I have a ranch home that is being built in Michigan it is 2,190 square feet on the main floor and about the same in the basement. I will have ICF basement and 2x6 Blown in insulation with R50 in the attic. My question is what is going to be the best geo closed loop system. A water furnace guy tells me that the heating BTUs is 83,000 and he said a 5 ton is the best. Another go guy said I need a 4 ton and he did not give me the heating BTUs. Climatemaster Plus do you think I will want to zone the basement different from the main floor. I also met with a guy that does home audits and he told me my top BTUs was 60,000. I gave all the guys the same prints of my house and I am getting all these different numbers. Could you please give me your thoughts on what I should do. Thanks for all your help

If you have ICF basement, and R50 attic, the only way your heating load is 83,000 is that the heating guy is really fudging the numbers, IMHO. Maybe he figured on you leaving a window wide open. I really get tired of people not trusting Manual J.

I would still want the 5 for 60k
others have recommended getting the 50 buck load calculator via some web page and running your own numbers to confirm
seemed like sound advise so I thought I would parrot

Most of the 2000Ksf houses I see are in the 60 to 80 range and usually a 4 ton is more than adequate (95%) of the load. I expect 5 ton would be too large, I would take a stab in the dark and say home audit guy didn't allow for the basement.
I would suggest another opinion to break the tie (the auditor doesn't count as he is not installing anything that he has to back).
Good Luck,
Joe

I just got another heat loss and the guy said 59,000 Btu and a 4 ton plus I asked the climatemaster guy and he said 66,00 Btu. So I think that a 4 ton will be the best what do you think. Also do you think I will need zoning for the basement. I just dont want the basement to be colder. If I set the temp at 70 on the main floor about what do you think the drop will be in the basement. Thanks

Don't make the error of assuming that a "ton" equals 12,000 btus, especially in a northern climate.

For example, a nominal 64,000 btuh Waterfurnace produces only 46,000-47,000 btuh with 30 degree entering water - a not unlikely circumstance late in the heating season in Michigan.

Wether there is a drop in the basement depends on ducting. It doesn't have to be handled with automatic zone dampers, it just has to be balanced. If your wish is to control it seperately then you will need zone dampers and IMO a 2 stage heat pump.
I'll throw a qualified agreement on the 4 ton size. While it sounds right, I've no way to verify it. That you recieved 3 opinions between 59 and 66K that sounds good. I would ask the fella at 80K to double check his numbers and why.
J

Hello Joe,

In your comment above, about the adequacy of a 4 ton unit meeting 95% of the load, are you referring to the design load, seasonal, or annual heating load? Thank you.

Regards, Masoud

Annual heating; I use the same geo design software as your installer I believe.
J

we live in the u.p of michigan. have about 1000 sft ranch style home with all cathedral ceilings. we just installed econar geosource vara 2 plus 4 ton. i was concerned that it was oversized. wrote the manufacturer and they said this model is generally adequate for 800 sft to 1600 sft home. out of 3 estimates we got 3 sizes. a 2 ton, a 3 ton and a 4 ton. go figure

I suspect the 4 ton is covering about 99% (if not 100%) of your requirements in the U.P. I'd have probably leaned towards the 3 or even 2 ton. Of course without knowing the manual J heat load, we're guessing.
There's not too many down sides to oversized systems as long as ducts are adequate, but I can tell you based on a load calc I recommended a 3 ton today for a house over 2,000 SF (loosely 55KBTU). A 4 ton would work as well but cost considerably more with little savings.
j