I've toyed with the idea of these mini splits. They're not all that expensive compared to big window or portable units while being more efficient. I think they are DIY too which is nice.
But I figure for maybe double the cost I can just get central AC installed and do the entire house, so that's probably what I'll eventually end up doing. The nice thing with central AC is there is a full blown air movement throughout the whole house so it's better to get rid of humidity, at least I would imagine so. And of course the benefit of cooling the whole house. I find even with my 1 ton portable unit, I can get my home office down to like 20C when it's 25 in the rest of the house, but as soon as I turn it off it starts to climb fast because all the other rooms are hot so it quickly brings the room back up in temp.
On the other hand for the little that I need AC it's hard to justify paying a couple grand for central AC. Every summer I toy with the idea of finally getting it done, then suddenly it's fall again.
The problem, at least in my area, is that a 1:1 H2i unit (indoor/outdoor) is about $2k installed. So if you want say five of them for your house (let's say 3 bedrooms, main room, and kitchen), you're looking at ten grand easily. Versus getting a $1.5k central A/C box & having ductwork run, or even better, putting in a Spacepak hi-velocity system.
In my ideal world, I'd have a Mr. Slim in every room, but they don't make them small enough for just a regular bathroom, and their central control stuff still stinks. They really need to add some home automation features, because per-room temperature control is an awesome idea, and they need to make different sizes for different rooms, including smaller rooms. The current wall-mount units are
way too big for the size rooms I have, and for your common American bedroom size. And some of the neater configurations are only available in places like Canada for some reason!
I've had some furnace & A/C glitches over the past month. It would be nice to have a distributed system so that even if one failed, the others would still work, so you could at least move to another part of the house. My A/C was non-functionality for a few days, my ceilings are too low for ceiling fans, and the rooms with all the stuff in them don't really leave room for floor fans, so it got pretty toasty for awhile there. I ended up installing a Honeywell Wifi thermostat, which is pretty nice because the color touchscreen is really intuitive, and the wireless control from my smartphone is nice, but it'd be even cooler to be able to control it per-room...I don't want to heat up or cool down the whole house, just my bedroom in particular, but without having to burn through money using an electric heater or whatever. We're almost there, we just need a few more models - c'mon, Mitsubishi!!