Cooling a 28x28x16 garage

[CobraJake]

So new to me house last year and I'm beginning to find the flaws that need attention. I installed a Hawt Dog heater over the winter which was great and kept the temp up to par. Now with the last week over 90 degree's, the back wall has begun to sweat pretty good mainly in the back bathroom area. What would be a good fairly cheap alternative for this year and maybe next? 2 portable a/c units? No windows in there and alot of concrete.

and what about in the future...something more permanent?

 

[Cryptic1911]

pick up a cheap ductless split unit?

 

[Warrenator]

I also vote for a mini-split, only need a 2" hole to run the refrigerant tubes through. Can get them cheap online.

 

[CobraJake]

Edit: what's a good brand for the mini-split? I just read up on them (had no clue before) and like the idea but with the main problem area being the bottom corner and this unit being way up will that matter?

 

[Jackfre]

Yes, it does matter where you position a mshp on the wall. *' is about the max you want above the floor. Otherwise you end up with the unit sensing a different temp that you want in the space. Keep in mind that the actual sensing point (t'stat) is in the evaporator. It can get frosty low down while the unit, due to stratification of air is just happily hammering away. Check the spec on whichever manuf you choose.

 

[CobraJake]

Yes, it does matter where you position a mshp on the wall. *' is about the max you want above the floor. Otherwise you end up with the unit sensing a different temp that you want in the space. Keep in mind that the actual sensing point (t'stat) is in the evaporator. It can get frosty low down while the unit, due to stratification of air is just happily hammering away. Check the spec on whichever manuf you choose.

how far above?

does it have to be installed on an exterior wall? if thats the case the lowest it could be in there is about 8' up

 

[Highbeam]

No, it can be on an interior wall but you will need to deal with the condensate by pumping or draining into the building.

 

[pseudorealityx]

To cool a such big garage you need a big chiller, It would be expensive but easily chill your garage. You can also use splits but the cooling will be normal.

No no no no.

 

[CobraJake]

To cool a such big garage you need a big chiller, It would be expensive but easily chill your garage. You can also use splits but the cooling will be normal.

It doesnt need to be 50 degree's? I would imagine normal cooling would be fine

 

[sands35]

how far above?

does it have to be installed on an exterior wall? if thats the case the lowest it could be in there is about 8' up

With ceilings that tall, you probably want ceiling fans anyway just to move air around. That said, heat rises and cold sinks, so mounting a ductless evaporator higher shouldn't be a problem.

AC sizing is the same, just some online stuff assumes 8-10' ceilings. Just double check the calculators on what ceiling height they are using. Some go by floor square feet, some go by room volume.

If your priority is humidity control, then you will want it to run more often, so a slightly smaller unit for your volume. Given that, it might be worth a call to a local installer with a decent reputation - and somebody who will actually do the right math AND share it with you so you know they are actually thinking through what needs to be done.

You have a plumbing stack on the interior wall, so that would work for condensate.

 

[CobraJake]

With ceilings that tall, you probably want ceiling fans anyway just to move air around. That said, heat rises and cold sinks, so mounting a ductless evaporator higher shouldn't be a problem.

AC sizing is the same, just some online stuff assumes 8-10' ceilings. Just double check the calculators on what ceiling height they are using. Some go by floor square feet, some go by room volume.

If your priority is humidity control, then you will want it to run more often, so a slightly smaller unit for your volume. Given that, it might be worth a call to a local installer with a decent reputation - and somebody who will actually do the right math AND share it with you so you know they are actually thinking through what needs to be done.

You have a plumbing stack on the interior wall, so that would work for condensate.

Well my primary concern is moisture / humidity. the back of the garage is wet which got all my stuff wet. Its 76 degree's in there which isnt bad but no circulation. ive had the two ceiling fans on for 2 weeks now. They helped a bit but not enough.

That stack on the left side now has a Hawt Dog heater on it

 

[Highbeam]

To cool a such big garage you need a big chiller, It would be expensive but easily chill your garage. You can also use splits but the cooling will be normal.

This man's shop is similar in size to a regular home and easily cooled with minisplit technology. Pretty typical to have a 28000 btu unit and if you put two of them in then you have the horsepower. No need for some huge chiller.

 

[CobraJake]

This man's shop is similar in size to a regular home and easily cooled with minisplit technology. Pretty typical to have a 28000 btu unit and if you put two of them in then you have the horsepower. No need for some huge chiller.

what brand are you using?

 

[Highbeam]

what brand are you using?

None in the shop, radiant floor heat in the shop. A btu of cooling is a btu of cooling. How many do you need for the load?

 

[CobraJake]

None in the shop, radiant floor heat in the shop. A btu of cooling is a btu of cooling. How many do you need for the load?

no clue...thought you said above you have a huge shop cooled by mini splits....

 

[mrgm]

set up cheap in wall circulating fan for that back room on one side to your open garage space, other side of room install transfer grille. get a temp sensor and set it with system also add carbon monoxide alarm in room if it opens to house.

cheap

 

[mrgm]

ohhh and finish the ceiling

 

[CobraJake]

set up cheap in wall circulating fan for that back room on one side to your open garage space, other side of room install transfer grille. get a temp sensor and set it with system also add carbon monoxide alarm in room if it opens to house.

cheap

ceiling is now finished

but there is no wall to the open garage space...just the door....all the concrete you see is underground. maybe should have specified that

 

[larry4406]

My garage in northern VA is pushed into a bank on two sides. The earth moderates the temperature quite well. If yours is indeed underground and in Massachusetts, I would think you would experience similar.

A dehumidifier and circulation fan works wonders. Keep the main door closed as much as possible.

I have a 5 ton AC unit (overkill), but the dehumidifier is more than adequate.

 

[CobraJake]

My garage in northern VA is pushed into a bank on two sides. The earth moderates the temperature quite well. If yours is indeed underground and in Massachusetts, I would think you would experience similar.

A dehumidifier and circulation fan works wonders. Keep the main door closed as much as possible.

I have a 5 ton AC unit (overkill), but the dehumidifier is more than adequate.

it was great until we had a wave of 95+ degree days w/ high humidity. the main door wasnt even opened for 3 weeks!

here is the outside...its like this on both sides

 

[Jackfre]

eight ft for the high wall units.

 

[oilman2013]

use a split system no less than 20,000 btu put your condensate line to the outside wall let it drip out there dont go to the expense of a pump its no value to you . for the time being get a dehumidifirer and let it run 24/7 to get rid of the humidity , leave your fans on too that will help circulate the air . even when you get your a/c use the fans they will move the air in the room . put the a/c unit up on the wall about 5 feet from the ceiling that should work the best for you . oilman 2013

 

[TimRogers]

On a related note, after adding 75% more soffit vents, insulating the walls with fiberglass and turning the peaked roof of my 24 x 36 attached garage into a peaked, insulated ceiling via foil backed foamboard:

The garage does have a screened door and window on opposite sides so by running some window fans overnight, I can bring the interior temp down to near ambient at daybreak.

I'm ready to pull the trigger on a mini-split system w/ inverter and feed the existing 240V to it. My question to anyone with an informed opinion is: should I get a wall mount to go where the ceiling meets the wall, a ceiling mount to go in the middle of the open cross-beams, a ceiling mount to place at the peak of the ceiling or is there another, better option? I was thinking of 18,000 BTU to deal w/ our Atlanta area heat & humidity - will that be enough given the extra head room of the ceiling area?