Heating and cooling a garage workshop. For David Nelson1

[David Hostetler]

Since I was asked about it, I figured I would start a new thread on the subject...

No doubt I am not unique here, but in my climate, if I were to have my workshop uninsulated, without air conditioning at the least, I wouldn't be able to work in my shop at all for at least 4 months out of the year.

Insulation, and of course sealing out air penetration from the shop goes an awful long way to making things more comfortable, but due to the lack of simple things like windows, and man doors set up to allow cross flow ventilation in my garage / shop, I have to turn to technology to control the climate in my shop...

For the last couple of years I have been cobbling together a halfway functional solution. I have a shop built "temporary wall" that simply slides into the door opening with the overhead door rolled up, and clamps to the door tracks with turnbuckles. A window unit AC simply clamps into the hole in the wall, and gets turned on and cools me as I work. Now this is a VERY temporary solution as my HOA very much frowns on window unit air conditioners being visible from the street.

A while back, and I wish I had bookmarked it, but a member here had posted up his solution, which was to build a mounting / duct box that separated chambers for intake and exhaust air through the coils, mounted the whole thing up in the corner of the ceiling, then ducted it all through the soffit vent of the house. This is just about the most HOA friendly setup I have seen. But this handled just air conditioning.

In the time since I saw that, my Brother in law has put in his auto body shop office, where he works with customers, an LG 18K BTU Air conditioner that is sort of a heat pump gizmo that has a heat function. I have been giving one of those some serious consideration.

Now David Nelson1 had asked me about the LG units, and mentioned he has no ceiling, insulation, or soffts... While this is a tough setup, it's not as bad as it seems... At least with the right roof design...

You see soffit is only one way to port a vent. And mind you, I am porting through the ceiling because I cannot simply drop holes in my brick walls... But an option for me, and for you David is if you have a Gable roof, you can install a gable vent, and run your duct to there. Of course you REALLY need to insulate, but that is another subject all together. (Since you have no sheetrock, now would be a good time to do spray foam!) You could do something as simple as a pair of 5" HVAC ports to a portable AC unit that you can roll in and out (Sams Club sells them), and then heat with a portable propane heater like a Mr. Heater Big Buddy heater. (I have been using one, I have gone through less than 20# of propane in 2 years...)

Just a thought. What works for you guys and gals?

[Joe Bradshaw]

David, I have one of those combination AC/Heaters in my 24x36 shop. It works real well. I just built my shop last May and I had to run a dehumidifier until the slab and all the construction lumber and latex paint dried out. I am pleased with the unit. My electric bill for my shop runs about 60-70 dollars a month depending on the number of hours I spend in it. I insulated the slab and walls and ceiling. I am in N.C., so it does not get quite as hot as Texas.

[Ray Bell]

David, I have one of those combination AC/Heaters in my 24x36 shop. It works real well. I just built my shop last May and I had to run a dehumidifier until the slab and all the construction lumber and latex paint dried out. I am pleased with the unit. My electric bill for my shop runs about 60-70 dollars a month depending on the number of hours I spend in it. I insulated the slab and walls and ceiling. I am in N.C., so it does not get quite as hot as Texas.

I just recently installed one of these. I haven't had to use it for cooling yet, but it does a good job heating the place up. I usually turn it on early in the morning, and after a couple of hours it is warm enough in there to just shut it off. Unless of course my wife spends some time in there. She will turn it back on.

[Glen Butler]

I have a window unit that I simply install into the wall. I know you don't want to go throught the brick, but if it is to be a permanent solution, is it so bad?

Ideally you would do central air for your shop just as you would the house and put a compressor outside. You can easily run the duct work through your attic space, using spider ducts.

[David Hostetler]

I have a window unit that I simply install into the wall. I know you don't want to go throught the brick, but if it is to be a permanent solution, is it so bad?

Ideally you would do central air for your shop just as you would the house and put a compressor outside. You can easily run the duct work through your attic space, using spider ducts.

Yes it is so bad. HOA rules prohibit any through wall, or window unit air conditioners being visible from the street...

Ideally, I would have more land, and a large barn to build my shop in, and tons of money to do it with... But yeah, a central unit isn't a horrible thought either...

[Alan Bienlein]

Do you have a wall thats not visible from the street? What about some wing walls to shield it from view? There is always a way. I have a 24,500 btu window unit for my 24 x 24. I used the same insulation on the walls as my rollup door. For heat I have a 30,000 btu propane heater with a thermostat. It's ventless and I have no problems with moisture or condensation.

