Can someone help me size a mini-split heat pump

[JimRB]

I would bet that a smaller unit will do a better job of dehumidifying in the summer. I have a 3 ton unit conditioning 2700 sf in Atlanta. It does a fine job. It is technically a wee bit bigger than what the EMC calculated for the house.

 

[harleyboyer]

I also need to find out what size mini split to put in my sun room. I have a 300 square foot all glass sun with 10 foot glass roof. I live in nashville TN so heating is not a problem, it has full sun from noon till the sun goes down. I'm thinking I need an 18,000 btu, a guy I work with says a 12,000 would be fine. can anybody help.

I have a 450 square foot studio with 8 foot ceilings over top of my garage. Since it's a studio I have two layers of 1/2 drywall over resilient channel. It is well insulated and only has two small windows and a door. I am looking at the Mitsubishi Mr Slim 21 Seer heat pump system. I hope someone can tell me if I should by a 9000 btu or the 12000 btu system. I have heard that it's better to undersize a little but I don't know if 9000 btu's is too undersized. I live in eastern Ky if that helps. If someone out there has installed one of these can you also tell me what size wire I will need to run this system. I have a 10/3 wire with nothing on it near where I am installing it if that would work. I like the design of the LG Art Cool system but I have read some complaints about the LG systems. I appreciate any advice I can get.

 

[kenmac]

Hard for me to know (from behind a computer screen) how much heat gain you have in that room. I will be glad to give you my best guess and say 18000 BTU should be plenty for 300 SQ.12K may also work. Just depends on your heat gain

 

[Alan L.]

I'd go with 12,000 on that space. I have never regretted 1 BTU of air conditioning that I ever put in. I have a 3 ton on 850 square feet of living quarters in shop. Lived in it for 7 years and was glad to have it. We have moderate humidity, more in the spring, but most of the time in Texas we need the cooling capacity. If you live in an extremely humid area it might be different, but even then I think you would be disappointed with the 9,000.