I turned my garage into a man cave. Put carpet in the whole nine yards. I put a 14,000 btu portable air conditioner in and ran the exhaust through a hole in the side wall. I've had the unit for 3 days. During the day the temps outside have been 90-98 degrees. And the unit has kept my garage around 70-73. But at night when outside temps drop to 65-75, the brand new a/c unit will stop cooling down the room at 68. And it starts to smell musty or really humid like. It is still blowing cold air, but I like it really cold. My central a/c unit for the house has no problem keeping my whole house at 65 all day. Why isn't my garage A/C working?? The humidity levels have been about 60% and not fluctuated much. Why won't it cool past 68, when outside temps are about the same? It is a single car garage. It is set at 65 and I can hear the compressor running, and ir temp gun shows its pushing out 49 degrees.

 

Is this a single duct or two duct portable A/C? The one duct just don't cool as well as the two duct because they exhaust some of the chilled air outside to cool the condenser and in the process of blowing the chilled air out they draw warm air in to the area to make up for the exhausted air. On the other hand with a two duct model the air to cool the condenser is drawn from the outside through the second hose so the cold air is constantly recirculated getting a bit cooler each time. That said I'm not sure 68° isn't about as cool as you can expect but the A/C pros will have to comment on that.

 

Sounds like the AC is working fine. If you want it colder you will need a bigger unit.

 

Need to find out what is the unit's cold air temperature when you said it is working, and also when it is not working. I am guessing the compressor stops running when the temp reaches 68 degree.

 

Possible that the coil is starting to freeze up at that temp or there's a limiter shutting compressor below 68.

65 is freezing, why not just get used to the higher temp?

 

No one know's where you are since there's no location in your profile.
How much insulation is in the walls and ceiling?
Old leaky windows?
http://www.doityourself.com/forum/ai...past-68-a.html
I have to agree, just can not imagine needing it that cold.

 

Sounds like you have a humidity problem. How does this a/c unit get rid of condensate?

 

I agree its a humidity issue. If it were dry and 68, I don't see how that isn't comfortable, though 68 and humid would feel cold and clammy.

If unit is oversized, you will have higher humidity and probably limit how cold it can get. Higher humidity means you can do less actual cooling. You lose capacity to the water running down the coil...

This may be why you hit a wall at 68. Unit may limit how cold the coil can get. If its humid, you will not get same temp drop.

Bigger is not always better with AC.

If you are covered in sweat and enter garage, do you dry off quickly or get cool and damp?

You are on the fringe of needing a refrigeration system, not AC.

 

In less than two hours it will have been a full week since Andrew has been logged in. I think it is safe to call him a "One-Post-Wonder".

 

Id be willing to bet the garage doesn't have a VB under it. He will never get the RH down.

 

I remember when I had a portable AC unit. I am not a big fan of them.

Every two hours, you have to empty the condenser pan, otherwise, it will stop operating. Also, it was so loud. I also felt that the cooling was not that effective. I ended up returning it after 3 days.