[stockups]

Hi all I need some advice as you all know it been in the 117s here for the past 5 days. Here is my problem I set my downstairs AC for 76 but for some reason I cannot get the inside Temperature to go below 79.
We do have high ceilings also I check the vent air and it is reading 70 coming out of the vents any help in this matter would be grateful

Sincerely Michael

[Everdeen]

I really am no expert, but it is probably the excessive heat. Our other house high ceilings and I think that affects it too. Maybe your AC is not built to handle the square footage? That's also the case with my other house.

[Scott456]

1. check if there is any leak in your vent line.
2. As the previous poster mentioned, your AC may not be enough for your square footage plus the high ceiling.

Let us know what you find out.

[MollieW]

If your square footage is over 2,000, you usually need a second unit

[stockups]

no my home is 1776 we have a second unit for the bedrooms upstairs the bedroom and upstair bathroom doors are close we are talking about 1100 sq feet down stairs

[Kaiminani]

There are like a million things that could be the problem.

First of all, does your AC run continuously? If it is stopping before it gets to the setting, then your thermostat is probably broken.

If it is running 100% then it might be too small, or it just might not be working optimally. Here's some possibilities:

1) Ducts are leaky - get them sealed up (do not use duct tape)
2) Ducts are in the (hot) attic - wrap them with insulation
3) Compressor is low on refrigerant - get more refrigerant, check for refrigerant leaks

If it is too small, there are some things you can do to reduce the amount of heat it has to cool away:

1) If lots of sun is coming in the windows, get solar screens put on the outside of those windows
2) If lots of heat is coming through the windows (it is noticeably warmer right next to the windows) but not much direct sunlight, get thermal drapes from walmart/target/bedbath&beyond/etc
3) Check for air leaks around the doors and windows with the smoke from an incense stick, if you have leaks, seal them up with caulk or weather stripping
4) If your roof is dark colored, paint it white. 50 bucks for lime, a waterhose, a big broom and some elbow grease will be enough to get the job done and it will last through at least a few rainstorms
Experiment With White Roof Cooling Effect

There are lots more things you can do, most are more expensive.

[tiger08]

70 degrees out of the vents is way too warm! You should have at least a 20 degree difference between return and supply air.
Have someone come out soon and check to see if you are low on refrigerant, or if you have another problem. Low refrigerant or a bad txv valve can also cause compressor failure, expensive!!

The fact that your able to maintain 79 in the house with that warm of a supply temp, tells me that you have good air flow and the house is probably insulated quite well.

[Scott456]

Originally Posted by tiger08

70 degrees out of the vents is way too warm! You should have at least a 20 degree difference between return and supply air.
Have someone come out soon and check to see if you are low on refrigerant, or if you have another problem. Low refrigerant or a bad txv valve can also cause compressor failure, expensive!!

The fact that your able to maintain 79 in the house with that warm of a supply temp, tells me that you have good air flow and the house is probably insulated quite well.

Getting a technician to fix the AC in the middle of the heat?
You can expect a outrageous price !

[KKVegas]

Last year during the hottest part of July, our air conditioner ran almost constantly and just couldn't seem to keep up with the heat. Even though the thermostat was set to 76, the temperature in the house would sometimes get to over 80. When the temperatures were under 105, the air conditioner worked fine.

Anyway, this year the old air conditioner finally broke (it was 16 years old), and we got a whole new system. Now, even at 117 degrees outside, it's 76 inside. The new air conditioner is the same size as the old one. So in our case, our old system was just wearing out I think. This is not to say that is your problem, but the difference between the old and new systems for us is substantial.

[stockups]

tiger what do you mean by You should have at least a 20 degree difference between return and supply air. how do you check the suppy air