Location: Ray Twp, MI 48096

I am getting a Envision ND074 unit installed in my new construction house. They are digging the horizonal ground loop next week.

I have an existing pole barn 100 feet from the house, right next to where the loop will be installed.

Currently, the ND074 unit is slightly larger than what I need, because I may finish the bonus room down the road, so I wanted to be too big, and not too small.

Anyways, my geo dude came out today, and suggested that I could heat/cool my 20' x 10' office in my pole barn as well with the current looping thats going in the ground for my house. And he has an extra used 3 ton unit in his shop that he removed from another job to put a larger unit in. He said I could have the unit (with installation) for around $2,000

He said the 3 ton unit would heat/cool the entire insulated 40x40 section (office is included in that measurement), but he said there is not enough loop in the ground, and i would need approx $4,500 more if I wanted his used 3 ton unit to heat/cool the entire 40x40 area instead of just the office. I only really need the heat in the winter for the non-office area, so the $4500 is not worth it to me.

I was planning on just running a 220V wall electric heater in the winter in the office, and a ceiling fan in the summer, but this geothermal addition would be much more comfy!

I already have the entire 1/2 of the barn insulated (1.5" foam around outside, ceiling is fiberglass batts), and ceiling too. the office is inside this isulated area, and is isulated again as well with 2x6 fiberglass batts, since I was going to heat this all winter, and only heat the larger portion occassionally.

Any ideas, drawbacks, opinions, or suggestions?

In my kneck of the woods a heated and cooled pole barn is a common event. Our office manager Jennifer has a three ton open loop in her pole barn and the cost to operate that is negligible. The comfort level is over the top! It is a choice albeit over the top but since it is what we do, we could not bear for her to get a propane tank installed for her pole barn. Hope this helps
Eric

A 3 ton for 200 SF is a bit much. A nice console unit might be a good fit.
j

Yes, its WAY overkill, but the price is right; and if I ever did heat/cool the entire barn, I would be all set.

how much is a console unit? got any good ones for sale :)

Price is only "right" if you get what you need for a discount. You will use much more juice than required to run the thing, short cycle it cause extra wear and tear on parts that have shorter or no warranty....
I priced consoles awhile ago and can do some research, but you need your guy on board to get it installed. I know it will be more than $2,000.
J

Using 3T to heat / cool 200 SF would be unworkable unless you like being in a wind tunnel.

If the barn was to be heated / cooled only occasionally, open loop might provide a low cost solution.

If heating pole barn could be done without during very cold weather, it might be possible to work it off the existing loop field without enlarging it. In other words, you'd have to be willing to shed the barn load on the loop during near-design or colder weather (you could use heat strips if necessary)

I agree with Curt, put the 3 ton on the loop. Chances are that you are not heating the barn to 72 degrees, so the load on the loop will be significantly less. Use it for the whole barn, otherwise it is overkill. Even if the loop drops, lets say 28 degrees vs 32 degrees are not a disaster, but only slightly decrease efficiency. For sure much better than solely electric heat.....

Thanks for the tips.
The office will be kept above freezing at all times.
The rest of the insulated barn, will only be worked in 3 or 4 days a week, so that doesnt need to be heated all the time.
Im just trying to decide if its worth it to use the geothermal unit for those 3 days, or if I should just get a 200,000btu natural gas unit to quickly heat it up for those days

An oversized gas furnace will heat it quickly, but be uncomfortable and inefficient while maintaining a setpoint unless it is a modulating furnace - more $ up front.

Nat gas vs electricity unit costs are also factors to consider.

I can get a madium sized natural gas heater for free, I will just need to run nat gas lines from the house to the barn. Electricity is already there for the wall unit or geo thermal unit.

Just an update, I ended up running a 220 wall unit, just a heater, to heat the office for now. I will do something next yera for the rest of the barn. thanks for advice