Picking Heat Pumps: Air Source vs. Ground Source

Heat pumps warm your home in winter without consuming natural gas or utilizing electric heating. In the summer, the same unit cools your house like conventional A/C. In addition to consolidating heating and cooling into a single, efficient unit, heat pumps can substantially cut monthly utility bills. Since no combustion is involved in the heating process, a heat pump also reduces your contribution to greenhouse gases.

Heat pumps derive heat energy to warm your home from two sources: the air and the ground. Here’s how the methods differ.

Air Source

Even in frigid winter conditions, outdoor air contains some latent heat energy. In heating mode, an air-source heat pump extracts latent heat from the air outside, then concentrates the heat energy with the system compressor to generate sufficient warmth to heat the house. In cooling mode, the heat pump functions like a central air conditioner, extracting heat from inside the house and dispersing it into outdoor air.

Today, high-efficiency air source units can extract latent heat to warm the house even when outdoor temperatures are well below freezing. Less efficient models, however, may require a supplemental heat option during periods of very low temperatures (rare here in Orlando.)

Ground Source

Less than 20 feet below the surface, the temperature of the earth remains around 50 degrees year-round. This provides geothermal heat energy for ground-source heat pumps. Loops of tubing circulating heat-absorbing fluid are buried in a horizontal grid or vertically in deep wells. Heat absorbed from the ground is pumped to the indoor compressor and concentrated to warm the house. In cooling mode, heat extracted from the home is absorbed by the fluid, then circulated through the underground heat exchanger and dispersed into the earth.

Ground source units can reduce heating costs by up to 60%. However, they require sufficient outdoor space to accommodate the buried heat exchanger. Local geology including soil type also affects installation costs as well as system efficiency.

For more about the benefits of both air source and ground source heat pumps, contact Rinaldi’s Energy Solutions.

Our goal is to help educate our customers in Orlando, Florida and surrounding areas about energy and home comfort issues (specific to HVAC systems).