Mini split AC?
 

The third floor of our home was finished about 20 years ago. HVAC not tied to bottom floors, they installed a furnace(3rd floor level) with an AC unit at ground level. AC has had a leak, dye not showing up anywhere obvious, so leak may be in wall.

Long story short, considering removing the AC component of furnace, installing Mini split with dual room cooling. Not a huge space, a medium window unit can keep it cool enough in the main space, so assuming BTUs is non issue.

I'm in Ohio, and external unit would be on a north wall that gets real weather.

Any advice/guidance appreciated.

Very easy to install yourself. I recommend the cheaper units that have less bells n whistles (less to break).

Mini splits are the future. I work with many HVAC contractors. That is the consensus.

Do it! No need to cool the entire home when you occupy a portion. For us night time/sleep is when we want it cool (70f) and just our bedroom

I have a Mitsubishi two ton split (a/c only version as I do not need the heat pump option where I live) that kicks ass (laughs at the TexASS heat and humidity).

It has all the bells and whistles imaginable, which I like, and a 20.5 SEER rating.

I chose this brand based on the recommendation from a company that makes an aftermarket a/c controller which I use - the company is called Store it Cold, and they have a very good breakdown of window unit and mini-split quality comparisons based on years of research that they have done (they are always updating it, too).

The only negative is Mitsubishi is about the highest cost option, but in my experience with most things, quality always costs.

I ordered mine from a place called Power Equipment Direct - had never used them before, and although I vetted them as best I could, was nervous due to the money being spent by me, but there were no problems whatsoever and I received everything I ordered in about seven days, via truck/freight (updates and tracking all along the way).

Mitsubishi makes many varieties of the splits, including multi-zone models like you mentioned in your OP.

Same here. Installed a Mitsubishi unit myself a couple weeks back. Relatively easy to do. An HVAC dude can complete the final hi/low connections and charge the system. The Mr. Cool ones come pre charged etc. but there's too much piping to coil up which looks sloppy IMO

We have installed a few but they have all been Lenox with their amazing warranty on parts. My HVAC guys like them, pricey but worth it. He like Mistusbishi too. When I traveles in Asia, that was all they had due to their tall buildings without attics. I noticed all the off brands and yet they all seem to be still working?

Another Mitsubishi fan here , I have installed two in the past 10 years . One in our previous homes detached garage and another in my current man cave garage . Very high quality, whisper quiet and very energy efficient .

There are many brands out there . Do your research and purchase what is locally available and/or supported . I would recommend you purchase with the heat function. Good luck

i wish i had put one in a large room i have as its never as cool as the rest of the house.
but i didnt trust them. the AC guy even asked about one.

we have two at work and they have been fine.

I had a multi-zone 3-Ton system by Daikin installed less than a month ago. If we hadn't opted for the multi-zone option I would have installed it myself.

We don't see the temp extremes other areas do out here in NW Washington, but so far it's been amazing. Each of the bedrooms has an indoor unit, plus one in the main living area. The system is also sized to accommodate the new addition we are starting on.

I'm hoping that we will be able to abandon our old NG furnace with this. System specs say it's good for heat down to -5°, but we shouldn't get anywhere near that around here.

I did the electrical, and if the outdoor unit provides power to the indoor unit with the lineset, it couldn't be easier. You're looking at likely needing a new circuit for power, and to be code compliant it'll need a disconnect at the outdoor unit and an exterior receptacle within 25 feet IIRC.

There was also a code change in the latest update requiring GFCI protection. Last I read, NFPA has pushed that requirement to 2023 because of nuisance tripping issues. I asked my inspector about it, and he told me that WA was likely going to make an exception in our state codes to remove that requirement. YMMV of course, so check your local codes.

In short, I wish I'd done this years ago.

Quick edit to add...
Consider what you may need to do to weatherize the outdoor unit. I think Ohio may need some additional frost protection, but I don't know anything specific about that.

We received a quote to install a 2 zone Mitsubishi mini split (one for the family room (18'x16') and the work shop below it (18'x14') for $6200 after local utility rebate. We are in the mid-Atlantic region. Any negatives to mini splits? Do you find that you were able to throttle back the HVAC for the rest of the house?

Installing this myself is beyond my abilities....when it comes to electricity I am definitely a 200/221 whatever it takes kind of guy.


Thanks.

