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imported_John D 09-08-2004 12:50 AM

Too hot in an attic room
Attic to hot

I made a small room above my garage. Kinda a office of sort. There are no windows to install a A/C unit and it gets way too hot. A friend told me to put central A/C in. This seem a bit overkill to me and I am afraid what it would do to my electric bill! I have no ceiling height for a ceiling fan either. I get way hot during the day even with two stand up fans running full out. Anybody know what to do? --besides wait for winter--

John D.:eek:

MgMopar 09-08-2004 07:31 AM

Hi, John D
Ok, I know of two different solutions. If it is a small room either one help a lot. If you have a dark colored roof that makes it harder to cool attic type spaces, so keep that in mine wile making the selection.

The preferable solution energy wise is a split A/C system. This is similar to a central air but avail much smaller and most don't provide heat. This choose will be much more energy efficient then the second but is also harder to install. A line set has to be ran to an outside condensing unit. If you own and use this space a lot, I would go this route. (most cases would be not DIY)

The second is a spot cooler. These units generally use allot more energy. They require about a 4" duct hole to the outside (same as a dryer vent) this passes the hot air out. It is a self contained unit no line sets to run. (this is DIY)

I found some links for examples so you can get a better idea of the differences to make you choice. I found these on a web search, so I would not be able to give any recommendation were to purchase.
Split A/C systems

Spot coolers

Suppliers should be able to help you with sizing the following information may be important to tell them.
The size of the room.
That it is attic space!
Type of roofing and insulation/is their ventilation above the insulation
Heat sources in the room or area i.e. computers, televisions, copiers (this stuff can add up)
They may ask more but that is about what I would need to know to get you in the ball park.
Don't forget the color light or dark of your roof also makes a difference.

imported_Alan 09-09-2004 04:15 PM

Hey John,
If you want an easy fix put in a attic fan to draw the hot air out. There are a heap available at local hardware stores, I just put a whirly bird in the roof of my 2 door garage and it made a heap of difference. If I had to do it again I would use an electric thermo fan like the one I put in my house, as on still days she still heats up. The electric units range anywhere from $40-$120 and are pretty easy to install.

If your shed is pretty cool downstairs like mine is when you first walk in you'll find this will make a big difference.

imported_John D 09-09-2004 07:47 PM

Thanks alan and mgmopar for the replies,

I don't know if Alan's idea would work this room? It's closed off from the lower part so it can't get the cooler air. I am basically up their in a closet! A lot of dust down in the lower part. Wife sands on ceramics figures and stuff. She has a window A/C unit in their but her filter keeps clogging up. I don't think anything can help that! I am looking at maybe having a remote type unit installed. When I talked to a A/C guy down the street he said it is not too big of a project to install. By the way I do have Black shingle roof and the insulation is between the rails or beam things going to the peak and I drywall over that. The drywall is warm to the touch in the middle of a sunny day! I would like it to be nice even on warmer days. I do my ebay sales and video games from up their. I do have a small fridge and a fax as well as a 27" color and a playstaion and xbox with 100watt per channel DVD surround sound unit. I understand this stuff does put of heat. I would be interested about how big of a unit I should get. I would like to compare opinions before commiting. Oh the room is about 7 by 12 with a varying ceiling height of 5 to 7 1/2 feet.

MgMopar 09-09-2004 08:26 PM


So I see you are putting some heat in the room too. You say the drywall gets warm to the touch? Do you recall what insulation value you have? How is that roof! time to do soon? If you go with a light gray or something it helps quite a bit. Well, I probably can work up a suggested size for a unit. What area do you live in? Have you taken any temp readings on a hot day? Are you near a straight out side wall? if so still maybe able to go with a window unit just by framing an opening for it. Alan's way is a lot more cost effective, I didn't really think of it, should work great in many situations. But thinking of venting this might help the wife's area. If you could put an exhaust hood near wear she sands this might exhaust some dust before it reaches the A/C filter. Or maybe you could make a sorta prefilter out of some bulk filter material? (shouldn't restrict it any more then the clogged filter would). If it wasn't for the dust I would recommend using a central unit to cool off both spaces. It would be possible with two evaporators but this would make for a more complex system and a lot more installation expenses.

