a/c not cooling enough

my a/c is not cooling enough, it's running and blowing cool air but not cold enough to maintain the temp. inside the house. the thermostat was set @ 78 but it went up to 85 and it never cut-off again so ihave to stop it since itwas now almost 6 hours. i inspected the unit and there was some condensation along the wrapped cooper wires. pls give me some ideas on whats wrong with it so i won't get rip-off on repairs.. thanks

 

You have described a perfect example of:

Low refrigerant charge
Dirty Filter
Broken or leaking ductwork
Dirty evap coil
Dirty Condenser coil
Restricted filter drier
or
All of the above.

I'm sorry, but without better defined symptoms, we can only guess what the problem might be.

 

first things first. If you have a meat thermometer or other thermometer that measures from say -10 degrees to 300 degrees(ussally available at a grocery store in the kitchen equipment aisle for about $5) measure the temprature of the room and then the temprature of the air coming from the registers. Preferable the register closest to the air handler or furnace. Let us know and we can better help you.

 

thanks for your ideas, this i what's happening now:
1. the outside unit has a paddle of water @ the drain pipe
2. the condenser unit has water(evap) on the cover as well as the pipes that come out of there leadind to the drain pipe.
3. a/c cannot handle the 75 setting during the day(esp. midday when it's hot/humid) but at night it can, and in the morning there's a lot of water on the unit and surrounding
4. when i put my hand on the vent to feel the air coming out, it felt cool but it just takes a lot of time to cool the whole house i think it's eating a lot of energy
5. the sound of the unit running was normal as usual but there is more watery sound on the condenser

my co-workers told me that it probably needs freon(it hasn't been added in 5 yrs) and also it could be that the condenser unit has frozen and suggested i shut-off the unit for half a day to thaw. just give me your best opinion and what range am i looking for repairs so i won't get rip-off.