Mini Split A/C systems

[Jlblake]

Good morning everyone!

Have any of you installed mini-split, ductless a/c systems?

The home I recently bought has had the attic converted to living space. The upstairs is around 850 square feet. The previous owner has one (old) window unit to cool the area. I don't like window units and I want the windows closed/sealed up. The A/C guy that came out last week crawled under the home (pier & beam of course) and showed me that the current duct work is not accessible to the rear of the home. His suggestion was a mini-split system...two of them actually...one for the bedroom and one for the office area upstairs.

Ductless Mini-Split Systems - AC & Heating | AlpineHomeAir.com

Do any of you know much about these? Total cost for installation, some new required electrical work is around $4k. That's 12k in one room and 9k in the other...seer rating is 19/18.

Thank you!

 

[TnAndy]

I have two of them in my house, both self installed, love them Very quiet, electrically stingy, great units.

Biggest issue is running/hiding the line sets/drain. One of mine I ran across an attic space, the other comes thru a basement wall and up inside a closet wall, the unit is over the top of the closet doors facing out into the bedroom. I have another unit bought waiting on a bathroom remodel this fall, while the bathroom wall is gutted, I'll run the lines up that wall to the bedroom over the 1st floor bath.

You can do much better on the SEER rating than 18/19. The Mitsubishi 12k unit in my bedroom is 23 SEER.

 

[Jlblake]

I have two of them in my house, both self installed, love them Very quiet, electrically stingy, great units.

Biggest issue is running/hiding the line sets/drain. One of mine I ran across an attic space, the other comes thru a basement wall and up inside a closet wall, the unit is over the top of the closet doors facing out into the bedroom. I have another unit bought waiting on a bathroom remodel this fall, while the bathroom wall is gutted, I'll run the lines up that wall to the bedroom over the 1st floor bath.

You can do much better on the SEER rating than 18/19. The Mitsubishi 12k unit in my bedroom is 23 SEER.

Thanks for the insight.

 

[dalola]

I can't offer you much detail, other than a friend who has one in his office (it's a separate garage-type structure on his property), and is very happy with it. The few times I've been in, you can barely hear it run, and it's always a comfortable temp inside.

In the right situation, I would give it a good look for sure.

 

[LouNY]

A couple of years ago I had two large mini-splits installed in my home.
There are two 36,000 BTU out door units each of those feeds four independent heads through out the house.
The installers had to work a little as all the lines enter the basement then travel to beneath a closet then up to interior walls in the house.
The cost was actually more then installing a central air unit would have been but of all the contractors that came out every single one wanted to put every thing in the attic and just run flex ducts to the individual rooms with a single thermostat for the entire house. In this air it gets very humid when it's hot and too many people I knew had moisture (condensation) issues with the flex duct in the attic.

None of them wanted to talk about individual room t-stats and powered dampeners so different areas could be set different, or even not be air conditioned if not in use.
Then a couple had the audacity to complain when I didn't pick there system because it was cheaper.

My electric bill has gone down for the summer with several window units replaced by these two large multi-splits,
and they do a decent job of heating in the fall when the temperture swing a lot day to day or week.

 

[3Ts]

We have an 805 sq ft cabin that we built and lived in for a couple years. It is much better insulated than normal for this area so I did all the BTU calculations and the installation with some help from my wife. The hardest thing to do is to get the indoor unit up on the wall while sticking the stub lines thru a 3" hole. (We were in our mid 60's at the time). You'll need to run power to the outside unit. The power for the inside comes from the outside unit and can run in the same chase as the refrigerant lines. We bought our unit on-line from Supply House. I can recommend them, they've done well for me.

The most important thing is to draw the vacuum below 300 microns! Use a small vacuum pump and a digital pressure gauge. Plan on running the pump all day. Even if the vacuum drops below 300 after an hour, keep the vacuum on it all day. In this case, slow is better. If your lineset is more or less than 25' you'll need to adjust the amount of freon. I made sure to use exactly 25'. It has been running almost 6 years now and the only repair has been a fan bearing on the inside unit that was getting noisy. As for maintenance, it's been trouble free although getting to the filters at the top of the inside unit requires a short ladder for us. Think about how you'll get to it for maintenance, we installed ours over the washer & dryer so we have to move those out to get to the A/C inside unit.

 

[ustmd]

Like you, I am in Central TX and did an attic conversion. I put in a mini spilt and love it. If I did not already have a traditional duct system in the rest of the house, I would convert everything to it.

The system is quiet, effective and cheap to run. $4K installed for 2 systems is not bad.

There are Mr Cool units that are DIY systems with lines that are already evacuated. The New MRCOOL DIY Is Engineered For Comfort

 

[Jlblake]

We have an 805 sq ft cabin that we built and lived in for a couple years. It is much better insulated than normal for this area so I did all the BTU calculations and the installation with some help from my wife. The hardest thing to do is to get the indoor unit up on the wall while sticking the stub lines thru a 3" hole. (We were in our mid 60's at the time). You'll need to run power to the outside unit. The power for the inside comes from the outside unit and can run in the same chase as the refrigerant lines. We bought our unit on-line from Supply House. I can recommend them, they've done well for me.

The most important thing is to draw the vacuum below 300 microns! Use a small vacuum pump and a digital pressure gauge. Plan on running the pump all day. Even if the vacuum drops below 300 after an hour, keep the vacuum on it all day. In this case, slow is better. If your lineset is more or less than 25' you'll need to adjust the amount of freon. I made sure to use exactly 25'. It has been running almost 6 years now and the only repair has been a fan bearing on the inside unit that was getting noisy. As for maintenance, it's been trouble free although getting to the filters at the top of the inside unit requires a short ladder for us. Think about how you'll get to it for maintenance, we installed ours over the washer & dryer so we have to move those out to get to the A/C inside unit.

Thank you, great information. I have an HVAC guy installing it.

 

[Jlblake]

Like you, I am in Central TX and did an attic conversion. I put in a mini spilt and love it. If I did not already have a traditional duct system in the rest of the house, I would convert everything to it.

The system is quiet, effective and cheap to run. $4K installed for 2 systems is not bad.

There are Mr Cool units that are DIY systems with lines that are already evacuated. The New MRCOOL DIY Is Engineered For Comfort

Thanks. Great to know yours has worked out well.

 

[Lineman North Florida]

I built an 800 square foot hunting camp and installed an 18k Mr Cool DIY unit myself and it has been fantastic , I have less than $1500.00 in everything and it was pretty simple to install , I would have never believed how quiet and energy efficient they are , I don't think you will be disappointed.