How to size a mini split for a small addition?
I’m planning a 2nd floor master bedroom addition and I’d like to heat and cool it with a mini split. Using a couple of online calculators (e-comfort.com and loadcalc.net) I’ve come up with about 5000 btu cooling load and 6000 btu heating load. Looking at the Misubishi H2i units, it looks like both the FH06 and the FH09 have the same minimum capacity range of 1600-1700 btu. The price difference between the two is about $100 with the 09 being somewhat more available.
My question is, will either unit be more efficient for my application and would I be problematically over sized with the FH09? I’m considering the larger unit because I expect we will often leave bedroom and bathroom doors open which will leave the addition somewhat open to the older parts of the house.