Can Geothermal Heat Your Home?

(Photo: Cristiano Galbiati)

The term geothermal refers to heat within the earth. This heat can present in dynamic, forceful phenomenon like the geysers of Yellowstone or simply as a constant reserve of energy. The latter, the low-grade heat near the earth’s surface, is an efficient, clean and cost-effective energy that can be used to heat, and cool, your home.

The principle behind geothermal energy use is simple. In winter, the ground is warmer than the air and in summer the inverse is true. Capturing the latent energy in shallow ground (100-400ft) simply requires using a geo-exchange or ground source heat pump (GSHP) to circulate the thermal energy.

GSHPs are similar to traditional heat pumps. They are a type of air conditioning machine / refrigeration machine that can also be used in reverse. GSHPs use the earth as both a heat source and a heat sink. In winter, they draw thermal energy from the ground into your home for heating. In summer they transfer thermal energy out of your home and “sink” it into the ground or a body of water like a nearby pond.

Transfer of heat always requires a medium. With GSHPs, the medium is a fluid – either water or an antifreeze liquid. Using a small amount of electricity, the GSHP moves the fluid through looping that is placed in the ground or within ground water wells. The fluid transfers heat from hot to cold in accordance with seasonal preferences.

The implementation of this simple technology has exponential benefits to both the environment and the cost of running your home. Although they require a larger upfront investment, geo-exchange systems typically have operating costs 30-50% less than conventional HVAC systems.

Over the expected lifetime of the system components (which can be 30+ years), those savings add up. The simple design also offers the benefit of heating and cooling in one unit, eliminating the need to purchase both a furnace and an air conditioning unit. And, unlike conventional HVAC systems, geo-exchange systems are expandable meaning should you decide to add square footage to your home you don’t need to purchase complete new HVAC to size.

The environmental impact of geo-exchange systems is incredibly low. In fact, the Environmental Protection Agency endorses GSHP systems as the most “energy-efficient, environmentally clean, and cost-effective, active, space conditioning systems available.”[1] The EPA’s kudos is well deserved.

Geo-exchange systems use a renewable, non-polluting heat source. They are extremely energy efficient producing an average three heat energy units for every one unit of electricity – efficiency that outperforms natural gas furnaces by 40% and oil furnaces by 70% or more.

With all that free, clean energy why isn’t geothermal the standard energy choice for heating and cooling? Likely this is due to higher initial costs. While a GSHP is comparable in cost to conventional systems, the loop systems add to the upfront price tag. The cost varies with the type of loop system you choose but typically don’t start under five figures.

However, geo-exchange systems are cost-effective and can pay back within five years. The other bonus is perennial savings on utility costs. On average, homeowners can expect system lifespan savings around $20,000. The choice: pay upfront for a clean, renewable, efficient heating and cooling system or pay as you go for an inefficient system that is fed by foreign oil dependency.

One more savings homeowners recoup with geo-exchange – you don’t have to spring for a CO2 monitor.

*Note: The information in this article is general advice and not meant as a substitute for personal guidance from a financial advisor, real estate professional, general contractor or legal counsel. Although the author is a licensed realtor, the advice given in this article does not constitute any client contract or agreement between the author and the user. The author is not responsible for any losses, damages or claims that may result from your decisions.