How many rooms can a Mini-Split handle. (1 Viewer)

[Spike Strip]

Howdy All,

I've got a small house ~ 1000 sq ft. And live in So Cal where it's easily over 100 F during the long summer.

I currently have a roof-top Carrier, but at 25 years old, it's time for a replacement. I hate the roof unit, but it was installed by the PO of the house.

I'd like to install a Mini split, but really don't know much about them. Can one condenser be used with multiple evaporators? In my case, I'd probably need 3, for the house as it's a 2 bd 1 ba with kitchen, living room ... I'd like to my research done so I can get a contractor lined up for Spring, or earlier, during their off-season.

Also, I'll most likely go with a high-end Mitsubishi or Fujitsu

Thanks!

 

[LSUfj]

Pretty sure you can get some condensers that will support up to 6 air handlers. You could probably get by with one of the 3x9000btu units. Be sure to get a heat pump so you can use it when you need heat as well. Here’s an example, although not one of the higher end brands.

28000 BTU Tri-Zone Mini Split Air Conditioner - Heat Pump - SENA/30HF/T

The Senville 28000 BTU Tri-Zone Mini Split Air Conditioner is Energy Star Certified, eligible for tax credit, with advanced features like Alexa control and Ultra-High Efficiency Inverter technology.

senville.com

 

[bkfj40]

The other item that will help you is insulation. How much do you have in the walls and ceiling?

I’d look at putting in a HRV in the kitchen and pump fresh air into a bedroom. This will help with the fresh air needs that the split units don’t provide.

 

[Spike Strip]

I'm unfamiliar with HRVs -. Will have to do some research. Thanks

 

[WarDamnEagle]

Why don't you just get some quotes from a couple of HVAC contractors? I'm sure they know what various systems will do and if you get more than one proposal then you can compare and begin to see who you feel comfortable with using.

 

[Spike Strip]

Yes, going thru the process now.

 

[sogafarm]

I've gone through three mini-split systems in the last 10 years so here is my suggestion. Go with the Trane/Mitsubishi mini split from a well established installer/dealer. They are more expensive than the cheaper companies but parts and service is available throughout the U.S. The unit is extremely efficient and is a great de-humidifier. The heating is ok for the deep south. I use less than 300kw per month total, so my bill during the summer high heat months is usually less than $45 per month. Less in the fall and spring as I like to open up the cabin during the milder months.

So here is the story....
When I built my little efficiency cabin (600 sf or 24x24') with a modified open platform I wanted it to be energy conserving and cheap to maintain temp. Since I was building it myself and on the cheap(price, not quality) I originally went with a chinese brand mini split with one outside compressor and two 9000k btu indoor units, one in the living area and one in the bedroom. I installed it myself with the final wiring done by a Hvac pro friend. After only 10 months it stopped working because a mouse short circuited the control board on the outside unit making it inoperable. After several attempts at fixing it and having no available parts or dealers, I gave up on it($2k down the drain).

I used a window unit temporarily for a year+ until I could save up enough for a Mitsubishi single 12k unit installed by a local Hvac dealer using the existing lines($2400). It worked great for about three years, then I had to have the freon topped up about twice a year. There was corrosion on the inside unit that caused a leak. When I contacted the installing dealer, he said he had moved his business to south Fla(Damn it) so I was SOL.

The window unit came out again until I could afford a new unit. This time I went with a popular local dealer called Safe Air and the same but newer Mitsubishi/(now)Trane unit installed with new lines had gone up to $4200(Argggh!). This is the current set up still running at less than two years old. I'm noticing that it's not as great at cooling and heating as it was last year, so it's time to have them top it off with more freon. The good news is the Safe Air company is still in business and the unit is under warranty(2 yr parts/labor, 7 yr parts only, and 10 yr on compressor) still. I just need to schedule an appointment before next summer to top it off and inspect.

Moral of the story, go with reputable company with good warranty program. Don't expect great longevity, but do expect good climate control and low Kw used. Hope this helps and I would suggest these units as an alternative to traditional for a small home just don't skimp on the dealer. Good luck!

 

[Spike Strip]

Thank you for that info - I have requested a Mitsubishi unit in all estimates. I'd rather pay once since I don't feel like doing the install myself, and rather have a pro who knows the tricks and what works.

I've budgeted about $5K for this as I will have to have the existing Roof-Top unit removed (gawd, I hate those things) and some of the holes patched/repaired and existing ducting removed to reclaim some attic access and space.

My house is an unimproved 1949 build and there is no wall insulation although I did have Cellulose blown in the attic and powered attic vents installed some years ago.

I was asking for a Heavy Duty 15,000 BTU unit, something like this:

(do all of these have a heat pump?)

Just doing my research before pulling the trigger and appreciate all the real-world experience MUD folks can share!

 

[sogafarm]

Not all are heat pumps, some are just AC. Should indicate on the website. If you've got no insulation in your walls, I would highly recommend have them foamed for the most efficiency, but costly. If you've got closed rooms to cool then you will have to have a seperate indoor unit for each sealed room. If it's an open floor plan then a larger single unit can be used. Good questions for your Hvac dealer.

Thank you for that info - I have requested a Mitsubishi unit in all estimates. I'd rather pay once since I don't feel like doing the install myself, and rather have a pro who knows the tricks and what works.

I've budgeted about $5K for this as I will have to have the existing Roof-Top unit removed (gawd, I hate those things) and some of the holes patched/repaired and existing ducting removed to reclaim some attic access and space.

My house is an unimproved 1949 build and there is no wall insulation although I did have Cellulose blown in the attic and powered attic vents installed some years ago.

I was asking for a Heavy Duty 15,000 BTU unit, something like this:

(do all of these have a heat pump?)

Just doing my research before pulling the trigger and appreciate all the real-world experience MUD folks can share!

 

[sogafarm]

On another note, one of the best advantages of the minisplits is the de-humidifier. If you experience humid summers where you are, then this will be a great asset. My wood floor boards will slightly shrink and have small gaps after the unit is operating for a few days in Dry mode. They swell back up when I open up. That may just be a deep south humidity thing though.

After deleting the second unit in my cabin, I deleted the wall between my BR and the LR to help with circulation and it works great as a mainly open floor plan, only one indoor unit needed.