Air conditioner not cooling house below 77 degrees during the day in 100 degree weather is that normal?

My a/c won't cool the house below 77 degrees during the day. I had a company come out and said the air coming out of vent is 56 degrees and air going in is 75. He said nothing is wrong with my system its just so hot outside. It has been in the 100's for 16 days straight. Is this true?


I've never noticed before but I think it's because I upgraded to a digital thermostat and it may be more noticeable because I see it everytime I go down the hall. Thanks for all the replys. Saved me the cost of a second opinion.

11 Answers

  • 8 years ago
    Best Answer

    Yup it's true. Your AC unit cannot keep up with how freakin' hot it is outside and your house's inability to insulate against the heat.

    I live in California and my AC does the same thing. It finally gets really cold in at night. On forecasted hot days, we turn on the AC long before it actually gets hot. This helps a lot, but eventually the interior of the house will get to 80 when it's over 100 outside.

    Hope this helps.

  • 5 years ago

    If it's 100 degrees outside, 77 is EXCELLENT ! An ac system can cool your house no less than about 20 degrees less than the outside air temperature. The air coming out of your ducts is probably around 68 degrees and the rest is lost to insulative factors.

  • 8 years ago

    Yes, it sounds right. The higher the temperature is outside, the more heat will transfer into the house. This greater heat load may then become too great for the AC to cool down below a fairly warm temperature like around 75-80 degrees.

  • 8 years ago

    One of the things you also have to realize is that if your dewpoint is 77, your air conditioning will have to work even harder. One thing that happens is when you reach the dewpoint, you begin to condense water. Condensation requires a lot more energy than cooling air to that point, and it is a exothermic process, releasing heat energy, which in turn is dispersed to the atmosphere. I would say take a look at your A/C unit outside. If you see a lot of condensation or (if a window unit) is dripping, chances are you aren't going to get much cooler in the house.

    (Aside: I'm presuming you are one of the people in the Eastern two-thirds of the US, where dewpoints have gotten up to 77 or above in many areas from Minnesota to New York).

    Source(s): meteorologist/climatologist; also look up "latent heat of vaporization/condensation" if you want more details on where I got my answer.
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  • Anonymous
    8 years ago

    Yes that is absolutely true.I put mine on around 5 last night and it took 2.5 hrs to go from 86 to 80 and then it wasnt till around 10 before it went to 75.Still made sleeping a lot more bearable than having no air at all.

  • 8 years ago

    It sounds right to me - the output of your system just isn't strong enough to combat the excessive heat. There's also a good chance you have substantial leaks around the house.

    I would try to keep your house as warm as possible to go easy on your AC unit - ours is set at 81 during the day, 83 at night. And yes, we're currently at 106. Yucky.

  • 5 years ago

    I was having humidity issues with a BRAND NEW unit...Outside temp is 95 and the unit said 78 and it was incredibly sticky and humid indoors....The tech cleaned my water lines and amazingly it feels much, much better....It still registers 75-78 degrees but more comfortable!

  • 8 years ago

    Sounds like your house is not insulated very well. You may also have a lot of windows that is causing convection heating. Try covering your windows or closing the curtains. Sounds like you AC unit is working fine, just many other unknown variables to me to say exactly why it's not keeping up to your request.

  • 5 years ago

    i need some cold air to come out i have warm air coming out of my 5000 btu airconditioner by haier but i had the airconditioner on its side in the box never opened nd when i looked at the box it said keep upright could that be it...i need help it s

  • 8 years ago

    it could be true if your home is poorly insulated and therefore not keeping the cool air inside. If so, you are basically paying to cool the outdoors.

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