I just got a quote for geothermal installation and I want to know if it is reasonable.
I am building a small addition and want to install geothermal to heat/cool new space as well as retrofit remainder of house.
Quote is for 3 Climate master units.  A 3 ton and 2 ton to replace my existing heat pumps (use existing ducts).  Addition will require an additional 2 ton unit plus some duct work.  All three units with variable speed air handler.  3 honeywell vision pro 8000 thermostats.  7 150ft. geothermal bore holes of 1" vertical ground loop piping.  1 unit with hot water generator.
Quote is for $46,500.  I estimate $1100 savings per year in electric bill.  Thats a 40+ year return on investment before tax credit and ignoring electric price hikes.  Does anyone know if this quote is in the ballpark? Thanks

Much depends on where you live. Costs are much higher in the coastal west and northeast.

That said, in very ballpark numbers the units could be $15k, bores $10-12k. Add to that the rest of the materials and quite a lot of labor and it may not be totally out of line.

If you are to save only $1100 per year this may not be a good project for you.

You might check into zoning. If feasible it could save some money. The price of a 3 ton and a 2 ton unit greatly exceeds (several thousand $) the price of a single 5 ton.

another option would be to go for one 6 ton water to water unit and then do air handlers for each zone. This should save some serious cash.

In my opinion as a homeowner, it is smart of you to ask whether quotes are reasonable. To ultimately know if you are getting a good deal, you should also get multiple quotes from the same and different manufacturers. Sometimes paying more gets you more, and sometimes paying more does not.

Cash is cash. If you expect to reap the full benefit from the 30% tax credit, I would factor that into your payback. How old is your current equipment? We would have had to either replace our old units with conventional units, or go geothermal. We had quotes done for both. For payback purposes, we thought it perfectly reasonable to use the cost for the geothermal (after the tax credit) less the cost of the conventional system, then divide that amount by the expected utility savings.

Are you including the cost of the geothermal unit for the addition and the additional operating cost for it as well in the payback? I wouldn't. I would look at these costs separately (for payback purposes) from the rest of the house. Including these costs will make the payback appear less favorable since there are no savings included compared to a conventional system for the addition (unless you factored this into your figures somehow.)

Are you factoring in that the geothermal system may last much longer than a conventional AC or heat pump (if these systems are the alternative to going geothermal)?

If any of the "other" two units will be relatively close to the water heater, you may be able to have more than one desuperheater (DSH or hot water generator). We have 2 DSH's and like the results.

Are your loops planned as 3 dedicated loops for each of the 3 units, or are they shared loops? Our shared horizontal loop works very well, and was less expensive than dedicated loops. I'm not sure if this would be the case with vertical loops.

Share the loops, for sure. No point in having one maxed out and another loafing.

Dewayne makes an interesting point that I need to wrap my mind more fully around. Zone diversity almost certainly means a single 6 ton would meet total load of 3 separate 2+2+3 ton units, and the single six would cost half or less of the 3 separate units. Water lines are a heckuva lot easier to route than ductwork, and the minimum zone airflow constraints characteristic of current two stage technologies vanish with a chilled water-based system.

Size the buffer tank reasonably and the unit gets decently long runtimes for efficiency even during periods of low load. I guess it wouldn't even be necessary to spring for a two stage unit.

Sensible vs latent ratio could be managed as needed by adjusting buffer tank temp setpoint. I guess 50 degree water would work in the desert but we in the southeast would go for 40-44 or so.

I potentially have a 8k SF house with 3k SF guest house project coming up, and a water-water system might be the ticket. It'll probably come in at 10-12 tons, so two six ton units might get 'er done with infinite zoning possibilities.

How did you arrive at a $1,100/yr savings estimate? Do you have natural gas available and high electric rates?
We pay more like $2,600/ton vertical bores with loops so $18,000 there + 3 heat pumps.. you didn't mention whether electric, DSH and buffer tanks were included so to the price question....maybe maybe not.
Curt, the beauty of water to water among other things is that sizes go larger (you can get a single ten ton). RE 2 stage I have been told by my manufacturer's rep that 2 stage wtw is the only tax credit eligible unit.
Joe