Ask Our Experts: What is a Geothermal System?

In this series, our experts address some of the most common and helpful questions that we receive from customers and community members alike.  This month’s question focuses on when a geothermal system might be a good option for you.

Question for Our Experts: 

It seems like all the rage today in HVAC centers on geothermal systems.  What is a geothermal system anyway, and how might it benefit me?

Our Experts’ Answer:

The Short Answer

When installed properly and in the right context, geothermal systems are capable of providing superior operating efficiency versus traditional air source heat pump systems.  However, like any other home comfort system, geothermal systems come with their own unique pros and cons.  For example, it may be too costly to install a geothermal system at a home with an existing traditional system and ductwork.  Additionally, homes on very small plots of land may simply not have the space for geothermal to work in their situation.  Thus, it is important to seek professional expertise for help in choosing the right system for your home, we here at Tuckey Mechanical Services would be happy to discuss the options with you! Contact us!

The Detailed Answer

The specific details and inner workings of a geothermal home comfort system can get pretty complicated.  But we can provide some basic principles and considerations surrounding geothermal systems that should prove useful to you.  Of course, we highly encourage you to speak with trained professionals like those at the Tuckey Companies to help determine whether geothermal is the right option for your home or office.  That being said, here we go:

Just as a traditional air source heat pump gets its heat from the surrounding outside air, a geothermal heat pump gets its heat from the surrounding earth or ground using water as the transfer medium.  What makes the geothermal system more efficient is the fact that ground temperatures in our area (South Central PA) can range from just below freezing (32 degrees F) to about 70 to 80 degrees F while outside air temperatures in this area can range from 0 degrees to 100 degrees F (or perhaps even lower/higher if the winter or summer is particularly severe). Thus, an air source heat pump is not as efficient as a geothermal heat pump when the outside air temperature is at 5 degrees while the ground temperature is at 35 degrees. A geothermal system can extract more heat from the 35 degree ground, while the traditional air source heat pump is forced to extract heat from the 5 degree air outside.

There are two (2) types of geothermal systems generally recommended for residential installation.  They are referred to as open loop and closed loop. The open loop system draws groundwater from a supply well and discharges into the same well (as long as intake and discharge are far enough apart), or into a second well, or into a French-type drain back to the ground. The closed-loop system circulates water through buried piping (horizontal or vertical). Geothermal systems can be installed in most homes but will be limited to a certain ground area required for the loop system, in other words, geothermal systems require space. If your building is on a very small plot of land, a geothermal system might not work for you. Check with your local authorities as far as code compliance in regard to drilling or excavating.

As with any system, it is crucial that a heat loss/gain calculation be performed on the home before any equipment is selected (this is best done by trained professionals like those here at Tuckey Mechanical Services).  Due to their good dehumidification properties, geothermal systems can be sized very close to the actual heat loss of the home. This is not the case with a standard air source heat pump.  In other words, a properly-sized geothermal system will often fit your building better than a properly-sized traditional system will fit your building. We should note, however, that it is not recommended to size the geothermal equipment to match the heat loss of a home with an existing duct system, which probably would not be able to accommodate the larger equipment capacity. The bottom line here is that the best application for a geothermal system would be in new construction where the equipment and the duct system can be sized accordingly, not in an existing building.

A geothermal system is priced about 2 to 3 times more than an air source heat pump and though more efficient, may be prohibitive as far as an acceptable payback period is concerned. This would depend on many factors like the age of the home, insulation & infiltration factors, temperature settings, weather, and existing duct system vs. new.  This is another area where professional expertise is required in helping to make the right decision for your home.

Finally, it’s important to note that if geothermal is not an option in your home, air source heat pump technology has significantly improved over the past few years and may be able to provide you with the energy and cost savings you desire.  New-model, variable speed-type traditional equipment can often produce efficiency close to that of the geothermal heat pump.  Either way, our trained team members can assist you in selecting the right equipment (whether geothermal or traditional) for your home.

The Bottom Line

Like any other type of home comfort system, geothermal systems have their own unique pros and cons.  It is important to recognize that geothermal systems often work best when installed during new home construction, it may be too costly to install geothermal systems at homes with existing traditional systems and ductwork.  Additionally, geothermal systems may often involve 2 to 3 times the up-front cost associated with traditional systems.  However, in many cases geothermal systems offer significantly improved efficiency and operating cost effectiveness, making these systems an attractive option for many homeowners.

The experienced professionals at Tuckey Mechanical Services can install and service all types of systems from traditional boilers, furnaces, and air conditioners to modern ductless or geothermal systems.  We’d love to discuss your options with you, and help make the best decision for your scenario.  To get started, just give us a call at (717) 524-1136 or visit us online at www.tuckey.com!