Do I need a 3 zone mini split

[Walkers]

I am building the guest house below. The plan shows a single zone mini split. I just dont think a single zone unit is going to adequately heat or cool the space. I would think a 3 zone unit would be a minimum, one for the great room, one for the bedroom, and one for the bathroom. I am also unclear how many BTUs would be required for this plan. Walls are 12' tall. Framing is 2x6 with spray foam insulation.

 

[Phuckin' Jim]

Hi.
Probably a 2 zone at the most.
Bathrooms traditionally don't have their own zone..
If you can deal with the sleeping area being a couple degrees cooler in the winter than the other areas, a bigger single unit in the great room should work out, especially since the building will be well insulated.

 

[Firebrick43]

I cool/heat 1450' with a single zone Mitsubishi mini split on an ICF house. The side to side action of the louvres distribute the air just fine.

I think 3 zones for a guest house is ridiculous that is less than 1000'. Install a louvered door between the sleeping and great room for privacy if you really actually need it? I never sleep with the bedroom door closed even in a central air house unless I have to sleep in the daytime.

 

[Hobby_Man22]

No just send it to me

 

[PoorUB]

Two zone and maybe a 18,000 BTU, but the bath would be an issue. You could put a transfer fan from the main living area to the bath, something small and slow speed, 50 to 100 CFM perhaps.

As for the bath I suppose you could go with a three zone and the smallest head you can find, but most three head units start at 24,000 BTU which is probably twice of what you need.

Is there anyplace you can hide a small low static air handler connected to a mini split condensing unit? They are not very tall, maybe 12", and 24"x 36" square, but they need access for maintenance and then you would have some duct work to deal with.

https://www.greecomfort.com/our-products/u-match-slim-duct/

 

[Jackfre]

I sold several thousand of the Airshare product from Tjernlund for mini-split applications in small apts, and size wise you are in the ball park. Keep the controls simple. A light switch works well. Depending upon orientation, insulation, etc a 12, 15 or 18 would handle it. Oh, and on the Airshare install, either short cut the door or cut a small thru the wall register to allow the return path to the main area.