I live in a 2nd floor apartment (660 square feet). My A/C unit will run anywhere from 45 minutes to an hour and a half to cool my apartment 1 degree. The unit is definitely cooling. When it is on it feels much better in the apartment I can tell that it is getting more comfortable. I normally keep the apartment at 77 degrees. The unit is running that long just to maintain 77. I'm not asking it to cool 5 degrees. This is just to cool from 78 to 77. I think that this is I live in a 2nd floor apartment (660 square feet). My A/C unit will run anywhere from 45 minutes to an hour and a half to cool my apartment 1 degree. The unit is definitely cooling. When it is on it feels much better in the apartment I can tell that it is getting more comfortable. I normally keep the apartment at 77 degrees. The unit is running that long just to maintain 77. I'm not asking it to cool 5 degrees. This is just to cool from 78 to 77. I think that this is way too long for such a small apartment. I can hear my neighbor's units and they only run for 10 minutes at a time. The maintenance people have been to my apartment 3 times. They say they have recharged the coolant, fine tuned the part of the unit that takes the humidity out of the air, and replaced the thermostat. They say that the air coming out of the unit is plenty cool and that the "differential" is good. But it keeps running for an hour to cool 1 degree. I'm not running any heat making appliances in the apartment and the weather in my area has not been all that hot. This morning it was 60 degrees and low humidity outside and the unit turned on to cool down 1 degree and ran for 57 minutes. I find it kind of odd that my neighbors' units run for 10 minutes every time and my unit runs for a different length of time every time it turns on.

Am I just expecting too much or am I right in thinking something is wrong. Do you have any ideas of what might be causing the unit to run so long to cool 1 degree? I am getting really frustrated and appreciate your help.

Is there an apartment above.

Go see what your neighbor is doing that's different than what you are. His windows may face a different direction than yours and get less sunlight, or he keeps his curtains drawn, or maybe he sets his thermostat higher, or you have "hotspots" in your apartment, who knows? There are so many factors that can go into this, that it's very hard to say if you have a problem or NOT.

Maybe you need an evaluation from the utility company. Where in the world are you? Are you in the US? Where is your thermostat in relation to doors, and windows?

Yes. There are three stories.

My neighbors have the same number of windows that face the same side of the building and get the same amount of sunlight. I keep my curtains closed all day. I find it hard to believe that they are keeping their thermostat high enough to make a difference (77 degrees is pretty high. I don't know anyone that keeps their's lower). I am in the US and my thermostat is as far away from the windows as you can get in the apartment.

Take a temperature reading at a supply duct and at the return. Should be at 15* degrees difference or higher.