Air Conditioning / BTU question

[AStar617]

The third floor of my home is a finished attic. There are three rooms in a row with no hallways (stairs come up to the middle room, and the other two rooms are off the left and right walls). The ceilings are also rather low and vaulted so that decreases the "cubic footage".

My question is, if the rooms are somewhere in the 12x15 range each, and there are open doorways between the 3 rooms, would a single 8000BTU air conditioner in the middle room be sufficient to cool the entire floor?

My calculations say it might be just enough (especially given the vaulted ceilings) but I would like to put it to the group for review.

Thx

 

[meltdown75]

Yes

 

[jtvang125]

If you're thinking about using a portable AC unit very likely it will not be enough. I have a 12,000 BTU PAC and it can barely cool my bedroom.

 

[AStar617]

Originally posted by: jtvang125
If you're thinking about using a portable AC unit very likely it will not be enough. I have a 12,000 BTU PAC and it can barely cool my bedroom.

I'm talking about a window unit. Even though it's not an in-wall unit, I wouldn't consider it "portable" per se (needs the external exhaust).

 

[Wheezer]

is this a window unit or a portable?

in either case, I would suggest stepping up to a 10,000+ BTU unit just to be safe.

You can get a Samsung 10,000 btu unit for $208 or a 12,500 btu for $249 at Lowes.

chances are you will need at least one fan or ceiling fans to circulate the cold air from room to room.

 

[SlowSpyder]

We use an 8,000 (maybe 10,000? I think it's 8,000, I'll have to check) window AC unit for the upstairs of our capecod home. The upstairs is about 300 sq. ft. with a vaulted ceiling also. It cools it ok if we give it time. But, if we leave it off while at work then come home, when the upstairs is really hot it takes a long time (couple hours) for the room to cool enough that you can sit comfortably in it. So yea, it'll probably cool it, but you'd probably be better off with something bigger if you're not going to leave it on all the time.

 

[meltdown75]

Originally posted by: jtvang125
If you're thinking about using a portable AC unit very likely it will not be enough. I have a 12,000 BTU PAC and it can barely cool my bedroom.

Do you live on the sun?

 

[AStar617]

Originally posted by: SlowSpyder
We use an 8,000 (maybe 10,000? I think it's 8,000, I'll have to check) window AC unit for the upstairs of our capecod home. The upstairs is about 300 sq. ft. with a vaulted ceiling also. It cools it ok if we give it time. But, if we leave it off while at work then come home, when the upstairs is really hot it takes a long time (couple hours) for the room to cool enough that you can sit comfortably in it. So yea, it'll probably cool it, but you'd probably be better off with something bigger if you're not going to leave it on all the time.

The model I'm looking at has digital controls w/thermostat, so hopefully I can just set it and forget it.

BTW, The reason I'm stuck on 8000BTU is because of a current Craigslist deal 😛

 

[SarcasticDwarf]

Originally posted by: AStar617

Originally posted by: SlowSpyder
We use an 8,000 (maybe 10,000? I think it's 8,000, I'll have to check) window AC unit for the upstairs of our capecod home. The upstairs is about 300 sq. ft. with a vaulted ceiling also. It cools it ok if we give it time. But, if we leave it off while at work then come home, when the upstairs is really hot it takes a long time (couple hours) for the room to cool enough that you can sit comfortably in it. So yea, it'll probably cool it, but you'd probably be better off with something bigger if you're not going to leave it on all the time.

The model I'm looking at has digital controls w/thermostat, so hopefully I can just set it and forget it.

BTW, The reason I'm stuck on 8000BTU is because of a current Craigslist deal 😛

Keep in mind that while it will cool the room it is in fairly well, the other rooms will be very hot. There is nothing you can do about that unless you get central air or put one in each room.

 

[AStar617]

Originally posted by: SarcasticDwarf

Originally posted by: AStar617

Originally posted by: SlowSpyder
We use an 8,000 (maybe 10,000? I think it's 8,000, I'll have to check) window AC unit for the upstairs of our capecod home. The upstairs is about 300 sq. ft. with a vaulted ceiling also. It cools it ok if we give it time. But, if we leave it off while at work then come home, when the upstairs is really hot it takes a long time (couple hours) for the room to cool enough that you can sit comfortably in it. So yea, it'll probably cool it, but you'd probably be better off with something bigger if you're not going to leave it on all the time.