Do you have a doorway thats recessed enough to put the window unit in one of the side walls to conceal it?

[Alan Lightstone]

I've been real happy with a split AC unit. LG also sells these. I've got an 18,000 BTU AC unit. Very quiet, and more efficient than my central AC. Smallish quiet compressor sits outside, and just the ventilation unit is attached to the wall. Only connections go through a 3" hole through the wall. Nothing more.

[Larry Feltner]

I've been thinking about a split unit myself for my metal pole barn where I have my tools. Its 30 x 34. I am in Kentucky and maybe I talked with the wrong guy, but the one HVAC person I talked to said they were not a good application for a metal pole barn. His concern was since they don't have a heating element, it would run continuously during the winter months. My guess is that it would work well in a garage, and I thought it might work well in my pole barn, but I didn't get the answer I thought I would get.

[Joe Jensen]

I put a mini split in my 3 car garage shop in the Phoenix area a couple of summers ago. I have only run the heat mode once, but it cools nicely. One thing to consider, the mini split compressors go into a low output mode when the outside temperatire is over 110 F. I found one unit that was rated for 114. I find that if I am going to work in the shop in the summer here where it's normally 110F or more, I need to start the AC in the morning before it gets really hot. Also, even if I precool the shop to say 74, once I am using the tools and dust collector, it gets up to 82 or so. I have 22000 BTU high efficiency mini split. My garage is 600 sq ft. I have a well insulated ceiling. One wall adjoins the house, the other has large garage doors with a row of windows. I insulated the solid door panels with 2" of high grade foam. The two side walls are stucco over cheap foam, and then drywall inside. I am considering having the sidewalls foamed.

[Rick Davidson]

I would go with a mini split!! They are fairly cheap and you can install yourself some even come precharged with freon. The unit that goes out side is like a normal ac unit for your house. You could even hide it some where not visible. Also the mini splits do heating and cooling.

[Alan Lightstone]

Find one made by a known manufacturer, though. My friend and I have had some issues due to the no-name brand we chose. I believe LG and Samsung make them, probably a few other manufacturers. Google is your friend.

And not all units have heating. Mine doesn't.

[Jim Finn]

My workshop is one stall of a three car garage. I insulated it and built an insulated wall to seperate it from the rest of the garage. I installed a regular window unit in this new wall, dumping the hot air into the garage. I leave the garage door open about a foot to let that hot air out. Works well here in this high desert in West texas.

[David Hostetler]

Okay to address the issue of the through wall mount I guess I need to describe my setup.

If you would, picture my house as a rectangle, running parallel with the street. The shop / garage is yet another rectangle spun sideways, and the right side wall is flush with the right side of the main house so that it is one wall. So basically there are 3 walls of the garage that are exterior, one of those walls has the doors on them.

The other 2 walls, east, and west are less than 25 feet from the curb. The east wall is the shared wall with the house, and is 36" from the property line. That's 36 inches, not feet. So a wing wall wouldn't work at all... And I honestly don't want to eat any space whatsoever on that side of the house. It's just too tight when I mow there already, I don't want to complicate it...

The west wall MAY be an option. I can conceal a through wall unit with the Hibiscus. However another winter like the one we just had, and I sure as all get out won't be having a hidden unit come spring... My hibiscus nearly died and is just now starting to grow back.

So I am not really eager to go with a through wall setup. Just too many HOA hassles to even give it much beyond a seconds consideration. Not to mention the house is brick, so I would have to knock brick out to make the hole for it to fit. Which would be BAD for my resale value of the house... That leaves me, inevitably with a couple of options...

#1. Window unit in a ducted box mounted fully within the interior of the garage, and ducted through the attic to the soffit. The advantage here is that it is completely hidden from the street, no HOA hassles. And it requires no more frame modifications to the house than say hanging a storage basket from the ceiling. The drawbacks are that it is a big box stuck on the ceiling, and I would have to spend quality time in my attic running duct work through to the soffit, which is tough as all get out for me to squeeze my fat backside anywhere near that... I am not saying impossible, but it IS a real pain in the butt... Honestly, If I have more room between the garage door tracks, I know the perfect place to put this, I could duct it through a gable vent and be done with it, easy as pie since the gables are VERY easy to get to...

#2. Since my HVAC is slated to be updated / replaced within the next few years, extend an HVAC circuit to the shop. Not sure how that would work. I would need to have a separate zone that I could turn off for my shop. And I am sure that this would at that point create more "living square footage" that the tax office would be more than happy to tap me on the shoulder for... Not to mention I suspect this would be hideously expensive...