Mike

Another recommendation for the Mitsubishi. Into my fifth year with the current unit. It just keeps working. yes on throttling back the rest of the house. The heat function works great.

Following this thread. My wife likes the bedroom to be about 65 degrees at night. In the summer we run the AC unit on that end of the house all night. It seems wasteful to keep the AC unit grinding away all night cooling 3000 square feet just to get one room to 65. We got an Ooler bed cooler a few weeks ago. It's doing the job, but it's winter now. Not sure how well it would work in the summer.
Do the one-room units operate on 120VAC?

I just bought a couple Bosch 24,000 btu multizone units for our old split level house. I will install one on one end of house that will power two indoor units in upstairs bedrooms. Other unit will be at middle of house to feed large family room and other upstairs spare bedroom. I am gonna wait until spring to install them. I will do all of install except will have a friend who does HVAC come and pull vacuum and charge lines if needed.

I originally got a quote from a local company for $13.5k to install 1 large 4 zone unit. I then priced a similar unit to do it myself for about $4K at Lowes.

I ended up going with Bosch because a prior coworker now works for Bosch and he got me a smoking deal. I went with two separate smaller outdoor units per advice of a friend who installs these type units. (Install will be easier/simpler with shorter line runs and sizing will likely allow better efficiency.)

I put a 2 ton Mitsubishi in the garage about 12 years ago. It's still running fine. It's a heat pump too so it does well in the mild Texas winter. Not sure if it would work in Ohio tho.

I paid $1800 plus $100 for copper lines and installed myself. I think they've gone up quite a lot since then.

I installed a GREE about a year ago in my Cave. Both AC and heat, love it! I was worried about what I would see on my Electric bill.....maybe 30 bucks a month at the most. Keep it at 70 year round....
The reason I picked GREE is they are super popular in China and my friends there love them.....I paid $1400 for 9000 BTU unit and then $700 for the install. I did most the heavy lifting on the install myself. My HVAC guy said he we would give me a break....less than 3 hours of work for $700...not sure I got a break!

No need for the cooling part here in MI
A reg overhead gas heater does the job. I've had a Hot-Dawg for almost 10 years now.
Along with a dehumidifier in the summer...works great.

Ok, for you self installers. What's the installation like?

Our house is old and poorly insulated, but we've got a heatpump that was built/installed in 1991 that keeps us cool in the summer and mostly warm in the winter.

Downstairs is ~1000sqft. Upstairs is about 500sqft. Downstairs is main/full bath, kitchen, dining, living, and office. Upstairs is 2 bedrooms, tiny half bath and a central room. We currently have a single heat pump with with ducts to all rooms including another room that's going to end up being a closet.

It seems like it would be prohibitively expensive to put units in all of those rooms. Although I guess if I could do the install myself, we might save enough for that. Of course, that would mean a ton of installation.

Because the typical installation finds them rather high in a room, Mini-Splits are far better at cooling than they are at heating, necessitating, for at least two people I know who had them installed in their small office buildings, the use of under-desk space heaters to keep the women folk warm.

_

Installation required a 220v circuit inside and out and a flare tool for the copper lines. Buy or pour a concrete pad for the compressor, drill a hole in the wall for the copper lines, attach the lines, hang the wall unit, open the refrigerant valve and turn it on. You don’t have to pull vacuum on the lines but I did and found a bad connection so good thing I did. I also put power switches inside and out to meet code for maintenance.

If little insulation I’d go up a little in size especially if a living space.

Some info here, too:

https://forums.pelicanparts.com/off-topic-discussions/1122946-window-air-conditioner-mini-split-my-garage.html

Where's that damn thumbs up button?

We need a mini-split sub-forum on Pelican. This topic seems to come up every few months. (light-green font needed) ;)

I guess I'm the odd man on this. We put one in our kitchen and I hate the thing. Always dirty and mildews. I would never buy another one for a home.

You are saying the inside component (the register where the air comes out) gets mildew on it?

Does anything else in your kitchen get mildew on it - or just the register?

I only get mildew in my shower stall and shower curtain. No where else in the house. Easily controlled by a periodic spray of Mold Armor.

Why not run an external copper line? When we replaced our AC units, they had to switch to the "New" Freon, one of the lines installed in the house was too small. They ran a new line and the small portion that would have been visible was installed in a conduit cover.

