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Old 03-13-2013, 03:07 AM   #1
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Ductless Minisplit question


Would a 9,000 btu minisplit unit be enough to heat and cool a 200 sqf room easy, fast, and efficiently?

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Old 03-13-2013, 11:47 AM   #2
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I would generally say yes, if you are asking this about a typical bedroom or living space in a finished house. There could be unusual circumstances however that could make it not enough, or too much. A mini-split works great for basically picking up where a home's central HVAC system leaves off, like in a room that was added onto the home, or simply one that has a " end of the pipe" problem where too little heat or cooling gets to it. There are some circumstances to watch out for however.

Too much overall, if this is an interior space largely surrounded by other conditioned spaces, or if the space has very good insulation, the way many new homes are constructed with.

This could be too little on the cooling side, and too much on the heating side if the room experiences lots of sunlight or has a lot of heat producing devices in it, like electronics from a home entertainment system, computers, or cooking appliances (yes, even coffee makers and refrigerators). Also, if the room gets a lot of "human" load from lots of people. In this case, save some money and get a straight air conditioner.

It could be too little heating, and too much cooling if the room has large windows and doesn't get much sunlight (shade, or on north side) or has a door that's frequently opened, or the room gets a fair amount from a central AC. In this case, you may just want to get a baseboard heat strip.

also bear in mind your outdoor climate. Mini-splits are heat pumps, and most heat pumps don't heat well when the temps get below 30 F degrees or so. If you are in a humid climate too, you don't want to over-size the air conditioner side, or it won't do good with humidity.


As you can see, there's lots of variables involved here!

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Old 03-13-2013, 04:17 PM   #3
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Sorry I should've explained my room better. It's an air sealed theater room. No windows. Well insulated.
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Old 03-13-2013, 04:55 PM   #4
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Ductless Minisplit question


Never seen a mini split rated in BTU's before. But then again I'm not in the HVAC business.
A one ton unit will work fine. 9000 Btu's is .75 tons.
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Old 03-13-2013, 05:38 PM   #5
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Originally Posted by joecaption View Post
Never seen a mini split rated in BTU's before. But then again I'm not in the HVAC business.
A one ton unit will work fine. 9000 Btu's is .75 tons.
They come rated in BTU also.
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Old 03-13-2013, 05:39 PM   #6
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How many people are going to be in the theater room. What equipment will be in it.
These things will also determine what size you need.
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Old 03-13-2013, 05:43 PM   #7
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For the most part just my wife and I. But it will seat 6 so here and there 6 at most. Getting a Panasonic projector, receiver, bluray player, 7.1 surround.
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Old 03-13-2013, 05:53 PM   #8
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Find out either the KW rating the equipment in the room will have, or its VA rating(volts times amps equals watts). Convert that to BTUs(watts times 3.413 equals BTUs). 6 people will be 2,700 BTUs. So add that to your equipment's heat.
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Old 03-13-2013, 06:34 PM   #9
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Wow very helpful thank you. Do speakers give off anything that would affect the total btu's? Also I should include the lights correct?
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Old 03-13-2013, 08:42 PM   #10
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Speakers are added only if the amp/source of power is in another room.

Yes, add the lights.
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Old 03-13-2013, 08:46 PM   #11
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With everything including people i'm looking at around 8400 btu's. Should the 9000 btu unit be fine? Also, do you know anything about how these things are installed?
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Old 03-13-2013, 08:52 PM   #12
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That puts your sensible load at about 6,900. A 9000 BTU will barely do that. Might want to consider a 12,000.

They are easy to install. You do have to think of whee the condensate is going to drain to before you install it.
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Old 03-13-2013, 09:09 PM   #13
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ok 12,000 I can do. Does the condensate line run from the unit that's in the room?
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Old 03-13-2013, 09:13 PM   #14
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Also are these things pretty dependable? This is going in my finished theater room and would rather not have to rip open drywall that I have soundproofed to the unit.
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Old 03-15-2013, 07:34 AM   #15
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Modern audio amplifiers are pretty efficient and don't really give of a lot of heat. If you are using professional amplifiers like QSC's, Crown, or other pro audio amplifiers, most of these are "Class D" amplifiers, which can be as high as 75 percent efficient at converting power in to power out at the speakers. This means that they run rather cool. Also bear in mind that you will probably rarely ever be running the amplifiers continuously at full volume. Even with loud parts of the movies, they may only hit maximum power output about 50% of the time if you got the system fully cranked, just because of the dynamics in recorded sound, so for the audio amplifiers, only factor 1/3 to 1/2 of the rated wattage as the heat load. These amplifiers too run perfectly cool at low volumes and at idle.

Now, if you are running old-school amplifiers, like older home audio gear, audiophile gear, or older professional gear (Like Crown D300's or someting) These amplifiers are usually class AB, and are only about 50% efficient. Many audiophile amplifiers are even less than that on efficiency. They sacrifice efficiency for low distortion numbers (Although I can't tell much diff between them!) These amplifiers also generate heat when they are at idle! If you are using these type amplifiers you may want to factor every watt of output power as heat energy added to the room.


I point this out because I have seen professional AV equipment rooms over-cooled in my trade because the amps are only being used at low volumes for background music, and the HVAC tech factored every watt the amps are capable of producing for their load calculation.

As far as the projector goes though, count on it's full wattage being generated as heat!

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