Advice from a Geothermal Engineer


Today I had the opportunity to get lunch with Don Easson.  Don is a licensed Professional Engineer and the only IGSHPA (International Ground Source Heat Pump Association) certified geothermal designer in South Carolina.  In addition to owning and managing his residential geothermal design business, Don is also an independent distribution of ClimateMaster geothermal products. He works with Climatemaster, designs geothermal systems for homeowners, and is the person that existing geothermal owners sometimes call when their systems are not working properly due to design.

As you can imagine, with all of that experience in front of me I could not help but ask him a few questions that I could post here on the blog.  Between bites of food, I asked Don some questions about the issues he has seen homeowners face when purchasing geothermal systems, and what advice he normally offers to these individuals.

I started off by asking Don what he has found to be the most common geothermal design issue.  Right away, Don answered that the lack of a Manual J heatload calculation in the sizing of the geothermal system is the most common issue he comes across.  He informed me that contractors sometimes use “rule of thumb” measurements and estimates based on existing equipment to size the load of a home.  A Manual J calculation involves measuring many components and features of the home and thoroughly calculating the amount of heating and cooling needed in the rooms.  This is a key step in the geothermal design process.

“If you don’t do that, you’re at risk,” Don says about getting a Manual J calculation from your installing contractor.

He explained that an improperly sized system can cause a myriad of issues for a homeowner.  If a system is under-sized, it can cause the loop field to overheat and keep the system running far longer than necessary, increasing utility costs.  If a system is over-sized, it will cut on and off too often, known as short-cycling, and fail to remove the necessary humidity from the air in the rooms.  Both scenarios are far from ideal and defeat the purpose of purchasing geothermal as a high efficiency, luxury heating and cooling system.

Another question I asked Don was for the advice he gives to homeowners when they are offered various “accessory” products from HVAC contractors with their geothermal systems.  For homeowners reading this blog who own geothermal systems, you were probably offered or purchased several additional components with your geothermal system to improve its efficiency, air quality, or comfort level.  Because geothermal systems are high end systems, most homeowners can justify the cost of an additional accessory to add onto their geothermal system.  In many cases, these purchases are wise decisions and increase a homeowner’s satisfaction with the system, but sometimes it is hard to tell which accessories should be purchased and which should be left on the proposal.

In response to this, Don advised me to have homeowners consider the unique properties of their home.  If a contractor starts offering you accessories for your geothermal system without asking you about your home or considering its unique characteristics, you may want to step back and question if it is really necessary.

I appreciate Don taking the time to answer a few questions and hope you found this helpful!  If you have any advice to offer in geothermal designs, please feel free to comment on the blog below.  For helpful tips on choosing a geothermal contractor, see our post here.  To learn more about ClimateMaster’s geothermal equipment that Don offers, visit here.



Comments (1)


  1. ron weber says:

    Don Easson, PE

    I installed a geothermal open loop system, using a lake as the source and dump in 1978. The inlet is 12′ below pool.
    I live in Reston, VA.

    The minimum design temperature for in water is 40 degrees F. Since the water sometimes gets below 40, the water is pre-heated under these conditions by diverting it to a 40 gal hot water tank with 3 resistors (a 3kw, a 6kw and a 6kw). Each resistor can be manually turned on or off with its own toggle switch. (The unit originally came with a sensor and when the water dropped below design the unit would automatically add heat, but this did not work well so I went to manual operation. The only problem is that manual operation is time consuming and someone has to monitor the water temperature almost daily).

    This past winter the water never dropped below 40 so I never had to add heat to the water. (A plus for global warming!)

    I wish to replace the unit with an Infinity 5-ton unit and want to keep my preheat water tank. BUT I WANT THIS TO WORK AUTOMATICALLY! I have not seen such a unit in the literature but surely it is technically possible to build the circuitry, and at a reasonable cost. Can you help me in my quest?


    Ron Weber, PE

    PS When drought conditions exist I exhaust the water to my garden and trees. Saves me about $100/year over using city water.