Geothermal heat pump for shop

My shop is 40x50x16. Has anyone had any experience putting in a heat pump with a geothermal ground loop. I planned on buring the loop at least 9 feet deep. Have radiant heat in the floor now. Looking for a way to cheapen up heating costs in the winter. Looking at all options from using wood to heating with biomass to geothermal. Opinions please.

I'm not an expert, but with that kind of volume, you will need quite a geothermal system and a massive ground loop I think. I would guess that it would be a very long time before that investment paid off.

If you want to save costs, and you already have the in-floor system, I would recommend an outdoor wood-burning water stove. I have a Taylor that has two inserts in the back for radiators that you can use for potable hot water heating. You can also use them for in-floor closed loops. The only downside is that you have to keep feeding the fire all winter or the main tank (open system) will freeze up.

Have you looked at solar hot water heat? There are some really good designs, the only downfall I can see is that you need a sizable storage tank to keep your heated water. If you already have in floor heat now you're already half way there. Even if you were to use the solar in conjunction with your present source you could easily see your bills drop by 1/2 or more with a properly designed system.

The geothermal will work,not necessary to bury lines that deep.They coil them up now so you don't need so much trench.Heat pumps don't work very well in cold temperatures and use a lot of electric.I would use your existing radiant as a backup.I've had geo at my house for two seasons and can heat my house in an ohio winter for 250 bucks or less.

Don't use the coil (slinky type) everytime the lines cross you lose a little capacity, use the trench method, a little more time but a lot better system. We have put geo into 2 shops and are 1/2 way through the 3rd. A couple things to remeber, geo runs at a cooler temp than a boiler, takes longer to get the concrete mass heated up, You need a really good thermal barrier between the slab and the ground, or alot of the heat will go down. If you don't have enough tubes in the concrete it may not heat correctly either

Payback is going to be measured in decades and the unit will be worn out by then with ground loop.
Water source from an existing well and returning to a ditch/creek/pond is the most economical geothermal.
I have kicked around the idea of just using ground water and a heat exchanger. Ground water is approx 50F here. That would keep a shop and floor from dropping below 40F.
If you are dry and out of the wind, 40F isn't a bad temp to work in. Local spot at a work bench from an overhead electric infrared heater would be all that's required.
Of course no source of heat or cooling is economical with the wind blowing under the equipment doors and around the eaves.

Payback is going to be measured in decades and the unit will be worn out by then with ground loop.
Water source from an existing well and returning to a ditch/creek/pond is the most economical geothermal.
I have kicked around the idea of just using ground water and a heat exchanger. Ground water is approx 50F here. That would keep a shop and floor from dropping below 40F.
If you are dry and out of the wind, 40F isn't a bad temp to work in. Local spot at a work bench from an overhead electric infrared heater would be all that's required.
Of course no source of heat or cooling is economical with the wind blowing under the equipment doors and around the eaves.

we put a geothermal heat pump in our shop 2 years ago, it"s 40x40x16ft shop, with in floor heat, and also connected to a 20x40x8 store shed, which has no heat except what the air moves in from the main shop(10x8 door between the 2).

Our loops are 300ft long and 6 feet deep, 2 loops per trench - trenches are 4ft wide, and there a 3 trenches... works fine, off the top of my head i can"t remember how big the unit is, but it has no problem in keeping the shop warm, even with opening the 24x12 door at least twice a day in winter...

FYI i"m in Manitoba, and -40 happen ever winter without fail in our corner of the world.


I looked at using either a wood furnace or coal furnace too, but the geothermal system wasn"t much more expensive than installing a new coal furnace and hopper bin... and wood is hard to automate...

Question. If, when installing new building, could you put the ground loop in under your concrete floor to recapture any heat lost due to going down from under floor?

I've had geo for over 10 years in my house there are a few things to consider: First of all you need 500' of pipe underground per ton of heating/cooling weather it is spiraled or straight, I don't know about other areas but my zone in SW Ohio the piping only needs to be 4' deep I'm guessing the frost line. Winter in the nortern areas maybe iffy because it relies a lot on backup heat in extreme cold weather I have 30KW electric heaters as backup but I've added a propane fireplace to augment that. Geo is not a power saver by any means for heat unless you can get a special rate from the power compnay which I have right now but can change anytime. Works well in late fall and early spring but winter is a bust the payback is extreme hot weather when the wet bulb is high and the system can send the heat to a cool place. I would make changes if I do it again but am working with a firm to correct some short comings coupled with a windmill but that is a long way off. In summary it is great if the world keeps heating up but is not so efficient in cold weather areas in the winter. My biggest problem is the reliability of the recirc pumps for the glycol I've lost 4 in the last 10 years at close to $200 ea.

I would think that the best dollars spent would be on a large wood furnace or pellet furnace. Geothermal may cost you over $8,000 material and labor. A pellet furnace or wood furnace would be half or less then half of that.

I solved my geothermal generated high electric bills with a 7500w solar array on my barn roof. It's tied into the grid, all legal like, and cuts my electric bill by 2/3rds. My house is 3000 sq. ft. in CT

Solar panels are cheaper now with a 20-25 yr life, and no moving parts to replace. Best complement to a geothermal system.

The cheapest way to heat any building is INSULATE, INSULATE, INSULATE!! Make any heating system you install pull the return air off ceiling and send it back to the floor. I will have 90+ degrees on the ceiling and snow on the garage floor. I heat a 28x44x16 by using 1/2 gallon/hour nozzle in an old oil furnace and pull in some outside air and the rest of the air is off the ceiling.