Ductless mini split AC heat

[DonNOhio]

Anyone have experience with this system? I am thinking about one for my shop. Been looking at a Mr. Cool as it is a DIY system. Every thing is pre-charged. I wouldn't be using it in the dead of winter when it is below 40 or so.

 

[john in la]

No experience yet but I have a 9k unit that will be here Thursday. Going to use it Im my master bedroom to replace a window unit that supplements my central unit.

A guy at work has a double head unit in a portable work shed. He loves it.

 

[KD Cannon]

We have two Mitsubishi mini splits units for our home. Excellent performance and are very cost effective. Important to keep after the filters clean, wash them out in the sink, dry and put back in inside head units. Had for over six years with zero issue, just keep outside unit fins and inside units filters clean for best performance.

This post was edited by KD Cannon on 04/26/2022 at 05:06 pm.

 

[Dopp Creek]

I have an oil furnace so I installed a Daikin mini-split system five years ago for A/C. I have a three ton condensor and four air heads throughout the house (2100 ft ranch style). It is quiet and very efficient. We even use it for heat unless it is below 35 degrees. We are very happy with it.

 

[Keith True]

I've placed dozens of those things with a guy that does them for a living.He says the biggest problems are from the owners.They have their place,and work well in it,but some expect too much out of them.They need to operate in an insulated environment.They are meant to maintain temp,they are NOT a space heater to turn on and off at will to warm up a cold shop.I know of a couple being used that way,the owners grumble a little bit,but they were warned,but didn't want to listen to the installer.I'm installing a 3 head unit right now,one 18000 BTU head,and and two 9000's.It's a 3 ton,or 36000 btu unit.

 

[Gambles]

Ive helped install several dozen. Get one that is also a heat pump and the you CAN use it when it gets below 40 degrees. The local high school had about 25 of them installed about two years ago to be both the AC and heat. When it gets below 10 degrees, the old boiler kicks in to help heat. Currently, no mini-splits are made in USA, so just get one with the best warranty.

 

[Bob Harvey]

They will work in below temps, but your Hydro meter may burn out it's bearings. How do I know ? The are labeled 'Air Conditioners'

 

[Russ from MN]

We have friends here in MN that have them and like them. We have a natural gas furnace with central air so it's not something we need.

 

[woodbutcher]

I've had a couple of them. The first was a Fujitsu that worked well for about 15 years. When a control panel went bad we couldn't find anybody who could work on it and we couldn't buy parts, so we bought a new system. It came with three badges- American Standard, Traan, and one I don't remember. When I searched the internet for a manual, it turned out to be made by a Korean company- Gree or Ghee. It worked well.

Butch

 

[MarkB_MI]

I installed a Mitsubishi mini-split in our house about ten years ago and we've been happy with it. It's very quiet and efficient. Our house has hot water baseboard heat, so there's no ducting for central air and it would be nearly impossible to retrofit ducting. I don't know how practical a ductless system would be in a shop, but I've seen them used in fairly large restaurants. Just like any AC system, it needs to have sufficient BTU/hr capacity to cool the space.

I did discover after several years of use that the inside units need to be cleaned yearly to remove mildew. Ours got weaker and weaker until I had to have a service tech come in, partially dismantle the units and clean them. You can buy funnel contraptions that you attach below the units so you can flush them out with cleaning solution. I need to remember to do that this year.

We've never tried to heat our home with the ductless system, even though it has heat capability. As far as I know, none of the ductless systems have auxiliary heat, so they're not going to be very effective or efficient in cold climates.

You say Mr. Cool is DIY. Actually, you can install any of the systems yourself if you can get someone to sell you a system and if you have a good vacuum pump. I installed our Mitsubishi system. The outdoor unit comes pre-charged; after you hook everything up and pull a vacuum, you open valves on the outdoor unit and it's good to go. It looks like Mr. Cool uses pre-charged linesets, so you don't need to pull a vacuum. The downside of the pre-charged linesets is you won't be able to cut them to length.

 

[DonNOhio]

Thanks for all the info. Food for thought.

 

[Geo-TH,In]

Better ask what it costs to have mold removed annually.
I can't remember the exact amount, but a HVAC owner says it costs about $200 per unit. 2 hours at $100. He uses moldstat. Says they have to remove the squirrel cage.

The design of the wall unit is similar to a window AC and costs a lot more...

 

[Stroby]

I don't know how big your shop is or how it is insulated, but, I have a 600 sq ft woodworking shop, with 6 insulation in the walls and 10 in the ceiling, concrete floor. I use a de-humidifier in it and it is quite comfortable most all summer. BTW, I live in good ole Illinois, the worst state in the union.

 

[MarkB_MI]

> Better ask what it costs to have mold removed annually. I can't remember the exact amount, but a HVAC owner says it costs about $200 per unit. 2 hours at $100. He uses moldstat. Says they have to remove the squirrel cage.

Yes, it cost around 400 bucks to clean our two units, but that was after several years of neglect. Had I known, I would have done annual cleaning with a bleach solution. Here's an example of the cleaning kit you need; there are cheaper versions on Amazon and eBay.
Mini split cleaning kit

 

[WNYBill]

They are not cheap! But work well and are QUIET! Much quieter and more efficient than a window AC. If you live in the north, get the mini split with a heat pump, so you have heat also. Ours will heat when it is 20 below 0, but is not efficient below 0. You can buy pre-charged kits for DIY.

 

[1948CaseVAI]

Look at youtube from Abom79 - he has several Mr Cool units and his videos show installation in detail. He had one older video of install in his own shop and about three weeks ago made a couple of new videos when he installed three units in his new shop. They seem to work great. As long as you have available electric you do not need any other trades to be involved. If you do your own electric you are truly all set.

 

[John T]

I have no experience using them but Ive seen several RV owners ditch their traditional rooftop units, go mini split and they all brag how well they work and are more efficient they claim ??

John T

 

[old]

Don't know if it would be called ductless but right now we are using a unit that has 2 hoses that go out a window to cool my moms house till the part come in for her heat pump

 

[DoubleO7]

Can't possibly be as loud as a Dometic roof top rv unit !!

 

[John T]

AMEN to that, they are MUCH quieter

John T

 

[Keith True]

All the ones I've been involved with have a heat pump also.They are dead quiet,nothing like an air conditioner.We put a three head unit in for an old woman,on the air alone she said her power bill ran $125.per month less in the summer with her new units..She had been using 4 window units,and was mostly scared of overloading her old wiring.On one brand unit we installed the manufacturer asked if we knew how may feet of line we would be using.We knew,and told him.For the short run we were using he said he could overcharge the unit with the small amount required by the lines.Took a vacuum on it,opened the valves,and it was perfect.

 

[Geo-TH,In]

Mark
I bought my house in 1977. It had a central AC.
Unlike most homes, my house had an air return in every room so you can close a bedroom room and temp remains constant.
Guess how many times I've had to sanitize my AC?? ZERO
I replaced the central 24 years, still working fine..

Many HVAC companies that sell split units also sell maintenance contracts. $200 per unit. 3 units $600 a year.
It's your money. I don't see the advantage of a split unit.

I would recommend using a central unless you have a slab home.

 

[DoubleO7]

How come you exclude central for a slab home?
Most slab homes here have been built with central.

 

[MarkB_MI]

> I would recommend using a central unless you have a slab home.

Running ductwork is a non-starter in our quad-level house heated by hot water baseboards. Ductless is a cost-effective solution. The only other option that might work would be a high-velocity central air system, which uses 3-1/2 diameter ducts that can be run between wall studs. Those systems are quite expensive.