#3. Portable AC unit plumbed with flex hose through ports, then up to again, a gable vent. The disadvantages I see there is that would take up floor space...

#4. And an option I am SERIOUSLY considering if I can get HOA approval. I do NOT use my garage as a garage, but rather as a shop, and I do NOT need 2 rollup doors. I am considering removing the right side door, replacing it with a wall built in place, then the AC put in a cut through fairly low-ish on the wall, and hidden with some landscaping like flower pot bushes or something of that nature. I may be able to get away with this approach as there is a house on the cul-de-sac a couple of blocks away from me with exactly the setup I am thinking...

Now the unit doesn't HAVE to provide heat for me. I live in Coastal Texas, and my Mr. Heater portable heater kicked on about 10 minutes before I start working is WAY more than enough even on the coldest days here... I already have it, and it works well... And honestly I already have a window unit AC. My main unit zapped out on my in July a couple of years ago, I tossed a window unit in the master suite and kept the door to the rest of the house closed until we got that fixed... Its a Goldstar (not exactly a great unit, but good enough) and I think it is a 12K BTU unit. More than enough to cool my garage...

[Ray Bell]

You say the right side of the garage is flush with the right side of the house, so it is essentially an attached garage? If this is the case I would think option 2 would be the best, and maybe the cheapest. It wouldn't be too expensive to run a new duct to the garage, As far as a new zone, couldn't you just add a manually operated open/close vent into the garage?

[David Hostetler]

You say the right side of the garage is flush with the right side of the house, so it is essentially an attached garage? If this is the case I would think option 2 would be the best, and maybe the cheapest. It wouldn't be too expensive to run a new duct to the garage, As far as a new zone, couldn't you just add a manually operated open/close vent into the garage?

My concern there would be return air... And yes, it is an attached garage... Not my choice, but what I am stuck with.

I always wanted a detached 3 car garage with a loft. Now I know why...

[Alan Lightstone]

http://kingersons.com/LGsplitairconditioner18kh.html

Can easily hide a split unit's compressor behind a bush.

Outside part:
http://kingersons.com/lgsplitcompressor.jpg



On wall part:
http://kingersons.com/lgsinglezone.jpg

Need a 3" hole to connect the refrigerant lines and drain between the two.

[David Hostetler]

http://kingersons.com/LGsplitairconditioner18kh.html

Can easily hide a split unit's compressor behind a bush.

Outside part:
http://kingersons.com/lgsplitcompressor.jpg

On wall part:
http://kingersons.com/lgsinglezone.jpg

Need a 3" hole to connect the refrigerant lines and drain between the two.

That's a nice looking system, but it comes at a pretty steep price tag compared to a portable unit...

[Alan Lightstone]

That's a nice looking system, but it comes at a pretty steep price tag compared to a portable unit...
No doubt. Quiet and efficient, but not cheap. On the other hand, if it was running a lot in a hot climate, the extra efficiency might pay for itself.

[Dave Beauchesne]

David:

I am an HVAC guy; if I may add the following:



Okay to address the issue of the through wall mount I guess I need to describe my setup.

If you would, picture my house as a rectangle, running parallel with the street. The shop / garage is yet another rectangle spun sideways, and the right side wall is flush with the right side of the main house so that it is one wall. So basically there are 3 walls of the garage that are exterior, one of those walls has the doors on them.

The other 2 walls, east, and west are less than 25 feet from the curb. The east wall is the shared wall with the house, and is 36" from the property line. That's 36 inches, not feet. So a wing wall wouldn't work at all... And I honestly don't want to eat any space whatsoever on that side of the house. It's just too tight when I mow there already, I don't want to complicate it...

The west wall MAY be an option. I can conceal a through wall unit with the Hibiscus. However another winter like the one we just had, and I sure as all get out won't be having a hidden unit come spring... My hibiscus nearly died and is just now starting to grow back.

So I am not really eager to go with a through wall setup. Just too many HOA hassles to even give it much beyond a seconds consideration. Not to mention the house is brick, so I would have to knock brick out to make the hole for it to fit. Which would be BAD for my resale value of the house... That leaves me, inevitably with a couple of options...

#1. Window unit in a ducted box mounted fully within the interior of the garage, and ducted through the attic to the soffit. The advantage here is that it is completely hidden from the street, no HOA hassles. And it requires no more frame modifications to the house than say hanging a storage basket from the ceiling. The drawbacks are that it is a big box stuck on the ceiling, and I would have to spend quality time in my attic running duct work through to the soffit, which is tough as all get out for me to squeeze my fat backside anywhere near that... I am not saying impossible, but it IS a real pain in the butt... Honestly, If I have more room between the garage door tracks, I know the perfect place to put this, I could duct it through a gable vent and be done with it, easy as pie since the gables are VERY easy to get to...

