I have a 18,000 btu window unit in my basement.I like it cold and nothing gives instant gratification like a window unit.I leave it running awhile and have noticed something.It blows 42 degree air.After its been on a while it goes up to 60 degree.If i mess with the thermostat turning it back a little and back to max you can hear the compressor kick in and the temp goes back to the low 40's.Is this normal?Most of the time I shut it off for a while and that works also.When we bought the house it didn't have central air just this in an upstairs window.In June one year we had a Birthday party for my son it was about a 100 out I turned this on and left it I came in about 4 hours later and it was 66 degrees in the house.About killed my wifes grandma who didnt or never will have air she says its to cold.I just dont think its working as good as it used too.

I had a similar problem with a small window-unit A/C and it ended up being ice formation on the condenser. Apparently the ice messed with the air flow and resulted in inefficient cooling.

I'm not an A/C pro though, so I have no clue. =D

It's totally normal for it to do that. All that is happening is that your air conditioner's internal thermostat is kicking your compressor off, when the tempurature rises about 2 to 4 degrees the compressor will kick back in. When you move the thermostat all it's realling doing is bumping the compressor back on for a moment to get it down to 66 since the thing thinks you have set a new temp that it needs to meet.

Jake

When a central AC reaches the desired temp it shuts off, [b]fan[/b] included.
Window AC's are different, in just the compressor shuts off, but the fan keeps running. Most new window AC's have an energy saving feature, which gives you a choice of the whole unit shutting off when the thermostat is satisfied.

Forgot to say this is a 1985 Carrier unit.

1985 Carrier...

Probably needs a recharge... (similar thing happened to my (former) car's A/C).

One problem: the Govt banned freon production (with good reason).

Time for a new window A/C...

Dave I hate to rain on your parade but:

No, it doesn't need a recharge.  If it can get cold, charge is fine!

Gov did NOT ban "Freon" production!  Freon is a brand name owned by Dupont.  They still make products branded Freon.  Production of R-12 and R-502 REFRIGERANT (among others) was banned.  But NOT for good reason!!  Damn Junk Science in fact!!!!!!!!

In any event, a window unit uses R-22 REFRIGERANT which is NOT restricted except as to who can purchase it.  

NOT time for a new unit!!

You learn something every day... (Window AC from 85 not using R-12)...

And yes, I should have said 'R-12', not freon, but... oh-well...

All my AC-experience relates to fixing the problem I had in my car. I had it cleared, and put R134 in it (with a kit). Since I didn't know if you could charge window A/Cs (the one we used to have before we went central was sealed shut), that's where the 'replace' comment came from...

Oh well, good luck

Thank God most window units are "sealed" system.  Keeps most people from screwing with them, and screwing them up!!

Some idiots insist on installing mechanical "tap valves" which INVARIABLY leak, even if the unit did not do so before!  If you must "tap" one (avoid if possible) get someone smart enough to silver solder access valves to the process stubs!!!!

What DrFridge said is most important!!!!  Good water flush of condenser (outdoor coil) is a necessity as well.  They get ignored and bake on an unbelievable array of crud.  Result is poor cooling, high operating costs and ultimately destruction of the unit.  Give it a bath!!!

Dave, I can see how we came to disagree.  Cars, window units, residential central units and refrigeration are all very different branches of the HVAC/R trade.  The theory is the same but the technology and it's application are far different.  Had a few beers here and just felt the need to clear up some misinformation.  And yes, I do this for a living!