imported_John D 09-10-2004 10:05 PM

Hi MgMopar

My roof joists were only 2x4 so I used R11, I knew this wasn't as good as it should be I didn't want to lower the ceiling any though.
My roof is in pretty good shape I would like to leaving for a few years, The house is medium gray so when I do it will be lighter.
I live in Indiana hot summer cold winter although seems to heat ok.
I Don't have any outside walls that are straight the sides are both angled to the top and in front there was the garage door track I stayed away from and I put stairs at the back.
Thanks about the advice on the wife's A/C I am first going to try and add a filter, hopefully make easy enough she can change it! Hopefully I a wash them off and always have a spare for her.
Buy the way the A/C guy down the street asked If I had 220 out to the garage. I don't but is a 40 amp breaker for the line to it and the wires look thick. He said he can install but not sure on selection. I guess he is just repair/install said it would be a hassel to get his boss involved.
If more power is needed the house is only like 10 feet away and their is a deck that we can run a conduit under easily.
oh for about how hot it gets. I made the mistake of having a candle up their, then had a wax covered table and carpet instead. I have been up their for a short time when it read 110 F that is high as that thermometer reads! I don't know how much hotter it gets.

MgMopar 09-12-2004 07:52 AM

Hey John

I didn't forget about you! I am just trying to come up with a btu input for that roof of yours. I am planning to run your room threw a (manual J model) to come up with a unit size. This will take in the heat input to the room for sizing. The sizing is important. Too small and everyone realizes it won't work good. I we goto large and the problem's can be just as bad. The unit won't remove the humidity and the room will be mildewy, The unit will draw more electricity then necessary, The most important problem to watch out for is the unit would probably "short cycle" and have a short life. I don't no what your electrical codes are and if you can run the conduit under the deck? But not with a split system you could run you condensing unit closer to the house. Most areas do not limit your run for AC lines. You would want to make sure they are run so no damage would occur to them. Even if you get the unit installed some contractor my let you use coiled copper for the run your self. My save some $

MgMopar 09-16-2004 12:37 PM


All it would seem you will need is about 6000 Btu of cooling. I am myself somewhat hesitant on this because of the hot drywall surface you spoke of I would most likely go bigger anyway. The smallest units I am finding for the split system are about 8000 Btu. Good news is the has a seer rating anywhere from 11 to 13 seer. This is better the most equivalent window units. I would recommend going with one of the smaller split units with a hard start cap installed on the compressor and a digital thermostat with a delay turn on built in. Mount the thermostat out of the air stream of the unit! This should help prevent any damage that would be caused by the larger unit trying to short cycle. I really don't think you will end up with the humidity problems when over sized due to you location not having added humidity sources such as cooking or bathing. I hope I helped and feel free to get a second opinion if it differs post the other recommendations.

Good Luck,

imported_John D 09-17-2004 12:40 PM

Thanks For all the input

The guy down the street talked to his boss about what are plan was. I guess his boss has a new - old stock split system he had ordered for a kitchen or somthing. he said it should work good in my application. He thinks it was 9000 btu and he liked your recommendation of the hard start cap said he had a universal one? I asked about the delay on the termostat, he said I could allways add it later if I run into probblems. Anyway this is the weekend they are BOTH installing it. Hopfully we still have a couple hot days this year so I can really test it out!:cool:

imported_John D 09-23-2004 12:23 PM

Just to let you all know I have my space! It is nice up there now. It seems to be all good a bit more $ then I would liked to spend. But it is neat equipment. Remote A/C without central - Who knew? Thanks mgmopar for your ideas and advice. Also thanks Alan for your economical proposal. :D :cool: :D

Chantel 07-27-2005 07:07 AM

Hi John,

What kind of insulation do you have in the attic? People tend to forget that insulation is a summer as well as a winter product. In the summer insulation keeps a room cool and in the winter it keeps a room warm. Try visiting

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