It's just the inside unit. I had a service call and the guy told me it needs to be cleaned every few months. Oh and it stinks like hell. They spray some kind of deodorizer in it and it helps for a while.
Nothing else in the kitchen has mold/mildew.

Yes Mini-split is the future.

We added one to our Oceanside condo and it transformed the space in summer. Easy install, super efficient, and dead quiet. Once the room is at temp it ramps down speed and energy use so it is only drawing maybe 300w while sleeping at night and the indoor sound level is around 40db. I use a similar inverter technology Midea 8000 BTU window A/C for a project room with similar results. Super quiet and efficient and it cost $350.

OK thanks.

I've never ever heard of that being a problem for anyone who have installed these.

Maybe your unit is somehow faulty?

In any event - I wouldn't castigate the entire concept just because of this one issue you had, especially it being an apparent outlier.

Maybe reach out to the manufacturer?

I installed a MRCOOL DIY unit in my shed. This unit is a heat pump as well. I only run it when I need to go out when its too hot or too cold. It works really well.

The installation process wasn't bad at all. I did everything. The tricky part was definitely connecting the coolant lines and getting them properly torqued. The lines are vacuumed out and sealed. They use special connectors to maximize the that you won't mess it up. All in all, I love the unit. It works great in hot or cold weather and the unit is rated at 20 SEER. It took ~6 hours to do everything. It was >90 degrees out so I was very happy when it started cooling right away.

A normal unit needs a vacuum pump and a little more care. That would put me off now.

Sounds like the inside condensate line is not draining well. Confirm that the unit is installed very level and the drain is not pinched or obstructed. Standing water is the most likely source of the nasty smell.

Went out to the man cave this morning , it was 40 degrees inside . I flipped on the mini split and set the heat at 70 degrees . One hour later at the far end of the garage it was 64 degrees .

This is a 24' x 26' space with 12' ceiling height . Pretty impressive performance I think . In my opinion a 2 ton unit is perfect for this space . That cold concrete floor is like a heat sink . Now that winter is here I am going to leave it on and set it at 61 degrees which is the lowest heat setting for this model .

I wonder if installing some kind of timer would make sense for your situation, Rick.

Similar to how one uses them for water heaters.

Guess you'd have to formulate some kind of schedule that meshes with your needs.

Or....because it is so efficient....maybe this is a non-issue....and leaving it at 61 is actually the ideal situation.

Just thinking out loud.....

^^^ Baz because of efficiency I don't mind running it at the low setting . It just doesn't consume that much electricity . Being retired I randomly go out to the garage when I want to . A timer would be a waste . But I appreciate the thought and Happy Thanksgiving 😁

Once it reaches set temp it rolls back energy usage to simply maintain at maybe 200w instead of 1500w at full power. This may be the most efficient way to keep the garage useable.

A very different beast from a ceramic or gas heater that cycles on and off at full power to maintain the set temp.

I cleaned mine for the first time this year. About 11 years over due. I removed the housing and brushed and vacuumed the fins and wiped everything else I could get to. I can see how the tape on bag to capture spray on cleaner and water spray would make for a better job.

My Daikin's minimum setting is like 68F, IIRC. LOL...

A tad cozy for the garage (plus it'll never get there if its low teens outside, so will just run 24/7); in winter only really concerned about pipes freezing - this isn't my living room. I'm also good with turning the heat on manually if I'm going out there...

Interfaced to the mini-split via a CoolPlug/CoolLinkHub unit from CoolAutomation. Had to add the Daikin add-in board (cheap enough on Flea Bay).

Result: I could control the mini-split directly from a web/phone app (CoolRemote). Which had the same stupidly high minimum settings (corresponding to the built-ins for the mini-split, I suspect).

The last piece was to integrate to a Nest (provides all kinds of smarts and/or scheduling I don't actually use/need). And then run that in ECO mode.

So now the mini-split sits idle when not needed - and "wakes up" when temps drop below 40F or rise above 85F inside the garage. Or exceed specified "emergency" temperatures, regardless of schedule/user settings on the Nest (eg override "OFF" setting if temps drop below 35F).

The integration stuff was not cheap. However, the end result is not running heat 24/7 when it's above freezing outside, "warm enough" inside - or neglecting to turn it on when there's a cold snap. So pretty much feels like a win. Also nice to check remote Nest sensors from your phone when it gets into the low teens outside...