The model I'm looking at has digital controls w/thermostat, so hopefully I can just set it and forget it.

BTW, The reason I'm stuck on 8000BTU is because of a current Craigslist deal 😛

Keep in mind that while it will cool the room it is in fairly well, the other rooms will be very hot. There is nothing you can do about that unless you get central air or put one in each room.

Even with open doorways between the center room and the end rooms?

 

[SarcasticDwarf]

Originally posted by: AStar617

Originally posted by: SarcasticDwarf

Originally posted by: AStar617

Originally posted by: SlowSpyder
We use an 8,000 (maybe 10,000? I think it's 8,000, I'll have to check) window AC unit for the upstairs of our capecod home. The upstairs is about 300 sq. ft. with a vaulted ceiling also. It cools it ok if we give it time. But, if we leave it off while at work then come home, when the upstairs is really hot it takes a long time (couple hours) for the room to cool enough that you can sit comfortably in it. So yea, it'll probably cool it, but you'd probably be better off with something bigger if you're not going to leave it on all the time.

The model I'm looking at has digital controls w/thermostat, so hopefully I can just set it and forget it.

BTW, The reason I'm stuck on 8000BTU is because of a current Craigslist deal 😛

Keep in mind that while it will cool the room it is in fairly well, the other rooms will be very hot. There is nothing you can do about that unless you get central air or put one in each room.

Even with open doorways between the center room and the end rooms?

The temperature, insulation, cubic feet, and layout will all have a major effect, but yes. There will be a noticeable temperature difference between the rooms. It won't be as bad if you let it run all day.

 

[Wapp]

Originally posted by: SarcasticDwarf

Originally posted by: AStar617

Originally posted by: SarcasticDwarf

Originally posted by: AStar617

Originally posted by: SlowSpyder
We use an 8,000 (maybe 10,000? I think it's 8,000, I'll have to check) window AC unit for the upstairs of our capecod home. The upstairs is about 300 sq. ft. with a vaulted ceiling also. It cools it ok if we give it time. But, if we leave it off while at work then come home, when the upstairs is really hot it takes a long time (couple hours) for the room to cool enough that you can sit comfortably in it. So yea, it'll probably cool it, but you'd probably be better off with something bigger if you're not going to leave it on all the time.

The model I'm looking at has digital controls w/thermostat, so hopefully I can just set it and forget it.

BTW, The reason I'm stuck on 8000BTU is because of a current Craigslist deal 😛

Keep in mind that while it will cool the room it is in fairly well, the other rooms will be very hot. There is nothing you can do about that unless you get central air or put one in each room.

Even with open doorways between the center room and the end rooms?

The temperature, insulation, cubic feet, and layout will all have a major effect, but yes. There will be a noticeable temperature difference between the rooms. It won't be as bad if you let it run all day.

You could also get a door frame fan that can pull the cool air out of the middle room. ``

 

[alkemyst]

My a/c (8000 btu was 11000 btu but very old) is wall mounted. My apartment is small but it cools into the bedroom, kitchen and bathroom very well. It's freezing in the mornings in S. Florida, comfortable on the hottest summer days. My square footage is almost 500 total.

 

[kalrith]

I use an 18,000 BTU (I think) AC unit to cool my 900 sq. ft. home. It does a good job even when it's 100 degrees outside.

 

[idiotekniQues]

id kick it up a bit over 8000

 

[doze]

I don't think 8000 BTU will do the job, but something like this should do the job nicely

I just got the 6300 BTU model for my bedroom and love it

 

[LennyZ]

A 5-6k a/c unit at each end may work alot better.

 

[GTaudiophile]

I got a 6250 BTU window A/C unit for the 200 sq-ft main part of my studio apartment here in Washington, DC. It seems to cool things down nicely. Then again, the really hot weather has yet to arrive.