Mini Split A/C systems

[Bocephous]

When I read installation cost of $3300 and compare price for a 15K window unit, about $500, I wonder how long one would have to run it with electricity cost like mine, 10 cents/KwH, to save money.
For $2K I can buy a lot of electricity.

I struggled with the idea of paying that much for a couple of years. I shopped around and found the best deal, installed by a local HVAC professional I went to school with.

Our unit also provides heat; we burn wood/coal, so this will help us out in the shoulder seasons (I keep our fire going 24/7) and on the coldest nights (heats to -15F).

Babysitting our stove for one or two fewer months a year is worth something to me, as is not installing the huge 12K BTU window unit with the homemade window frame and taking it out every year.

Also, I can't hear the inside unit running unless I am standing right below it or turn the fan on high, and the outside unit I can't hear at all.

If it really lowers our electric bill (compared to a window unit and the supplemental baseboard electric heaters the home was built with) significantly I may eventually look into having another unit installed in our basement, mainly to dehumidify and keep our pipes from freezing if we choose to travel in the winter after I retire in 5 years, God-willing.

 

[Jlblake]

So from my perspective it sounds like you are getting solid advice and the pricing seems fair.

Thank you!

 

[Jlblake]

Thanks everyone. Very helpful comments and I appreciate your help!

 

[IXLR8]

I had a Mitsubishi Mr. Slim installed in our house. One 12K BTU unit handles the kitchen, dining room, living room and bathroom. I use it for heating in the shoulder seasons, cooling/dehumidifying in the summer. I find it costs me about $0.50/day in the summer for cooling and about $1.00/day for heating in the shoulder seasons. It cost about $3200 to have it installed, a government rebate then reduced the cost by 30%. To have a cool home in the summer and quiet heat in the shoulder seasons without running the baseboard electric heaters or fighting with the wood stove to not cook us out, it was worth the cost to me. I listed to window AC units growing up... I will gladly pay extra to not have to listen to that noise.

 

[IXLR8]

In every case, when I walk into those homes, or those rooms, they feel more humid and uncomfortable compared to more traditional AC homes. They are better then nothing, and maybe cheaper to run than a window unit, but if I wanted to make a room comfortable and didn't want to, or have the option of running ducts, I would rather have a window unit. Granted, they are ugly, noisy and suck up electricity, but they work great at cooling off a room.

Sounds like the Mini Splits were not sized correctly, which also happens with a 'traditional' AC home unit. My home is very comfortable with the Mini Split, presently outside humidity is 95% and inside it is 68% according to my Davis weather station.

 

[LouNY]

Sounds like the Mini Splits were not sized correctly, which also happens with a 'traditional' AC home unit. My home is very comfortable with the Mini Split, presently outside humidity is 95% and inside it is 68% according to my Davis weather station.

As is mine presently outside temperature is 77F and 80% humidity,
the inside is 70F and 49% humidity at 8:30 PM

 

[riptides]

Another option is the wearable system. Much cheaper to own, operate and personalized!

This Wearable Air Conditioner Provides 2.5 Hours of Cooling - Nerdist

 

[JethroB]

I had good results with the two mini-split systems in our two server rooms at work. Very quiet and dependable. I wanted to install one in my small weekend cabin but didn’t have available wall space for the indoor unit so I went with a hotel type unit called a PTAC. It gets the job done but would have much preferred the much quieter mini-split.

 

[fatjay]

I paid $1000 for my 24k btu mini split on ebay, another $200 for materials to install such as a poured concrete slab, 3.5" masonary hole saw, 12-3 wire, fuse panel, vacuum, and set of gauges. Install was roughly 4 hours, and most of that was spent drilling through block, either the 3" or the electrical. It came precharged with the lines cut to length. Never did anything like it before, watched a couple youtube videos, and everything came out great. It's keeping my wife comfortable at 71F through the whole first floor for the second year in a row.

