Ground-source heat pumps can be paired with either forced hot air or hydronic distribution systems to distribute heating or cooling throughout the home. With forced hot air distribution, the heat pump transfers heat to air that circulates through ductwork. With hydronic heating distribution, the heat pump transfers the heat to water that is circulated to baseboards or radiators. One reason ground-source heat pump systems are so efficient is that they deliver water at modest temperatures, approximately 110 to 120 degrees Fahrenheit, but this usually requires longer baseboards or larger radiators than those designed to work with traditional boilers. However, the old baseboards or radiators can often be replaced by heat pump-compatible ones in the same locations.

Ground-source heat pump systems are compatible with zoning your house for heating and cooling. Depending on the size of a home, multiple heat pump units may be used to heat sections of a house (such as an entire floor, or all of the bedrooms).

Ground-source heat pump configurations

The ground loops for ground-source heat pump systems can be installed in different configurations, depending on the amount of land available and whether there is a well or a pond next to a home.

The most common system type in Massachusetts is a closed-loop vertical system. The system circulates an antifreeze mixture through pipes that extend around 500 feet into the ground within one or more boreholes that are at least 20 feet apart from each other. The second most common type of ground-source heat pump in Massachusetts is an open-loop system. This system exchanges water directly with an underground well or a pond. Groundwater is returned to the pond or well after passing through the heat pump.

Another ground-source heat pump configuration that is less common in Massachusetts due to space requirements is called a closed-loop horizontal system. Similar to the closed-loop vertical system, an anti-freeze solution is circulated through pipes that are laid out horizontally at a depth of about six or more feet underground. Horizontal loop systems require more yard space than vertical loop systems, but they can cost less to install if the digging conditions are favorable. However, closed-loop horizontal systems can be less efficient than vertical systems, due to the greater ground temperature fluctuations at shallower depths.

Home improvement scenarios that work with ground-source heat pumps:

  • Existing home replacing heating or cooling system
  • Existing home doing major renovations
  • New home construction using ductwork or baseboard heaters

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