We have a 3-story home with our apartment on the first floor, a tenant in apartment 2 on the second floor, and a large unfinished and poorly insulated attic on the third floor. There is also a basement which has the boilers for heating both apartments with radiators. Each apartment has two bedrooms and is about 870 square feet (see attachment). Currently the "window" AC unit that was installed in the wall in the kitchen without a sleeve, is not working; it broke down late last summer and is old and noisy. I think it's 12,000 BTU, and with the ceiling fan in front of it was good enough for the whole apartment; we did not attempt to cool the front porch which is enclosed. We do happen to have a very noisy secondhand portable AC that we made do with when our AC broke down last summer (and we were all mostly at work or daycare during the day). Tenant upstairs has a window AC.
We are in an HCOL suburban area in USA, hard hit by COVID-19, not far from New York City which means 4 seasons, hot humid summers, cold winters. DH is working from home and it's getting hot. He was using the attic, but at this point it's getting unbearable up there. He's used our front porch, but that is also getting uncomfortable. He's now outdoors on the back porch and may use the basement next. I'm not working at the moment due to disability but likely to work at least partly from home at some point. We also have a young kid recently back in preschool (private for now due to pandemic), but might be home again all day if things start shutting down again. Basically it's worth investing in keeping the place comfortable enough to be productive here. Neither of us has previous experience with central AC or mini-splits, mainly just clunky old window units, and we are not very handy.
I've been emailing back and forth with an "elite" installer for one of the well-known, more expensive mini-split brands. He seems super busy and like he doesn't have time to hold my hand and pore over my every thought and question with me. He is giving me a quote based on photos and emails. Originally he was going to suggest a lot of units but I asked for something much more pared down, like one unit for each floor. The quote is over $10,000, with a 12-year warranty, for a 3 ton condensing unit, one 9000 BTU head unit on the first floor, one 9000 BTU head unit on the second floor, and one 12,000 BTU cassette unit in the attic. The condensing unit appears to have both heating and cooling; I had mentioned the idea of being able to heat the attic, but I consider this aspect optional.
Some thoughts I had:
1. This is more than we'd like to spend at the moment. We could make do with just cooling the first floor for now. We don't even use the second floor, frankly, and the rent is way below market. It would be nice to cool the attic, but not a necessity at this time. Also, what I end up not liking mini-spits for some reason?
2. I asked if it makes sense to do this in phases, like one floor for now and add the others later, but he said not really because later the equipment could be incompatible.
3. I had been thinking one condensing unit could be enough and the quote reflects this thought, but now I'm thinking that since it's a multifamily, maybe the first and second floor systems, at least, should ultimately be separate. That way it could be set up so each household's usage is reflected in their own energy bill -- yes? Also tax-deductibility would be simpler. Not sure how to handle the attic, which we currently use for storage but may eventually do something else with.
4. If each apartment should have a separate system anyway, we could just do the first floor for now. Ideally we would cool the enclosed front porch, which can be used as a workspace.
5. If we just do the first floor, would we just have one condensing unit with cooling only, and just one head in the kitchen wall where our defunct "window" unit currently is? If so is 9,000 BTU enough? What if we attempt to also cool the enclosed front porch (by opening the hallway door, or just the window between living room and porch, and maybe moving the air with a fan)? Remember, I'm not familiar with mini-splits, so not sure if I think about them the right way.
6. Noise level and clean air are very important considerations for us, affecting productivity and disability. I thought mini-splits would be best, am I right? And, I know this isn't "proven", but I am not convinced that there is no such thing as health effects from EMFs, so I like the idea of the condensing unit not being really close to where anyone sleeps or works. My experience being mostly with window units, I'm used to turning on ACs only when needed and using windows and fans more. How different is having a mini-split? What if I don't want to run it 24/7 because of noise, desire for fresh breezes, or even EMF stuff. (Please let's not spend too much of this thread on discussing the lack of evidence that EMFs are harmful.)
Uhhhh thanks for reading, please share your knowledge, and please help me think about this :)