260-2608.