Ducted Minisplit: Mitsubishi vs Carrier
Hi all —
We’re building a well insulated two-story ~3500sqft home in the 3C climate zone. We have hydronic radiant heating in-slab (first floor) and also under floor (second floor). For cooling, we plan on installing a single heat pump and three ducted mini-split units (two on the second floor mounted in the attic, one of the first mounted in drop ceiling). We know this is fairly “extra” by GHA standards – but we are prioritizing comfort.
Our original plan was to go Mitsubishi, however our HVAC subcontractor is proposing a “1:1 / like-for-like” swap to Carrier equipment (model numbers unknown). The installer is Carrier certified and claims better product availability now and also parts availability in the future (they claim they’ve had trouble getting replacement parts from Mitsubishi in the past).
The original Mitsubishi proposal was:
• PUMY-60KNMU Heat Pump
• PEFY-P24NMAU-E3 (downstairs)
• PEFY-P18NMAU-E3 (upstairs)
• PVFY-P12NMAU-E (upstairs)
Our architect has said the Carrier equipment proposed is “comparable.” Should I push for Mitsubishi equipment — even if it’s at a premium? If we went Carrier — what line should I push for? Am I overthinking this?
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Replies
Mitsubishi is the better of the 2 choices and you will pay a premium. Mitsubishi support is the best among all ductless manufacturers and that's why I sell it. Ductless equipment is reliable if installed properly but very sophisticated, having great factory support is important. Carrier "ductless" is made by Media in China. If you like your installer and he is familiar with Carrier and will support it after the sale, I wouldn't sweat it.
Hi Rich -- appreciate the reply! We are going for *ducted* minisplit over ductless so we can minimize wall acne and to get distribution into a few larger open/vaulted spaces. Does your answer change given it's ducted over ductless?
Hi, no, the ducted Carrier version would not change my mind. I would agree with Akos that it sounds oversized, so question the HVAC guy on that. They are proposing a 5 ton system, not 9.5 tons as mentioned below. Critics of slab radiant can say what they want about the decadence but nothing is as comfortable as a "warm" slab. (OK- I agree its rarely warm if the house is high performing, but its not cold either). If its in the budget, I would agree with radiant in the slab if its installed well with outdoor reset controls, etc.)
Unless your house is made of all glass, there is no way it will have a 5 ton cooling load.
Before looking at brands have somebody competent (ie hvac engineer) run a proper man J on your place. In a well sealed place with decent window shading, you are probably in the 2.5 ton range.
Most likely Carrier equivalent 2.5 ton unit would be this:
https://ashp.neep.org/#!/product/30601
This is actually a rebaged Midea multi split which is an excellent unit.
More important than the brand is proper design, sizing and install.
My read of the post is that they have specced 9-1/2 tons for heating and cooling. Absolutely nuts. And then they add in-floor radiant as well. They're probably paying $100k in unnecessary HVAC costs.
5 ton outdoor unit with three indoor units. The PVFY and the PEFY units are ducted indoor units from Mitsubishi's City Multi line.
I agree with the premise though, it's nuts. Par for the course though. I'd agree with Akos, it's probably somewhere in the 2.5 to 3 ton range.
Without a proper load calculation, it's all guesswork.
For more on load calcs and why they are crucial:
https://www.greenbuildingadvisor.com/article/who-can-perform-my-load-calculations
Ask to see the manual J as others have said. If you google "btu per sq ft" you'll see 20-100BTU per sq ft, more if it's "sunny". That's how you get ridiculously oversized systems. Funny enough, 20btu per foot is pretty close to what you've been quoted.