My central air doesn't get cold enough.?

Question

It is new and it does have some cold air coming out. I have the temp set to 74 but by 4:00pm it is up to 79 to 80.

Answer 1

If the temperature it cools to is atleast 20 degress less than the outside temperature, it's working fine. It can't be expected (if it's a normal household central air unit) to cool it down to 74, when it's 100 or so outside.

Now if it's only 85-90 outside, then you have a problem. Have you changed your filters lately? Should do it every 60 days at least (90 is probably too long)

Answer 2

There should be a 20 degree drop across the cooling coil. If air enters at 80 degrees it should exit at 60 degrees. If the air out of the vents is 15 degrees cooler than the house temp then it's probably close. Here are some tips:

A. The people that installed the unit should have studied your home and computed heat gain, then size the unit accordingly, they should not have guessed.

B.Get yourself two of those cheap thermometers with the wire(thermocouple) that you run out a window to read outside temp. Put one of the thermocouples down in the vent. Put the other thermocouple the same height in the room as a thermostat would be. If the wire for the thermocouple is long enough and it is a unit that reads both inside and outside temp, than you can just use that. If the diference is 15 degrees or better than it is close. If not, then the unit is probably undersized for the extreme conditions or you can try and address any or all of the following.

Call service to clean the coils and check refrigerant charge.

1. Is the condenser unit outside set in the sun? Yes, then provide shade for the unit. The sun is just making it harder for system to remove the heat.

2. Is your home well insulated?

3. Do you have proper ventilation in your attic spaces?

4. Close the blinds, curtains, etc on all the windows. If you don't have blinds or curtains install them. Light=Heat.

5. Turn of sources of heat you really don't need like high wattage lights, etc.

6. Limit cooking inside

7. Install warm air returns if possble.

8. If you have a basement close the door to it. No door, install one. Cold air falls.

9. Improve your landscaping to provide proper summertime shading of the house.

10. I've heard of people setting a mist sprayer near the condensor to get some evaporative cooling of the refrigerant. What affect this would have on the unit in general, I don't know. Mine gets exposed to rain so I figure whats the difference. This is basically how a cooling tower works.

If you still can't get the temperature down in extreme heat then you may need to add additional cooling capacity to help with the extra load. I've seen homes in warm climates with two separate units. The second kicks in when needed. You don't want the unit to be oversized for normal cooling loads or it wont remove humidity properly.


We have extreme heat today and even our commercial untis for our building are having trouble.

Answer 3

Do you have proper ventilation in your attic?

Right now, I have our thermostat set on 75 and in the inside temp is 79, it was recharged during the winter time (cheaper) and has a new compressor. My husband and I were at a stand still trying to figure out what on earth was wrong. I went around all of the windows and doors with candles to check for leaks, there were none. I said hmmm, what about the attic, maybe it isn't insulated well. Well, we climbed up there, and there is absolutly NO insulation, and will it does have gable vents on the sides, there are no fans. We put a box fan up there this weekend, and it actually brought the temps down a few degrees, just by moving the air about. This weekend we are buying some gable fans, which move about 1600 cubic feet of air a minute. Hopefully that will work.

But I would check your attic for sure. You might want to do it late in the evening, it will be very hot up there.

Answer 4

It might be low on freon. Have a professional heating & air conditioning company service the unit. The filter can be clogged or full, even if the unit's new. Filters should be changed every 3 months, just like the air filter in your car. You're also wasting electricity with the temperature that low. Turn it up to 78 or 80 & use fans in the rooms to help circulate the air.

Answer 5

i have to clean my ac filter once a month, do you do that, it will help keep the dirt from clogging it.

also could it be freezing up on you. but i would have tech look at it. to make sure what the problem is, and get everything in writing for what the tech says is wrong, and i would get two or more inspections, we just had a documentation on the news here about ac techs ripping people off.

good luck, 79 to 80, heck that is cooler then our over night temps which stay on the 90's since the monsoons have came in it has cooled us down a little.

Answer 6

My dad just had his unit replaced last year and ran into the same problem. The ducts in the attic were not sealed properly so the cold air was seeping out of them and never making in to the rooms to cool. The company that installed in came back out and corrected the issue....finally!
I suggest calling them and explaining the situation. It should be under warranty. If you don't get satisfaction there, contact another company to come inspect it and send the estimate to the original company. That will light a fire under them!

Answer 7

Needs the Freon filling up

Answer 8

The installer needs to diagnose the problem. There can be several reasons it isn't cooling satisfactorily. All of them too complicated to meaningfully list here.

Answer 9

You may need to call a service rep..Sounds like things are siezing up or it needs freon....Are you having brown-outs in your area? If so that could be why..the electrical company does that to save on energy.

Answer 10

clean the filter and spray off the outside unit with water hose