Geothermal and Solar – Becoming Net Zero

Homeowners who are interested in saving energy usually start with simple measures, such as installing a programmable thermostat, adding insulation to the attic, or sealing air leaks. For those looking to take energy conservation to the next level, many contractors are encouraging the installation of a combination geothermal heat pump and solar energy system.

“It’s difficult to find any disadvantages to installing a geothermal/solar system,” said Rob Derksen, co-owner of Michigan Energy Services in Whitmore Lake, Michigan. “Since geothermal systems run on electricity, the solar array offsets the need to draw from grid power. In addition, by installing a solar array, homeowners can essentially pre-purchase their future electrical needs at today’s cost.”

If a customer is not going to install both systems at once, it is preferable to install the geothermal system before the solar PV system. “Too often, people make the mistake of covering their homes with solar panels before they call us. We regularly see homes that have a 10-kW PV system when they need much less energy after we install geothermal. Then they have a ton of excess power they don’t get reimbursed for, which is a waste of money.”

Of course, becoming net-zero has a high price tag — sometimes into the high five figures — but, often, these customers are concerned about the environment and just want to be green.

It’s often true that geothermal/solar customers care less about payback and are more interested in being self-sufficient and on the cutting-edge of energy efficiency, said Colin Wunder, president of Howard Heating & Plumbing Inc. in Howard, South Dakota. “But that’s starting to change as more contractors understand the concept and the system design.”


To that end, a geothermal/solar system starts as all HVAC projects should, with the calculation of the building’s design loss/gain and the selection of the geothermal heat pump to cover those loads, said Wunder. “Then you have to figure out the amount of geo-exchange loops needed as well as the solar fraction availability at the project’s location. Then there are associated considerations, such as fluid coolers or other intermediary heat source/sink elements, and the intermediary, latent-fusion-capable thermal battery.”

Designing a geothermal system is almost always more complicated than designing a traditional air-source system, because there are so many additional factors to think about, said Givens. “You need to consider how to make the connection between the loop and earth; what type of grout or backfill is going to be used; how problems can be isolated decades later, if needed; how the system can be designed to reduce service costs; how to protect the site when drilling for wells, etc.”

Geothermal and solar energy will eventually be adopted into the mainstream of home construction and renovation due to policies that favor the environment and the concern over climate change as well as the cost of fossil fuels. Right now, the cost for fossil fuels is relatively low, but it is only a matter of time until we see these prices rising again.”

Love agrees with that assessment, noting that sales of geothermal/solar systems will probably slow for a little while after the tax credit expires. “People will need to get over the pain of losing the tax credit, but I don’t think it’s going to be much of an issue after six months. With the cost of energy going up, it will make more and more sense to install these systems, especially in new homes.”

Love would like to see the geothermal tax credit extended. “What would really help is if we could get Maryland to treat the installation of the geothermal well field as a tax assessment, and homeowners could pay toward that cost for 20 or 30 years. But, short of that, I would encourage everyone reading this article to contact their congressperson to see if we can get the geothermal tax credit extended. That would help us all out a lot.”

This entry was posted on Sunday, July 17th, 2016 at 6:33 pm. Both comments and pings are currently closed.

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