I need a good Mini Split - 12.3k btu calculated heat load

[Designer_82]

I did a detailed heat load calc in Carrier HAP program and came out to 12.3k btu.

two questions-
1. Would you go with a 15k btu mini split or a 10k? (I'm thinking 15k to be safe)
2. Can you recommend a good one for me please? (Cooling only, don't need heat)

It will be two zones, zone 1 is 315 cfm 6.8 mbh, zone 2 is 255 cfm 5.5 mbh.


Thank you

 

[CodyK]

What is the application (residential, business, etc.)? How often will it run? Slightly oversizing to a 15k btu wouldn't be a bad idea if it was for a space that isn't used often as it will cool down quickly when you decide to use the space. However, if the calculations are calling for a 12k cooling load, I would use a 12 k mini split. The 15k system won't hurt anything because of the inverter, but a 12k can go up to 13k (per the article below) so you would be paying for something you don't need.

https://www.contractormag.com/hydro...tems-dont-oversize-choose-the-right-equipment

 

[willard3]

Oversizing cooling equipment may lead to problems with space wet bulb temperatures.

 

[EnergyProfessional]

Your title says heating load, but you say cooling load?

Look at the Mitsubishi mini-split. The nominal 1-ton units are rated to modulate 3,000-15,000 Btu (which is more than 1 ton). Maybe ask Mitsubishi about the use above the nominal 1-ton if that applies to your ambient conditions.

You have to judge how you assumed the 12.3 kbtu and how that presents actual usage. I would use a unit at least that size that can modulate. I wouldn't want to downsize.
Like did you use the 99% cooling temp, 99.6% etc.?

 

[Designer_82]

Thank you, it needs to be 12k. Last question is where to locate it. A few pictures below of the layout.

Issue is there is only 10" above the window (prob. not enough for a wall unit). You'll see from the pics

https://ibb.co/pJqTvr0

https://ibb.co/n0nqPbJ

 

[EnergyProfessional]

Consider you need to run refrigerant lines. This may be harder to do in a perimeter wall with insulation and other structure in.

 

[CodyK]

It seems like you are locked in with your placement options (if there isn't space beside or above the window, then you don't really have a choice). I would think AC blowing on the bed while trying to sleep would be a nuisance, but several google searches showed examples where people used this setup and said it was fine. Pick a specific brand/size first and check the instructions, most have minimum clearances and maximum refrigerant line lengths that you'll have to abide by. Also, what is in the ceiling? If you didn't like the wall placement, you could put in ceiling cassettes.

 

[MintJulep]

There are options available where the indoor unit can be hidden with conditioned air ducted to above-ceiling diffuser units.

Might be a good option for you. For example you could hide the indoor unit in the closet.

 

[LittleInch]

Or fit sliding doors to the bedroom cupboard instead of hinged doors

Ditto the door into the bathroom.

I wouldn't want to lie on the bed looking straight at the toilet...., but if you made the cupboard doors sliding you can rotate the bed 90 degrees

Yes you can run lines inside the walls, but it isn't easy to fix them if they go wrong.

And someone must make a thin vertical evaporator unit surely?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MintJulep]

https://lghvac.com/residential-ligh...ductTypeId=a2x44000003XQyh&iscommercial=false

 

[nuuvox000]

How do you do two zones with a mini-split? Anyway, Mitsubishi is always my first choice; seem to work well. If it needs to run during winter, make sure you specify front/rear/side wind baffles and hyperheat.

 

[Designer_82]

LittleInch, that's very smart on the sliding doors.

So I like the wall unit for the bedroom (with the room created from the sliding doors)and the surface mounted cassette for the living room seems best, hung from the wood joists. Would this require a build in condensate pump?

Another thought, if you cut 1/2" holes through the existing wood studs to run line set, (assuming standard 3.5" studs) would there be any structural integrity concerns doing this?

Appreciate the help