Hi Chris, thanks for the question.

The implementation of a geothermal water-source heat pump system comes with the long-term benefit of lower maintenance, no visible exterior equipment, and of course energy-efficiency. But these benefits also come with a very high upfront cost, though there may be rebates or other financial incentives to help offset this.

When you’re approaching an HVAC renovation, there are typically three questions to consider:

1) What type of building or space are you working with?

2) How much do you want to spend, and

3) What type of space is available to accommodate the new system?

The answers to these questions help set the stage for the most important overall question, what are your priorities for this retrofit? Are you looking for the most energy-efficient system possible, no matter the price, or are you willing to balance energy-savings and environmental benefits with upfront costs?

I’m assuming that since you’re asking about a geothermal heat pump system, you’re interested in energy savings. And it looks like in your area; there are lots of tax credits, utility loan and rebate programs to choose from (you can find more information about the programs available in your state at DSIREUSA).

The Blue Ridge Electric Cooperative, for example, offers a geothermal heat pump loan program with 7.5% interest for up to 60 months to finance any amount from $500 - $12,000. And Progress Energy Carolinas offers a 5% discount to its residential customers who have Energy Star certified homes.

Given your climate, whatever type of system you pursue should have good dehumidification capabilities. While a DX cooling system might be the most efficient at dehumidification, your proximity to saline ocean air might take its toll quickly on any exterior split-system components, so I’d recommend checking with your contractor if any stainless steel or anti-corrosion coatings could be implemented to prolong your equipment’s life if you go that route.

Since you mentioned the ground-water table is relatively high in the area, a newer geothermal technology that might be of interest to you is a patented geothermal ground water system called Aqui-Flo. This system utilizes one well to operate on an ‘open loop’ principle in which groundwater is extracted and circulated either directly or indirectly (using a heat exchanger) from a lower point in the well and then rejected to an higher level. Preferred conditions for such a system are a sand/gravel aquifer with above average water quality (pH, hardness, etc) and a moderate aquifer flow velocity.

Ultimately there are many questions and systems to consider based on your answers. I’d recommend looking up a knowledgeable contractor or engineer in your area to assist.

Best of luck!

Related Advice:

• Geothermal Heat Pumps: How Do They Work?



• Geothermal Research: What to Consider with Geothermal Heat Pump System?



• Geothermal Tax Credit: Why Doesn't My System Qualify?