Mitsubishi mini split branch box efficiency
I currently have a Mitsubishi mini split system (MXZ-4c36NA) which supplies 4 units in my 1985 home (2 x MSZ-GE06NA, MSZ-GE12NA, and MSZ-GE18NA). It was installed mostly for AC, but we have really loved it for heating as well (Zone 5, New Hampshire), while still relying on our old oil heater for the coldest parts of the winter. Now our oil furnace is on it’s last legs (good riddance), so we are looking to switch entirely to the mini splits. We have solar panels and currently have a surplus/credit with our electric company. I will need to add a unit to the entryway which is currently not covered by the 4 units we currently have.
I had the original contractor come take a look and give me a quote on upgrading the outdoor unit to a Hyperheating one so we can use the system through the winter. I have not received his quote yet, but while he was here he said something that I have not found anywhere else. He said that I would be better off having 2 outdoor units so as not have to have a branch box, because the branch boxes are inefficient. Is that true? He specifically mentioned the defrost cycle, although I am not sure why the branch box would significantly influence that in a negative way.
On a separate but related note. If I do go ahead with this project, what does one do with the old but still functioning unit.
Thank you in advance.
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