Minisplit sizing and location
Bear with me while I first give you some context about my house.
My 960 square foot home (2 bed, 1 bath) can get pretty warm during the summer. It is a 95-year-old tudor style home with lots of original wood casement windows (which I plan to keep).
There is R38 insulation in the attic and none in the walls. The house is only 4 miles away from the ocean and it’s regularly pretty cool (West Los Angeles), but there can be 20-30 days per summer when the rear of the house (facing south) can get very hot. (The kitchen and dining room are at the rear of the house — see attached floor plan.)
I plan to install swing doors in the two doorways that lead to the dining room and the kitchen (where the house gets the hottest). As a result, I would like to install two mini-splits. One in the kitchen (perhaps near the back door, facing length of kitchen) and a second one perhaps in the living room. I’m concerned over a few things:
(1) Whether a 9k btu in the kitchen and a 12k btu in the living room would be sufficient for the respective spaces they will cool? Or would it be overkill? (Note that I would try to avoid having both units on at the same time, because my plan is to zone, using the swing doors.)
(2) What is the proper location for the unit in the living room? So far, I’ve concluded that I should install the unit on an interior wall (on wall shared with linen and bedroom closet), and would run the AC lines up through attic and out to outdoor unit installed on flat roof over kitchen and bedroom. (The reason I don’t want to install the unit on an exterior wall is because that wall faces the street and I don’t want unsightly AC conduit lines.) The water line would likely run down wall of linen closet and into basement, to a floor drain. Problem with this location is that it would blow cold air in direction away from bedrooms (one of which can get pretty hot during the summer). Am I setting myself up for having to install 3 headers? (Perhaps a third in the rear bedroom, which is the one that gets the warmest?) For such a small house, 3 headers seems excessive.
(3) Finally, if I install more than one header in the house (two seems likely), does it make more sense to buy a multi-zone unit (i.e. connected to one outdoor unit)? I would install the outdoor unit on the flat roof that sits above kitchen and rear bedroom.
Thanks for any input.
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