Mini splits instead of central air, anyone actually living with one?

We put two Mitsubishi heads in our 1950s cape about four years ago and honestly the day to day has been better than the old central system ever was. Our living room is maybe 20 by 24 with a big south facing window, and the 12k unit there keeps the whole space even. I was worried about hot and cold corners because the head blows from one end of the room, but the louver on auto mode swings enugh that you stop noticing. The bedroom unit is the real win, we sleep so much better being able to dial in just that room overnight instead of running the whole house cold to get one room comfortable. Shoulder seasons are where these things shine for us. We run them as heat pumps well into fall, they put out decent heat down into the 30s outside before our old baseboard has to pick up the slack. Warming up a chilly October morning with the heat setting costs pennies compared to what the boiler would burn. The annoying stuff is real though. I rinse the filters in the two heads every month during summer, takes ten minutes but you do have to actualy do it or the airflow drops off and the unit gets louder. The wall units are not pretty, I will not pretend otherwise. Our compressor sits by the side yard and a neighbor ten feet away says she can hear it hum at night if the windows are open, but it never bothered anyone indoors.

We went the other way and kept central, and I'd do it again. Our house is a two story colonial from the 80s, and after getting quotes for five or six heads we paid to have the ductwork sealed and a new variable speed air handler put in instead. The difference in evenness was bigger than I expected. The upstairs went from unusable in July to basially fine, mostly because the leaky ducts were dumping cold air into the joist bays instead of the bedrooms.

The thing that pushed me away from splits was honestly the aesthetics and the maintanence. My wife flat out refused to have units on the wall in the bedrooms, and I didn't want to climb a ladder four times a season popping filters out of each head. With central it's one filter, one location, takes me two minutes.

I'll admit the tradeoffs. Summer bills are higher than a neighbor of mine with splits, probably noticeably so, and we lose the ability to only condition one room. But we allready had the ducts, so the incremental cost was way less than a whole multi head install, and we kept one thermostat instead of a pile of remotes.

If your ducts are truly shot, get them inspected with a camera before deciding. Ours looked terrible from the register side but were mostly just disconnected at a few joints, which a crew fixed in a day.

I agree with the person who mentioned the neighbor noise. It is definatly something to consider before you go all-in on a mini split setup. I also found that the proffesional installation quotes varied wildly depending on the unit's placement. We had one company charge us double just for running a new line and adding the required drainage, even though the unit was going right outside our door.

I put a single 9k head in my upstairs office myself with one of those precharged line set kits, and the install was way easier than I expected. The part the videos skip is the condensate drain. Mine sags a little where it runs along the wall and the water sat in the pipe until I re-pitched it, then it dripped green gunk on the siding for a week before I figured out it needed a proper cleanout. So factor in a place for that water to go when you're picking where the head mounts. Two winters in and it's been fine otherwise.

A similar thing happened when I looked into it. The electrician told me my main breaker was way too small for what we were planning. They said running multiple units would just trip the service, so we had to upgrade the whole electrical panel just to support the load. It wasn't cheaper than we hoped, but now we know what kind of hidden costs there are with the electrical side of the job.

Regarding efficiency, it is critical to look beyond the SEER rating and consider the Coefficient of Performance, wich really dictates the operating cost when running them continuously for long periods. Most users overlook that while the instantaneous cooling capacity is often robust, the longevity of the sealed refrigerant charge over time can lead to performance degradation unless the unit is properly maintained and monitored. I have found that the internal evaporator coils do require periodic chemical cleaning, far beyond the routine filter rinse, to prevent airflow restriction and optimize heat exchange. This adds a layer of required maintenance that is often unmentioned in the general consumer reviews.

Update: took the advice about getting several quotes and yeah, they're all over the place. One guy quoted double another just because of where the outdoor unit would sit. Now I'm stuck on placement, since the only sensible wall faces my neighbor's bedroom window. Anyone find a workaround for compressor noise, like a pad on the far side of the house or a small fence screen?