Minisplit heat pump sizing issue
I am hoping someone can point me in the right direction.
We are thinking to add mini split ductless heat pumps to our existing 1550 sf raised ranch in Manchester NH. The house has good insulation for the age with R50 in the attic and 15 year old windows. It has 2×4 walls so not sure about R-value there. Currently have hot water baseboard heating system with 25 year old oil fired boiler and our oil consumption averages about 450 gal / year.
We had contractor do head load/loss last year, but my fear is that he used higher design temperatures that those specified in the Manual J catalog which for Manchester NH are (-3 and 88). He used (-20 and 95) so I am not sure if his designed temperatures would affect size of the equipment. For living room he recommended Mitsu MSZ-FE18NA but I think it’s oversized for our living room. My plan is to use Fujitsu 12RLS3(H) or non H for living room and Fujitsu 12RLS3(H) or non H for open area that includes (dining room, kitchen, entry area). For the 3 small bedrooms I would go with multi (3 zone) 7RLF1. I think this is oversized for the size of our bedroom but these are the smallest Fujitsu units.
Attached is heat load/loss for your reference.
Please let me know if my thought process is right or if you can point me in the right direction.
Looking forward to your feedback.
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