I live in Tennessee, and am considering a geothermal retrofit for our house. I have an estimate from a local contractor who I think has a solid reputation. But he is also the only game in town--I know of no other geothermal contractors in the area--so I was hoping to get a second opinion, just to be sure. The estimate is for a 2-ton Water Furnace Envision series unit, with a horizontal ground loop. The unit would replace an ailing Gibson air-source heat pump, but I've been told the existing ductwork should not have to be replaced or wholly re-done (rather, just modified as necessary). The quoted price is a little over $14,000. I can include more info about the house, property and load calculation if necessary (FWIW: 1500 sq. ft. house, two story, built around eight years ago). Thanks in advance for any input you can provide.

What was the calculated load of the house?
What are the predicted op cost savings?
Is it possible to bring the load down some and consider air source?
If you require a 2 ton now, you might be able to spend less than 14K on envelope improvements and an ASHP and have similar op costs.

Thanks for the prompt response. I tried to include a lot of (hopefully) helpful information in my response, but definitely let me know if you need more.

I'm new at looking at Manual J spreadsheets, so you'll have to forgive me if this isn't what you need:

Total BTU/hr Gain - 25704.35.

I was told this load is a shade over what a 2-ton unit is meant for, but part of that was due to purposefully undershooting the attic insulation (access was problematic during inspection, so he erred on the safe side and assumed only the minimum amount; I agreed with that decision, but I'm pretty sure I recall there being more than 6' of insulation up there).

For what it's worth, I inserted my home infomation into a calculator at www.geothermalgenius.org and it spit out these numbers: Cooling Load - 13500 btu/hr; heating load - 24150 btu/hr. It too told me I needed a 2-ton Geo unit. Limited relevancy perhaps, but I thought it was an interesting tool. (of course, it also estimated that the install of such a unit would cost around $9300, pre-tax credit . . . )

The contractor also quoted me a 2.5 ton conventional air source heat pump, which he said would be more appropriate under his load calc than a convential 2-ton unit would be. And another contractor also gave me a quote on a 2.5 ton 14 SEER air source unit (though the second contractor didn't perform a proper manual J calc; he sort of "eye-balled" the situation, and likely also gave weight to the fact that my current heat pump is a 2.5 ton unit). A third contractor quoted a 3-ton 13 SEER, but he seemed to be making a sales call more than a true estimate of what I needed.

The projected savings of the geothermal heat pump are vs. the 2.5 ton conventional unit (a 14 SEER) he quoted me, and include projected hot water savings (we have a natural gas hot water heater).

Projected annual cost of heating, cooling and hot water combined: Geo - $537; 14 SEER air-source - $1,055.

At least one problem with this that I see is that he overshot my annual hot water costs. If you remove the monthly base charge from our gas bill, which we have to pay regardless of usage, our annual hot water cost is only around $90 (the monthly base charge is between $13-$16, and the average total annual gas bill, including base charges, is around $262). Yet he estimated that our current hot water cost was $326. (And that the Geo unit would cut this down to $171.)

I'm also a little skeptical of his projected annual cooling costs for the proposed 2.5 ton 14 SEER. He estimates $338. But using our '03/'04 era Gibson with a badly leaking evap. coil, our cooling costs in 2011 were around $245 (based upon our electric bills).

The convential units I've been quoted are certaily much cheaper. Those three estimates range from $4200 - $5500. And I'm certainly doing some careful cost/benefit analysis of all this (leaning toward conventional right now). I just wanted to see if geothermal quote was reasonable for what it was.

Thanks again for the help!

Yeah the price is probably reasonable. The "missed" guesses on op cost are because of an inaccurate load calc. Op cost calculators also err on the side of caution, but the savings percentage is spot on. Looks like it might be worth going to geo, but you know your budget better than I.
What if you get a blower door test and insulation improvements and drop your current consumption by 20%?......worth a look.

Looks very reasonable, same system (with DSH and 2 tanks) runs about $18 in my area. NY state probably has much higher overhead.

Thanks for the responses.

I liked the contractor anyway; it's good to know the price was on target even when he's the only option around. I'll likely go with him regardless of whether I get a geo or air-source unit.