Pros and Cons of Mitsubishi Multi-Zone Air-Source Heat Pump
Hi All- I’m part of a community program in Tompkins County NY advocating for both ground sourced and air-sourced heatpumps. I am still a little uncertain what to tell people when the participating installers recommend the multizone units. In particular, I am concerned about the MXZ series. They have good heating performance down to low temperatures, but, as pointed out in a previous blog here, they have the very high minimum heating capacity suggesting a lot of needed on/off cycling during the shoulder heating seasons. It seems like both the high minimum and the fact that it is likely the whole house on one compressor might make this activity more dominant. For instance, I myself am, getting a few single head units with better low minimums and also the option of not even turning them all on if weather is mild.
But I have no sense of how large this effect will really be for the MXZ. Does anyone have any more quantitative boundaries to put the energy efficiency loss in perspective? I could also imagine that the fact that the whole house is on just one compressor, so only one compressor is cycling on and off instead of several compressors for single head units might be a good thing. Does that make it less of an issue? Any help with this will help me advise other people participating in this program.
I’m also wondering if the larger size of the multizone units (quite a bit taller) could be a little bit of an advantage during high-snow conditions. Harder to bury it because they are much taller. I’m sure they still need to be kept clear at the base for the long run, but is there less liklihood of being completely buried during one storm and is that much of an advantage for immediate reliability and performance during storms?
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