Results 1 to 6 of 6

Thread: Cooling A Garage Shop

  1. #1
    Join Date
    Apr 2004
    Location
    Tampa, FL
    Posts
    937

    Cooling A Garage Shop

    A SMC-er who saw my post on how much fun I had insulating my shop http://www.sawmillcreek.org/showthre...7747#post87747 -- which is in my attached garage -- asked about cooling the space once it was insulated. I thought I'd repost my answer just in case it would benefit anybody else.

    As for your question on cooling my shop/garage, at first I tried installing a small -- much too small at about 5500 BTUs -- AC unit in a box in the ceiling. I rigged it so that the hot air would be able to float up into the attic. This really didn't work well, which I later found out was because the attic air is so hot to start with that there is not enough temperature differential for the condensor/compressor-thingie in the AC unit to go its job correctly. So the AC unit would blow cool air for a while, but it would gradually get warmer and warmer, until I could hardly tell the difference.

    I improved on this a bit by installing a large, cheap fan on top of the box in which the AC unit fits -- rigged so that it goes on when the AC unit is on, and blows air straight up. Thus, it pulls air from the garage to cool the freon-stuff in the AC unit. This worked better so far as cooling goes, but the AC unit itself is still annoyingly loud.

    The big breakthrough came when our house's main AC unit sprang a leak and the old repair guy who came out to fix it told me how to do it the right way. It's so simple it's almost stupid. Just cut a hole in the main outfeed leading away from the AC coil so that cold air spills from the house's AC unit into the garage. Either install a closeable vent in that hole or rig up something like a DC blast gate, so you don't air condition the garage all the time.

    Remember though, that before I did this, I insulated the garage door with about 3" of rigid foam and the garage attic with at least 8" of blown insulation. Thus I'm hopeful -- perhaps naively so -- that it will not make too huge a difference in our overall power bill. (We have not yet received one since I made the change.) If you were to try this without first installing heavy insulation, I think you could bankrupt yourself paying for the electric.
    HTH,

    Augie

  2. #2
    Join Date
    Dec 2003
    Location
    SF Bay Area, CA
    Posts
    15,331
    Augie,

    Dunno if you caught my post "Padilla's Garage Gut/Remodel" but I am going to give up some of my precious real estate in the garage and partition off the laundry area for the LOML. Contained within the laundry area are, duh, the washer and dryer but also contained are the water softener, the water heater, and finally, the furnace/blower! I am getting a new HVAC system put in and I am going to ask the guy to include a duct for the garage so I can heat or cool the garage!

    Thanks so much for the post...glad I saw this before he comes to install it! You da man!
    Wood: a fickle medium....

    Did you know SMC is user supported? Please help.

  3. #3
    Join Date
    Feb 2003
    Location
    Chappell Hill, Texas
    Posts
    4,741
    Augustus, I looked into adding a duct off my house into the attached garage at my last house. It's my understanding that this is not up to code. Car exhaust could travel through the vent into your house.

    Since your "garage" is defined as a "garage", that means you park cars in it, whether you do or not. (I didn't).

    Just a thought for you to consider. Todd

  4. #4
    Join Date
    Apr 2004
    Location
    Tampa, FL
    Posts
    937
    Quote Originally Posted by Todd Burch
    Augustus, I looked into adding a duct off my house into the attached garage at my last house. It's my understanding that this is not up to code. Car exhaust could travel through the vent into your house.

    Since your "garage" is defined as a "garage", that means you park cars in it, whether you do or not. (I didn't).

    Just a thought for you to consider. Todd
    RATS!

    I don't park cars in there now, but eventually I will have to park one in there. It's a three car garage, and I only have two stalls for use as my shop.

    UGH...

  5. #5
    Augustus,
    I thought about running a duct from my home a/c unit to the garage but was told that it would not help since the thermostat was in the house. Once the house was cooled down doesn’t mean the garage is. I went ahead and installed a 1 ˝ ton unit for the garage. I did the same as you, installed insulation on the garage door, ceiling and blown insulation into the walls (that made the most difference). I got lucky because my neighbor worked for an a/c wholesaler and got me a good deal (total cost $600.00, condencer, air handler, ducts, piping, insulation and accessories) but I have seen complete systems in the paper that are comparable to what I spent.
    Steve
    Garage A/C

  6. #6
    Join Date
    Apr 2004
    Location
    Tampa, FL
    Posts
    937
    Quote Originally Posted by Steve King
    I thought about running a duct from my home a/c unit to the garage but was told that it would not help since the thermostat was in the house. Once the house was cooled down doesn’t mean the garage is.
    Actually, I've found that it works quite well. I've got the garage nearly as well insulated as the house, which is one factor I'm sure. The other is that I open the door between the kitchen and the shop ... er ... garage at least an hour before I will be working out there. An additional factor, I think, is that the air for the shop comes out of the ducting before it hits the rest of the house, thus lowering the volume of air circulating in the rest of the house, and therefore causing the house to take longer to cool down to a given temperature.




    I went ahead and installed a 1 ˝ ton unit for the garage. I did the same as you, installed insulation on the garage door, ceiling and blown insulation into the walls (that made the most difference). I got lucky because my neighbor worked for an a/c wholesaler and got me a good deal (total cost $600.00, condencer, air handler, ducts, piping, insulation and accessories) but I have seen complete systems in the paper that are comparable to what I spent.
    Steve
    That's definitely the best way to go. Unfortunately, $600 is about $600 more than my budget will allow at the moment.

Similar Threads

  1. Shop Location - What Would You Do?
    By Douglas Robinson in forum General Woodworking and Power Tools
    Replies: 35
    Last Post: 08-20-2007, 3:49 PM
  2. Building My Basement Shop
    By JayStPeter in forum General Woodworking and Power Tools
    Replies: 31
    Last Post: 08-19-2007, 9:40 PM
  3. Shop Tour (pics)
    By Fred Voorhees in forum General Woodworking and Power Tools
    Replies: 17
    Last Post: 03-14-2004, 11:33 AM
  4. Need advice - I might get to build a new shop!
    By Matt Meiser in forum General Woodworking and Power Tools
    Replies: 24
    Last Post: 08-13-2003, 10:08 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •