cooling a garage discretely/cheaply

[nexusroot]

Hey guys!

I have a 20x22x10 garage up in Ohio. I estimate I'll need at least a 15,000 BTU unit to cool it down to 80, make it comfortable to work in w/ a good fan pointed on me. Most of the work I will do in there is auto/mechanic type stuff. I don't need it cooled/controlled 24/7 (although it would be nice).

Problem is A, garage doesn't have windows, nor would HOA allow windows put in. Therefor i cannot use a Window unit traditionally.. B, I'm trying to go cheap on this one or I'd probably just drop a grand on a decent split/ductless AC unit and discretely run some refrigerant lines in.

So I see a few choices I'm having a hard time shuffling out:

1. Insulate the other 3 walls and ceiling - no problem. Will have that done this week.
   
2. Portable AC Unit - for a new one @ that BTU price will be around 500$ and from all I can tell they do not cool nearly as well as an equally rated window unit. For exhaust purposes I'm thinking about running the 4" exhaust pipe in a vertical insulated duct to the attic of the garage. The attic is uninsulated minus the bottom/ceiling side I'm going to do. The attic has soffits and roof vents in it for natural ventilation, so dumping my exhaust in there should just push it out of those vents no problem. I don't know what other effects if any this will have.
   
3. Split/Ductless AC Unit - I like this probably the best, if it wasn't for the price. I'm too darn cheap right now to drop 1k on this project.
   
4. Hooking it up to house AC or open vents to adjoining rooms - i don't know if this is wise just because of chemicals/fumes/noises in garage, that even if vents were shut, would bypass some and leak into house inadvertently.
   
5. Window AC Unit - I cant stick it in the wall sticking out the side of the garage, and I cant put in a window to put it in. The only option I see here is building some box, or by some means capturing all exhaust from the window unit in a sealed fashion and venting it up into the attic (much like the portable unit design). I'm not sure yet how to achieve this but this could be the most promising. You can pickup used window units for 50$ on craigslist, new you can find a good deal for 250 tops. it'll be much more powerful then the portable unit. Only drawbacks i see is a possible condensation problem (probably easily captured/dealt with), weird configuration with venting.

If anyone has any input on the above ideas (especially the last one), or one of their own that would be great. If you want anymore information let me know! My budget is roughly 500$ (200 of which will be spent in r13insulation). I'm not looking for a necessarily permanent solution, i don't intend to be living here forever, lol. I would like to cool the garage to about 80* minimum (planning for an outside temp max of 95*). Humidity is ~ 60%, so evaporative coolers and heat pumps on scale/price range would not suffice. I'm not big into aesthetics inside the garage, if function trumps it. So some sort of ugly box/capturing device for the window AC unit exhaust and vertical vents for it, do not bother me. What happens in the garage, stays in the garage

Yep thats all i can think to include. Let me know thoughts!

Thanks!

 

[930dreamer]

This is a long shot, but can you tap into the house system? Maybe a portable unit on a stand?

 

[Alchymist]

[*]Hooking it up to house AC or open vents to adjoining rooms - i don't know if this is wise just because of chemicals/fumes/noises in garage, that even if vents were shut, would bypass some and leak into house inadvertently.

!

If you think the HOA is gonna give you grief, it's nothing compared to what code enforcement will do if you do this!

 

[nexusroot]

If you think the HOA is gonna give you grief, it's nothing compared to what code enforcement will do if you do this!

lol yes good point. although, I don't plan on having any inspectors out anytime soon . That is the option I'd do the least, obviously because of the fumes/chemical concern more then anything. But i just listed all possible options i could think of previously, regardless of practicality.

same to 930dreamer post ^^

thanks guys! any ideas on what i can do or suggestions on my other options?

 

[welder4956]

Use a window mount AC, but mount it completely inside the garage. You would need to cut a hole in the wall big enough for the back of the unit to vent, then build an enclosed box inside the garage for the part that normally be outside. Put a metal louvered vent on the outside wall so the back of the AC can't be seen. Make sure you have a drip pan or drain for the condensate to drain to the outside.

 

[kywildcat]

How about making the exterior of the AC to look like a flower box and maybe even put a couple extra boxes on there, to make it look consistant!

 

[Wanna Ride]

Don't install a window. Just an opening big enough for a "window-style" unit.

 

[nexusroot]

Don't install a window. Just an opening big enough for a "window-style" unit.

Thanks, I cant have one actually sticking out of my house supposedly.

The other idea of hiding it kind of on the outside sounds alright, i wonder about sound/if it'd be obvious there is one though?

Can I just build a sheet metal box around the AC unit and funnel it down to a 4" vent on the back, like a dryer vent? Not sure how easy that would be though.

 

[jimp]

I use one of these to spot cool my shop before I turn on the main AC. It works pretty good. I just place a spacer under the garage door and stick the 6" hose through it. Or you could just use a oversize vent in your wall in a out of the way location, 6" round hole is a lot smaller that a window.

http://www.homedepot.com/Building-M...splay?langId=-1&storeId=10051&catalogId=10053

 

[Joe92GT]

Thanks, I cant have one actually sticking out of my house supposedly.

The other idea of hiding it kind of on the outside sounds alright, i wonder about sound/if it'd be obvious there is one though?

Can I just build a sheet metal box around the AC unit and funnel it down to a 4" vent on the back, like a dryer vent? Not sure how easy that would be though.

Is it that you can't have one sticking outside the house/garage, or you can't have one at all?

I can see why (thought i don't agree) that the HOA doesn't want window mount units, they can get ugly.

But what I can't see is why they would care one bit if there is nothing on the wall but 24x12 or so vent as mentioned above. This gets you a cheap unit, vented easily outside, with no bad looks.

 

[nexusroot]

Is it that you can't have one sticking outside the house/garage, or you can't have one at all?

I can see why (thought i don't agree) that the HOA doesn't want window mount units, they can get ugly.

But what I can't see is why they would care one bit if there is nothing on the wall but 24x12 or so vent as mentioned above. This gets you a cheap unit, vented easily outside, with no bad looks.

To be honest - i'm not sure about the full size vent. i know I cant have one sticking out but i suppose the theory of just butting one up to the wall w/ a full size vent would circumvent that. I will have to inquire, but being as ridiculously strict as they are I wouldn't be surprised if they don't want it.

I use one of these to spot cool my shop before I turn on the main AC. It works pretty good. I just place a spacer under the garage door and stick the 6" hose through it. Or you could just use a oversize vent in your wall in a out of the way location, 6" round hole is a lot smaller that a window.

http://www.homedepot.com/Building-M...splay?langId=-1&storeId=10051&catalogId=10053

Curious what size shop do you have, how quickly does it cool it down (numbers of temperature differences?). I had looked at that one a long with several others. It just seemed most of the reviews I came across for portable standalone units like that were they worked nowhere near as good as a Windows unit of equal BTU's (doesn't make much sense unless someone's fudging some numbers there). But from what I've read 50% of people are utterly disappointed in portable units. This specific one and its 12k/10k brothers in model, got bad reviews about performance, and window mount (except @ HD).

That doesn't necessarily mean they're bad, maybe people are just expecting too much, or maybe they have 12' ceilings, or its 105* outside, or no insulation. They hardly include all the variables needed to accurately judge something like these. I just hate to blow money (that specific one) on shipping it to me and then back if I have to return it (i'd loose 70$ in shipping if i wanted to return that, assuming there's not a restocking fee which there probably is). So if you have a good detailed review, please let me know!

Thanks everyone!

 

[Cougar67]

What is your HOA's position on mini-splits? My HOA is against window A/C's but there are many mini-splits supporting third floor conversions here. If they allow them I would guess they really won't notice a window unit installed through the wall of your garage. Just put it on a side of your garage that doesn't face the street and paint the surround to match your house. If it's installed through the wall it's not a window unit any more!

 

[jimp]

Curious what size shop do you have, how quickly does it cool it down (numbers of temperature differences?). I had looked at that one a long with several others. It just seemed most of the reviews I came across for portable standalone units like that were they worked nowhere near as good as a Windows unit of equal BTU's (doesn't make much sense unless someone's fudging some numbers there).

Thanks everyone!

I don't use it to cool all my shop, I use it to spot cool. I move it from the garage area to shop areas as needed before it gets real hot. My wife's wood shop area is 24'X20'X9' (about the same as yours) and very well insulated. It does a good job of cooling that area but when it gets around 90, I use the main unit (4.5 tons) to keep the whole shop cooler, so I can't give you a good answer to your question.

If you really need to know how well it will cool, if it gets to 90 here in the next few days, I'll set it on max cool and see how low it gets in my wifes shop after a couple hours.

Also, I just picked that one as a quick example I could show, mine is a Sharp 15,000 BTU unit. Does it work as good as a window unit, I don't know, seems to be the same.

Just wanted to give you other ways of hiding your cooling unit.

 

[rickairmedic]

I have an LG 9,000 BTU portable I picked up at Homie Desperate . My garage is roughly the same size as yours 20' deep 24' wide and just shy of 10' high . I have an insulated 16X7 door and it is an attatched garage . The other 2 walls I assure you have no insulation in them ( yet ) . I can keep my garage between 74-80* ( as long as I keep the overhead door shut ) . I think I paid around $299.00 for it before Military 10% discount and before tax ( you can use a Lowes 10% off card at most Home Depots ) they are in the moving packets at the post office . We get over 100* here in the summer with the heat index and humidity Rivals Fla alot in the summer . I own an HVAC company by the way and will eventually do a mini split in my garage but for now the portable does the job and I have better things ( according to SWMBO ) I could spend the mini split money on right now .


Oh yeah Home Depot has a 30 day return policy if you keep the box and your receipt .


Rick

 

[nexusroot]

What is your HOA's position on mini-splits? My HOA is against window A/C's but there are many mini-splits supporting third floor conversions here. If they allow them I would guess they really won't notice a window unit installed through the wall of your garage. Just put it on a side of your garage that doesn't face the street and paint the surround to match your house. If it's installed through the wall it's not a window unit any more!

Not 100% sure. I know that the outside AC unit has to be outback and out of sight from the front, for the most part. The only thing im not sure on is if i can run the refrigerant lines along side the house or if id have to bury them/go through the house. Not sure if they have something against that. I like the split AC, and it would be my idea choice, if I could pickup a +14kbtu unit for less then 1,000$.

I don't use it to cool all my shop, I use it to spot cool. I move it from the garage area to shop areas as needed before it gets real hot. My wife's wood shop area is 24'X20'X9' (about the same as yours) and very well insulated. It does a good job of cooling that area but when it gets around 90, I use the main unit (4.5 tons) to keep the whole shop cooler, so I can't give you a good answer to your question.

If you really need to know how well it will cool, if it gets to 90 here in the next few days, I'll set it on max cool and see how low it gets in my wifes shop after a couple hours.

Also, I just picked that one as a quick example I could show, mine is a Sharp 15,000 BTU unit. Does it work as good as a window unit, I don't know, seems to be the same.

Just wanted to give you other ways of hiding your cooling unit.

Thanks Jimp! So it sounds like this unit does work out for you adequately, you just turn on the bigger unit above 90*. Do you try to maintain 70-75 in that room? Also a "wood workshop", lots of power tools generating heat?

I have an LG 9,000 BTU portable I picked up at Homie Desperate . My garage is roughly the same size as yours 20' deep 24' wide and just shy of 10' high . I have an insulated 16X7 door and it is an attatched garage . The other 2 walls I assure you have no insulation in them ( yet ) . I can keep my garage between 74-80* ( as long as I keep the overhead door shut ) . I think I paid around $299.00 for it before Military 10% discount and before tax ( you can use a Lowes 10% off card at most Home Depots ) they are in the moving packets at the post office . We get over 100* here in the summer with the heat index and humidity Rivals Fla alot in the summer . I own an HVAC company by the way and will eventually do a mini split in my garage but for now the portable does the job and I have better things ( according to SWMBO ) I could spend the mini split money on right now .


Oh yeah Home Depot has a 30 day return policy if you keep the box and your receipt .


Rick

Thanks Rick! I didn't know about the Lowe's 10% thing, I never really looked through the change of address packet you get at USPS, great tip! My local HD didnt really have anything decently priced, thats why I was resorting to online for a better deal, and afraid of shipping prices in returning. It's good to hear a 9kbtu unit cooled your uninsulated room! That's quite surprising/hopeful. The 9k units do seem to cost 200$ less then the 14k+ ones, so that would be great if it worked for me. Is this the unit you got? http://www.homedepot.com/h_d1/N-5yc1v/R-202051352/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053



I'll have to highly reconsider the portable units based on the last few responses.

Thanks!

 

[rasit]

These run off a hose and work great. Might be just what you are looking for. Not sure of the $$$.

 

[Mike007]

Can I just build a sheet metal box around the AC unit and funnel it down to a 4" vent on the back, like a dryer vent? Not sure how easy that would be though.

Ummmm.....No.

 

[nexusroot]

These run off a hose and work great. Might be just what you are looking for. Not sure of the $$$.

Is that some sort of evaporative cooler? I heard they don't really work well in high humidity environments.

Ummmm.....No.

Thanks?

 

[larry_g]

I think that one of the problems with a window unit hidden inside is that your going to need TWO air ducts. One to bring in the the cooler outside air for the air across the condenser and a duct to carry the hot air away from the condenser. If you only have one hole then the air is just going to circulate in the side and out the back only to be sucked in the side again.

lg
no neat sig line

 

[jimp]

I don't have a problem keeping the temp in the 70's. However, outside walls and ceiling are R 40 and inside walls are R19 (only 2X4 wall).

Since the unit works for me, I never gave the function much thought. This type of unit is always exhausting conditioned air and making up with outside unconditioned air. So you will always need a slightly bigger unit than a window unit. They are not messing with the numbers, it's just a function of the type.

 

[nexusroot]

Thanks everyone for your input. I got a bunch of free blow-in insulation today which will cover my attic w/ a good +8". I spent 60$ on r13 insulation for my two walls that needed covered. And I bought that 1400btu haier unit linked above from home depot for about 450$. I also got a 20" floor fan that can be wall mounted for 30$ - which should help make a big difference in perceived cooling.

So that put me in my price range (540$).

I'm hoping the 1400btu will be overkill for my sized garage, and can cool it down rather rapidly (only need it cooled when I plan on being out there, don't want to have to wait a few hours first though). I suspect the 1400btu will cool it down from about 90-80*F within 60 minutes. If I didn't want rapid cool down the smaller same model (1200btu) was about 80$ cheaper, but take 15-30min longer for the initial cool down (assuming its non-linear). Also the 1400 unit will work better on my main floor which is fairly open and almost 1k sqft.

I have flexible duct, I'm going to take it and wrap it with r13 insulation to use as the exhaust pathway for the AC motor's heated output, and vent it to an exterior wall w/ dryer vent/dampener.

For air intake maybe ill just crack the interior house > garage door an inch when cooling it down initially. Should note this unit has an intake port that looks like you can hook a pipe up to, and in theory I could pull intake from the exterior through another pipe/duct. However pulling the cooler air from the room should cool it faster, so I'll probably stick with the door as the intake exhaust.

I think that covered about all my questions/plans, and I'll report back how well it works, in case anyone else comes upon this thread wanting to do a similar project.

Other reasons why i went with portable unit:
*I can move it inside the house when not using it in the garage (probably only need in garage on weekends, and maybe one or two random evenings a week). Considering I have a very underpowered, old, inefficient central system, using this to cool the main floor will actually save me money on my electricity bill (10-20 a month).

*it's not permanent, if i move in a few years, i don't have to disconnect the lines from a split unit and recharge it.

*Cheapest option next to the box around the window unit idea (and getting window unit used on craigslist). I chose not to go this route for how bulky and ugly it was. Also it would make it difficult for my wife to move it inside should she want to use it like we would the portable on wheels. However, I'm pretty sure I could've accomplished this idea for 100$ w/ used unit, 300$ w/ new unit (both including sealed box around it). So food for thought if someone in a similar situation is trying to go uber-cheap.



Appreciate the advice from everyone.

 

[Milton Shaw]

Have you looked at zoneline units, the kind that most motels use. Built in designed with correct air flow inside and outside with divider between outside intake and exhaust air so it doesn't breath the same air and overheat. They also have heat strips or you can get heat pump types. Easier to install and cheaper than mini split systems. Most window units will not have the correct air flow installed in a wall that would be blocking the air flow since the wall is 6" thick not just 2" that a window would be. Compressor would be tripping on over heat all the time and system would not be cooling either.

 

[mpire]

I have seen the mini-splits for as low as $600, so maybe they are still in your budget.

 

[Steves32]

For air intake maybe ill just crack the interior house > garage door an inch when cooling it down initially. Should note this unit has an intake port that looks like you can hook a pipe up to, and in theory I could pull intake from the exterior through another pipe/duct. However pulling the cooler air from the room should cool it faster, so I'll probably stick with the door as the intake exhaust.

If it has provisions for 2 pipes, by all means- run both pipes to outside & close the garage door. It will be far more efficient to cut down on the infiltration.

 

[mpire]

I am definitely no a/c professional, but I do have quite a bit of experience with the portable cooling units. They get used rather often to supplement cooling in the server rooms that I spend the vast majority of my life in.

The overall impression is that they are total **** and that you should avoid them like the plague. I have personally purchased a couple dozen of them, and none of them can handle sustained cooling, and ALL of them seem to go down hill quickly.

Plus the pipes are notoriously bad for pulling the air in and out of the room and through the heat exchanger.

Most systems that don't have a dedicated raised floor with a huge A/C unit blowing the cold air under the floor seem to have defaulted to a Mitsu min-split unit.

I would recommend that you go with a wall sleeve unit or a mini-split before you venture into a portable unit. If you were an A/C professional and could tweak the machine to keep it running, thats one thing, but otherwise I would run away.

 

[mpire]

The Mini-split I have has a provision for pumping down the coolant back into the compressor unit so you can disconnect the lines.

 

[fiveoh]

Thanks everyone for your input. I got a bunch of free blow-in insulation today which will cover my attic w/ a good +8". I spent 60$ on r13 insulation for my two walls that needed covered. And I bought that 1400btu haier unit linked above from home depot for about 450$. I also got a 20" floor fan that can be wall mounted for 30$ - which should help make a big difference in perceived cooling.

So that put me in my price range (540$).

I'm hoping the 1400btu will be overkill for my sized garage, and can cool it down rather rapidly (only need it cooled when I plan on being out there, don't want to have to wait a few hours first though). I suspect the 1400btu will cool it down from about 90-80*F within 60 minutes. If I didn't want rapid cool down the smaller same model (1200btu) was about 80$ cheaper, but take 15-30min longer for the initial cool down (assuming its non-linear). Also the 1400 unit will work better on my main floor which is fairly open and almost 1k sqft.

I have flexible duct, I'm going to take it and wrap it with r13 insulation to use as the exhaust pathway for the AC motor's heated output, and vent it to an exterior wall w/ dryer vent/dampener.

For air intake maybe ill just crack the interior house > garage door an inch when cooling it down initially. Should note this unit has an intake port that looks like you can hook a pipe up to, and in theory I could pull intake from the exterior through another pipe/duct. However pulling the cooler air from the room should cool it faster, so I'll probably stick with the door as the intake exhaust.

I think that covered about all my questions/plans, and I'll report back how well it works, in case anyone else comes upon this thread wanting to do a similar project.

Other reasons why i went with portable unit:
*I can move it inside the house when not using it in the garage (probably only need in garage on weekends, and maybe one or two random evenings a week). Considering I have a very underpowered, old, inefficient central system, using this to cool the main floor will actually save me money on my electricity bill (10-20 a month).

*it's not permanent, if i move in a few years, i don't have to disconnect the lines from a split unit and recharge it.

