What is geothermal heating?


Welcome to the second blog installation from Natale Builders. At the beginning of our last blog we gave a brief history of our business and the standards we keep in all of the homes we build. Green home builds are focused on energy efficiency, which eliminate the use of fossil fuels and substances that are harmful to the environment. Today we’ll explain the process of geothermal heating, a basic natural method that was first seen thousands of years ago by our cave-dwelling ancestors. Technology has given us the ability to use this sustainable technique on a commercial level, in our homes and buildings today.

What is Geothermal Heating?

Geothermal heating refers to the direct use of the earth’s internal heat to control temperatures in a home or building. It is sometimes confused with geothermal energy, which is a different process that actually describes the use of heat from the earth to generate electricity. Altogether, geothermal energy sources have gained popularity due to their cleanliness and sustainability.There are three main components that make up a geothermal HVAC system.

  1. The Ground Loop, which contains a heat transferring liquid.
  2. The Heat Pump unit, which enables the consistency of the heating and cooling as its distributed throughout a home or building.
  3. The Distribution System, which is responsible for carrying heated compressed air through ductwork, or heated water through pipes and radiators, depending on your system.

These green alternative systems differ from traditional HVAC systems because they do not burn fossil fuels to produce heat. Geothermal heating and cooling systems only use a minimal amount electricity to power the unit’s fan, compressor, and pump.How 

Does It Work?

Because we live on the earth’s surface, we experience great alterations in temperatures that constantly change with seasons. If we were to travel four to six feet below the surface we would find that the temperature stays pretty consistent. Geothermal systems are able to use these constant temperatures to produce energy. The system uses a network of high density pipes buried underground that transfer heat to and from the surrounding earth. This series of pipes is referred to as an open or closed earth loop that contains a liquid with agents to prevent it from freezing. Closed loops are generally used more commonly and can be installed either vertically or horizontally depending on property size; open loops are used if an aquifer is available in the surrounding area.

During the colder months of fall and winter, the liquid flowing through the loop absorbs the heat from the ground and is then taken through the system’s compressor that converts it to a higher temperature. Heated air is then dispersed throughout the home or building through the ductwork. In a closed hydronic system the heat is distributed through radiant pipes usually stationed in the floors. As the weather transitions into spring and summer the unit reverses the process, instead taking the heat from inside the home or building down the loop into a reinjection well that deposits the air to the cooler temperatures underground.

An open loop system is used to heat and cool a building when there is an ample source of groundwater available, such as from a well or pond. A pump is used to bring water into the home or building and through a heat exchanger in the system that is then carried through radiant pipes in the home. After the water has traveled through the system it is returned to the source by surface drainage or through a reinjection well. The only change that happens to the groundwater before it is returned is a slight temperature difference, keeping it completely harmless to the environment.

Efficiency & Cost

In the United States, the Department of Energy sets standards for COP (Coefficient of Performance) ratings, which measure the amount of energy a heating or cooling system uses. On average, geothermal systems receive a COP rating between 3.0 and 5.0. That means for every unit of energy used to power a system, 3 to 5 units of energy are put out. That efficiency can potentially cut a utility bill up to 70%. The cost of a geothermal system is based on per ton of heating and cooling capacity. They can range anywhere between $5,000 and $8,000 per ton. Installation depends on your property size and soil condition; the more drilling or digging that is required, expense will increase. For example, a 200 square foot home would need between 1500 and 1800 feet of pipe. Being able to install pipes horizontally is a smaller investment because they are easily buried in 4 foot trenches, but require a larger area of land. Smaller or rockier properties are more costly because the pipes have to be set vertically and require holes to be drilled around 300 feet down. Depending on your areas utility rates; as well as excavation costs, your home’s insulation quality, and system model, your payback period can be as brief as 7 or 8 years. Tax incentives tend to fall between 30 and 60 percent of the total cost. As new practices of installation are developed however, overall cost is starting to decrease.

Maintenance & Features

Geothermal heating and cooling systems are very easy to maintain, simply because they require very little upkeep which include basic evaluations, filter changes, and coil cleaning. Because units are stored indoors, they are protected from severe weather which keep the fan, compressor, and pump in good health for up to 10 years or more. Earth loops can last even longer being protected underground, staying operational for generations. In addition to heating, cooling, and quiet operating, geothermal HVAC systems can simultaneously handle the heating of pools and water used in the home. 

Technology continues to develop new and exciting ways to live healthier and more efficiently using natural energy from the earth. Discoveries that can outlive harmful processes of the past and put an end to wasteful utility costs. Thank you for choosing Natale Builders! Check back next month for new blogs!