 

[Mallard1]

I just put a Mr. Cool DIY mini split in the two back rooms of my shop. One is a 400 sq ft studio for my wife with the south and east wall almost all glass. I used a 18k btu there. In my room next to it (200 sq/ft). I used a 9k btu as that was the smallest they had. both of these feed off of a 27k btu outdoor unit. It was not to difficult to install. I mounted unistrut on the outside and placed the L brackets on it and set the outside unit there. Had to run a 220 30 amp circuit out there and a 30 amp disconnect. The inside units come with a cardboard cutout to tape to the wall that you can mark the mounting holes and the hole for the lines to pass through. I then mounted the brackets and snapped the unit onto the wall with only the short stub lines being passed though. then i hooked the line sets to the unit stubs and ran them to the outdoor unit and hooked them up. The DIY series do not require being vacuumed down as the lines and unit are sealed. after everything is hooked up you simply open the valves and turn on the power. Total install time was probably 6 -8 hours having never done this before. I believe I could do the next another one this weekend in 4 hours especially if I had a helper. the cost of my inside and outside units was 3k. I could have gotten by cheaper if I had done 2 outside units but I wanted one larger one.

after 2 full days I really like them so far. they are very quite and other than when they were both turned on and trying to cool down the rooms from 90 degrees the outside unit seems to stay on a low setting. they both made a ton of water initially but now not two much. I am going to have to install a pump for the 18k unit as the horizontal run is to far and must have a slight up hill run so the the water wouldn't flow. I just have it draining into a 5 gallon bucket until the pump arrives wednesday. It has made two inches of water in a 5 gal bucket in 24 hours.

 

[dstig1]

I have been considering something like this for my shop. Right now I just use a dehumidifier, which helps knock down the humidity, but when we have extended hot stretches, like now, it still gets pretty hot in there. Looking up the MrCool website, I see they have zero information on how to size a unit for a building. Does anyone have a reference? I'm hoping there is something simpler out there than a full Manual J analysis...

 

[Jlblake]

my units are supposed to arrive today. Installation takes place Thursday and Friday. Looking forward to having this project off my list and having quiet, cool air upstairs!

 

[Jlblake]

On another note, we spend most of our time (almost all of it) downstairs. Upstairs is incredibly hot. Would it be more efficient to set the new units to hold a certain temperature or better to only turn them on when we plan to use the upstairs? Right now, the cool air doesn't seem to go upstairs at all. Seems like we should only use the new units if we're going to spend time upstairs since it appears the downstairs unit isn't losing too much energy to the upstairs...but, I know nothing about air conditioning.

 

[Jlblake]

A/C guy let me know that the manufacture sent a 22 seer unit rather than an 18...same price. I got all excited. I ran a calculator and estimated that I'll save $52 per year. $52 is $52, I'll take it. Just not quite the savings I expected.

 

[milkman636]

On another note, we spend most of our time (almost all of it) downstairs. Upstairs is incredibly hot. Would it be more efficient to set the new units to hold a certain temperature or better to only turn them on when we plan to use the upstairs? Right now, the cool air doesn't seem to go upstairs at all. Seems like we should only use the new units if we're going to spend time upstairs since it appears the downstairs unit isn't losing too much energy to the upstairs...but, I know nothing about air conditioning.

Well, now that you’ve had them for a few weeks, what do you think of them? I know it a little late to answer your question, but my recommendation would by to keep them in cooling mode at a higher set point than your downstairs. That will keep the spaces tempered and dehumidified a little. That’ll probably take a little load off your downstairs unit, and it’ll hit your desired set point faster when you do use the space.

 

[Jlblake]

Well, now that you’ve had them for a few weeks, what do you think of them? I know it a little late to answer your question, but my recommendation would by to keep them in cooling mode at a higher set point than your downstairs. That will keep the spaces tempered and dehumidified a little. That’ll probably take a little load off your downstairs unit, and it’ll hit your desired set point faster when you do use the space.

So far so good. They seem to take a little longer to get everything cooled off but they work well and they are quiet. I keep them set at 80 which does seem to help. I'm happy with the decision at this point! Thanks for asking.