Cold Climate Central Ducted Heat Pump Recommendation
I have a net-zero-ready renovation project where we’ll be selecting HVAC equipment soon. We have low overall loads but a need for distribution with a zone for each floor of a 3-story house. So, I have a “problem” with low loads and a need to select ducted cold climate heat pump equipment (ducted minisplits?) that won’t be oversized.
What manufactures / equipment would you recommend for air-to-air cold climate heat pumps for my scenario?
Here are the details.
Net-zero-ready renovation of a historic home in southern Vermont (zone 6).
HVAC design (Manual J, S, D, etc.) will start soon. My HVAC (and plumbing) contractor is agnostic about specific equipment vendors. We expect to purchase equipment from our local supply house (FW Webb here in New England) but can consider other sources too. Vendors who have good records for reliability, and parts and support availability when needed are preferred.
I’ve performed some preliminary load calculations and expect my heat load will be somewhere around 35~40k BTUs/hr total for 4,000+ sq. ft. of living space. The house has three floors of living space (1st, 2nd, 3rd floor) and lots of smaller rooms. Our plan is to have ducts in the basement with an air handler to hit the first floor and ducts around the perimeter/eaves of the 3rd floor with air handler(s) on the 3rd floor to hit the 2nd and 3rd floor rooms. Basement is in the insulated envelope and the heat load includes it, but it’s storage/mech only and we don’t plan on conditioning it directly.
I anticipate we’ll end up with either an air hander for each floor or, perhaps, one for the first floor and a single air handler with a zone control for the 2nd and 3rd floors.
Here are the preliminary heat load calcs for each floor (= each zone). This is from spreadsheet work, not an actual Manual J (yet), with -4F outdoor, 70F indoor design temps.
3rd Fl: 11k
2nd Fl: 10k
1st Fl: 16k (6k of which is basement)
So, yeah, about 1 ton each for the 2nd and 3rd floor, and 1.5 ton for the 1st floor including basement load. If we had an open floor plan this would probably be a “just get a mini-split for each floor and call it a day” scenario.
What do you recommend? Are there some ducted mini-split options that would be a good match for this house?
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