*Cheapest option next to the box around the window unit idea (and getting window unit used on craigslist). I chose not to go this route for how bulky and ugly it was. Also it would make it difficult for my wife to move it inside should she want to use it like we would the portable on wheels. However, I'm pretty sure I could've accomplished this idea for 100$ w/ used unit, 300$ w/ new unit (both including sealed box around it). So food for thought if someone in a similar situation is trying to go uber-cheap.

Appreciate the advice from everyone.

Let us know how it works out.

 

[Virgil Cain]

What is your HOA's position on mini-splits? My HOA is against window A/C's but there are many mini-splits supporting third floor conversions here. If they allow them I would guess they really won't notice a window unit installed through the wall of your garage. Just put it on a side of your garage that doesn't face the street and paint the surround to match your house. If it's installed through the wall it's not a window unit any more!

This is how I'd go. Mitsubishi makes a nice family of split systems.

http://www.acdirect.com/ductless_cooling_heating_.php

 

[Frank The Plumber]

I cool my whole house on 2, 6 amp window units. It costs me no more than $100 a month to keep the house livable. I have a 6 amp window unit in the shop as well, cheap and if it fails you buy another for about $120.

 

[Teken]

I cool my whole house on 2, 6 amp window units. It costs me no more than $100 a month to keep the house livable. I have a 6 amp window unit in the shop as well, cheap and if it fails you buy another for about $120.

Frank,

Is that $100.00 a month accurate for cooling? What is the electricity rate in your area?

 

[jimp]

Frank,

Is that $100.00 a month accurate for cooling? What is the electricity rate in your area?

Some peoples livable is a lot warmer than others, I'll bet.

 

[Frank The Plumber]

I have a little house. I cool the upstairs. It's about 75 on a 95 degree day. If I get it too cool I just die in it all day so I keep it sort of warm. I just want it so I can sleep.

 

[Gary S]

First insulate. Then think about air conditioning. My well insulated garage stays at 80 in the summer with no a/c unless we get an unusually long hot spell in which case I fire up my window unit.
If you do a good job of insulating, you can get by easily with a much smaller unit.

 

[flajim]

I cool my whole house on 2, 6 amp window units. It costs me no more than $100 a month to keep the house livable. I have a 6 amp window unit in the shop as well, cheap and if it fails you buy another for about $120.

I'm just adding to this example to restate that good insulation is key. I live in a 30 y/o house and remodeled 5 years ago. Replaced/improved all insulation in all walls and ceilings and replaced doors and windows. I have the same A/C as before remodel (it's 10 y/o now). 5 yrs ago, I paid $250-$275/mo electric in the summer and $150-$170 in winter and spring.

NOW, with improved insulation/windows/doors being the only change, I paid $87/April '11, $102/May '11, and my bill for June yet to pay is $113. I live in Florida and keep the thermostat at 72* 24/7 and we've been at 90*+ outside for a month now. My winter bills are $70-$80. I haven't paid $125 in 5 years.

That was quite a welcome improvement. My garage is 30x50 and I am currently well-insulating the 20x30 room I built inside. Insulation is a worth-while investment.

 

[Frank The Plumber]

If you insulate your attic make sure you put some roof vents and or a ridge and cobra vents into it.
The trapped heat will elevate the temperatures and cause the shingles and roof surface to age rapidly, and the home temperature to rise. The real trick is good airflow in the layer to dissipate the heat.

 

[Duane]

I bought an Alen Mini split for that price and it works great. Very Quiet too.

Duane

 

[Chris05gto]

Can a home owner install a Mini Split?

 

[rickairmedic]

Can a home owner install a Mini Split?

Sure you can install it but you will still need to have a tech come out and pull a vacuum and do initial startup on it and sign off on it or you will have " NO WARRANTY " on it .


Rick

 

[GDA]

Thinking outside the box here....

Could you build a small lean to shed directly up against the garage and then hide the outside of the window unit AC internally in the shed?

 

[welder4956]

One of these portable cooling units might be worth checking into. Looks like you just need to run an exhaust duct to the outside.

http://www.movincool.com/portable-air-conditioner/pc7.php