I have a small shop that I work out of, and it is really, really hot in there this Texas summer. It is a 20x22 single garage-style unit, with insulation in the walls behind light paneling, but no insulation in the rafters anymore. The building is surrounded by trees, but the sun beats down on the roof all day, and the south door gets sun on it all afternoon.
I have a 11,500 BTU 110AC window unit air conditioner mounted in the north wall. I can start it up at 8am, and let it run all day, but by 1-2pm, you better be in front of a fan if you want any relief from the heat. By 3-4pm, it can barely keep them temp down to 95 degrees.
Now, it gets so hot by late afternoon, that the compressor on the A/C kicks off and the unit will not cool or cycle.
I used to have an old 1970s unit in the same place, and it basically had an ON/OFF switch, so it would run, even if it couldn’t cool the place down. The current A/C (only about a 4 year old model) decides if it will cycle or not, so it justs blows hot air when it’s really hot.
Does this newer unit have some kind of limiter on it? Is the thermal load just too much for it? I don’t expect my shop to be nippy on a hot Texas day, but 11,500 BTUs for 440 sq/ft should make it bearable, right?
Then again, the central A/C is my house is running all day and it barely keeps the inside at 84 degrees during the day.