Window units are not meant to be ducted in any way, be it from the hot air side of the cool air side - doing so will very likely give unsatisfactory results.

#2. Since my HVAC is slated to be updated / replaced within the next few years, extend an HVAC circuit to the shop. Not sure how that would work. I would need to have a separate zone that I could turn off for my shop. And I am sure that this would at that point create more "living square footage" that the tax office would be more than happy to tap me on the shoulder for... Not to mention I suspect this would be hideously expensive...

Code here in Canada ( and it should be checked for your jurisdiction )does not allow a ' garage ' to be conditioned with the same unit as the rest of the house. If it is allowed, however, consider the fact you will be mixing house air with shop air, which, can have undesireable properties.

#3. Portable AC unit plumbed with flex hose through ports, then up to again, a gable vent. The disadvantages I see there is that would take up floor space...

Floor space aside, these units are not meant to have excessive flex duct hooked up to them to get rid of heat. Adding such, and trying to get the heat up to the attic - - - very likely trouble brewing. As well, these units ( all the ones I have seen anyway ) are on the ' cheap ' side.

#4. And an option I am SERIOUSLY considering if I can get HOA approval. I do NOT use my garage as a garage, but rather as a shop, and I do NOT need 2 rollup doors. I am considering removing the right side door, replacing it with a wall built in place, then the AC put in a cut through fairly low-ish on the wall, and hidden with some landscaping like flower pot bushes or something of that nature. I may be able to get away with this approach as there is a house on the cul-de-sac a couple of blocks away from me with exactly the setup I am thinking...

Perhaps the best alternative - - - -

Now the unit doesn't HAVE to provide heat for me. I live in Coastal Texas, and my Mr. Heater portable heater kicked on about 10 minutes before I start working is WAY more than enough even on the coldest days here... I already have it, and it works well... And honestly I already have a window unit AC. My main unit zapped out on my in July a couple of years ago, I tossed a window unit in the master suite and kept the door to the rest of the house closed until we got that fixed... Its a Goldstar (not exactly a great unit, but good enough) and I think it is a 12K BTU unit. More than enough to cool my garage...

12,000 btu to cool a 2 car garage in a hot climate ??? Sounds light to me, but I am thousands of miles away -

JMHO -

Dave Beauchesne

[David Hostetler]

12,000 btu to cool a 2 car garage in a hot climate ??? Sounds light to me, but I am thousands of miles away -


I am kind of going by MFG ratings. Mind you, my 2 car garage is on the small side of things. (18x20' with 8' 6" ceiling height.). I am kind of going with the manufacturers ratings, and then upsizing a bit. My shop is 360 square feet, a 12K BTU unit is rated according to the MFGs for 550 square feet. I figured I was safe upsizing to that point to compensate for the climate... Mind you the garage will eventually be fully insulated with R30 in the ceiling (present status), R10 with radiant barrier in the doors (Have material, project in progress) and R19 in the walls.

A HUGE part of my resistance to attaching the shop to the house main system is sharing of air between the house and the shop. That just screams bad idea to me, but there may be smarter people out there that know how to make it work well. I'm not that good...

I am honestly leaning hardest toward replacing an overhead door with a wall, plopping a window unit in it, and hiding said window unit with a flowerpot garden which my lovely bride loves to play with anyway...

[Edward Bartimmo]

Great ideas. I am also in the Houston area and it is constant issue between heat and humidity in my garage workshop along the Gulf Coast. One of the biggest improvements was to change out the standard garage door to a insulated door. This probably dropped the temperature in the garage by 5 to 10 degrees in the summer. It is starting to get hot enough that I have been seriously considering installing A/C. As mentioned in other emails my HOA are Nazis...no fly for window unit. A small exhaust duct might work if I run it out the garage attic!

[David Hostetler]

I have been thinking about this some over the weekend as I installed insulation in my doors. Okay one door, still need to do the other one, but that is beside the point... Looking at the post between the doors, I know I can run ducts at the bottom of this thing, and the Mums that my wife has planted there would more than conceal the view from the street. I need to replace some of that wood there anyway due to a slight error in judgement while backing a vehicle up (not mine, nor my current wife's but somebody else who had trouble making a car go backwards without hitting stuff). This would allow me to use one of those portable units. Still not sold on those though, they seem poorly made, and gobble up priceless floor space...