I'm don't really know too much about ac stuff, however I'm in the market to replace a heat pump in my casita. My neighbor actually recommended a Mr. Slim. We are in Las Vegas (very, very hot summers) Anyways she had one installed in her garage and she said she loves it, cool in the summer and warm in the winter, and she is a very hard to please consumer. Just an FYI.

My father-in-law just installed one in his 320 sq foot bar/rec room (it was added as an afterthought to his new home and didn't have any air ducts). It has 4 sets of French doors and regular fiberglass insulation. He loves the Mr Slim -- quiet and it seems to cool the space quickly. He lives in New Orleans, if that tells you anything.

There are several mini split systems on the market similar to Mitsubishi's Mr. Slim. It being the first one I installed however, I have to admit I was impressed.
Drawback is the refrigerant and condensate lines running to a second story. But there are chase moldings available to encase them that don't look that bad.
The evaporator on the wall inside isn't bad looking either and unbelievably quiet. Systems come with a wireless remote for operation. A little pricey, but perfect for difficult areas such as you're describing. You will also need an installation convenient location for the outdoor unit, 110 line voltage for the evaporator inside and 220 l.v. to the outdoor section.
Also available are evaporators that are ceiling suspendable or mount flush in the ceiling itself: models PC or PL respectively.

Mr Slim is a great product would look at 1 ton system could expect to pay a contractor 2,800 to 3,500 there are other brands on the market but there reliability doesnt compare.

We just a got a quote of 4250 for a 9000btu mr. Slim. They said the electrician is 450 extra and is included. Seems so super high to me. Any thoughts? Thanks!

Anders:

Not knowing all the variables to your installation there might be a reason for the very high price. I recently had a 15,000 btu Fujitsu RLQ Heatpump (20 SEER and qualified for rebate) installed for $2700. This price included running a new 220 line from the electrical panel to the new condenser location (50'). In our area (South Carolina) Fujitsu is a popular brand with installers along with Mitsubishi. As mentioned in a previous thread Mitsubishi was the first company to introduce these in the USA and is the most widely known by name.

I also got bids from 4 other contractors including two who specified the Mitsubishi 15000 btu heatpumps. From my web searches and discussion with HVAC folks it would appear there's not much difference between the top of the line brands. The prices varied greatly between quotes even for the same product although the Mitsubishi lowest quote was $500 higher than my low Fujitsu quote.

I would suggest going with an installer certified by the manufacturer and who has installed a large number of these units. Get at least 3 quotes. Also make sure it's an inverter operation with high SEER.

We love our mini split. It's doing a great job in our 400 s.f. sunporch.

Good luck.

Having just spent most of the day working in a communications room with a Mr.Slim make sure you hear one before deciding.

It is better than a window unit, but worse than central air for noise.

As for the noise level, I would say better than some mediocre central air systems, better than most poor and noisier than excellent central systems.

I am getting ready to install a MR Slim 3 zone system. I have been researching differant systems for 2 years while getting other work including more insulation installed done. I have been in rooms with the H2i Hyper heat system in them and you have to put your hand up to them to tell that they are on they were so quite, I am putting 1 12000 BTU H2i in the Living room and kitchen area, then 2 other units H2i 9000 Btu 1 each on the opposite ends of my home. ( fully remodeled Manufactured house) The price for this is 7500$ and I will run the 220 volt lines to the Compressors. The Mr Slim uses 24 volts from the main compressor to run the inside units unlike what one poster said about having 120 outlet inside. I live about 100 miles NW of the Washington DC area and these units will put out 100 percent of their heating at 5 degrees 85 percent at -5 which makes them Ideal for this area. I had 5 Est. on differant system's anywhere from 3500 using my oil furnace with a heat pump add on to 15000 for the same Mr slim quoted above, so it pays to shop around and do your homework. I will be able to do away with my oil furnace giving me 3 more feet of kitchen counter space which is greatly needed.

Had a Mr. Slim put in our Carriage House 4 years ago. This summer, it began dripping on the inside and caused water damage in the house. I thought it just needed to be professionally cleaned. Nope. There's something going on inside the unit behind the condensate pan that causes condensation to flow behind the pan and run out the bottom. Searches online show that one should be prepared for inside condensation leaks and the unit is best located where water dripping from the unit won't cause damage. Learned the hard way. Ruined an Ethan Allen chest of drawers, drywall and carpet. Now the unit has to be pulled, taken to a bench and dismantled before I can learn the full extent of what this is going to cost me.