In recent years heat pumps have become increasingly common in newly constructed homes or as an add-on to older homes, but how they work is a mystery to many. There are two types of heat pumps, those that use air and those that draw from a ground-source. Essentially, those that use air work to pull any available heat from the cold outdoors in the winter, then by using an electrical system it distributes that heat inside the house, essentially the inverse of how an air conditioning unit works in the summer. The heat pump is generally connected in to a forced air heating system to distribute the heat throughout the home. Air-source heat pumps are the more common of the two heat pumps, primarily because they are cheaper to purchase and easier to install, however the ground-source heat pump is by far the more efficient option.
Homeowners who are looking to live more sustainably or those that intend to remain in their home for a long period of time should consider the more expensive ground-source heat pump. As the name implies ground-source heat pumps get their heat from underground. Ground temperatures are more consistent than air temperatures allowing for a higher degree of efficiency for the heat pump. As previously stated a ground-source heat pump requires a more involved installation process and would generally only be completed by a certified HVAC professional. Depending on the terrain, either long trenches 3-6’ deep, or vertical boreholes, will need to be dug to lay the necessary “loop” of piping. Consumers also have the option with these systems of using groundwater to pass through the heat exchanger rather than refrigerant. That groundwater can then be returned to the aquifer. Setting this up would be part of the standard ground-source heat pump installation.
It may initially seem counter intuitive that using electricity with the heat pump will actually be any cheaper for the homeowner than just running a standard gas heating system, however because the electricity is only being used to move heat rather than to actually generate it there will be a savings. The heat pump definitely delivers more energy than it consumes. Because the ground temperature stays warmer than the air temperature in the winter, a ground-source (or geothermal) heat pump will be the highest level of efficiency.
A heat pump can then be reversed in the summer months to pull heat from the air inside the home and move it outside, thus further increasing its value. Most homeowners see an energy savings of 30-40% year round after installing a heat pump. It’s also interesting to note that the heat pumps sold today are more than 3x more efficient than those sold 30 years ago. So if you looked at heat pumps in the past but had trouble justifying the initial cost, it might be worth giving it another consideration.