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taylorneatherlin

General A/C Question

9 years ago

Greetings. I am a first time homeowner so I am a bit naive on this subject. Anyways, here goes -- I moved into my home a week ago and the A/C was out. No home warranty so I was on the hook. Called a technician and it took him 5 minutes to determine fan motor was out. Fixed that and that really helped the unit! My concern is there may be additional issues as well. The previous owners appear to have not done much upkeep with the unit. When I moved in, the filters were filthy which I immediately replaced and the condenser was full of dirt.


The A/C has a really hard time getting below 78 degrees during the day (I left it on 80 today since I felt like it was running a lot while I was at work) and 75 is the temperature I have found it works best on at night. I live in Texas and our daily highs can get well above 95. I also have a lot of windows and skylights in my house. Is this normal? Any input is greatly appreciated!

Comments (17)

  • 9 years ago

    Energy Star recommends: 85 when at work, 78 when at home, 82 when sleeping.

  • 9 years ago
    last modified: 9 years ago

    No, it's not normal. If you're looking for more detailed info then this HVAC contractor forum might be able to help with that.

  • 9 years ago

    Well crap. I asked the technician after he installed the fan if there was any other issues he thought needed to be addressed and he was adamant that there was not. Even after I told him the situation i described above he reiterated that he did not think there was anything wrong with the unit.

  • 9 years ago

    You would think it would be in his best interest to identify additional issues

  • 9 years ago

    A properly designed HVAC system should be able to maintain a 75 degree indoor temperature during the day when the outside temperature is at the typical summer high temperature. it may struggle if you are in the upper 90s or over 100 degrees.

    Windows and skylights increase the cooling load so it could be the HVAC system is undersized. I recommend you hire a competent HVAC tech to do a full preventative maintenance check on your system. This includes verifying the refrigerant level, measuring voltage levels, and hosing down the outside condenser so air may circulate.

    You should drawn the blinds on south and west facing windows to help reduce the cooling load, You should also consider installing retractable shades for the skylights. You will be surprised how much this will help.

  • 9 years ago

    Thanks, Mike. Those are really good suggestions and I think I will go ahead and order some blackout curtains before calling another technician out

  • 9 years ago

    Welcome to houzz taylor, I recommend asking your utility company to preform a FREE energy audit?

  • 9 years ago

    TX gets hot, and humid depending where you're located. Both put an extra load on the system. I've seen systems, even in newer construction, sized on the edge of adequate such that mid 90°Fs and higher they can't maintain an indoor temp lower than 78°F (and up depending on how hot is the weather). That's not a reasonable situation but it's not uncommon.

    Jim Mat, there's no way I could be comfortable at 82°F for sleeping ... without considering that the body sleeps better when cooler.

  • 9 years ago

    Ditto dadoes. 82 is way too hot for me to sleep at also.

  • 9 years ago

    HVAC is usually sized to typical summer temperatures, not extremes. I would want to know that refrigerant charge is corrrect and delta T. Age of your system?...what supply temperature are you getting?...

  • PRO
    9 years ago
    last modified: 9 years ago

    I service the Katy, Texas area 832-475-6895

    To the OP: here's something simple you can do to see how well the performance is of your HVAC system.

    Take a temperature from the return. If the thermostat is located near the return and it's a digital stat you can just use that number.

    Then take your digital thermometer and place it in a supply vent. Record that temperature.

    The temp near the return will be the higher of the two. Subtract return temp - supply temp.

    What is the number? We shoot for 15-20 degrees temp drop across coil.

    The closer you are to the 20 degree mark the better the performance of your AC.

    Which means the system may be doing all it can do and you have other more complicated issues as to why the system doesn't perform well. It could be poor ventilation in the attic, lack of insulation, thermal envelope breaks and so on.

    Never, never assume the system is too small for the building. More often than not the systems are oversized and have systematic problems as to why they aren't performing well. Increasing the system size in an older home is rarely a good idea. 90% of the time a single speed air conditioner runs, it is over sized. Heat of the day is between 3-6pm and more extreme heat waves 3-7pm most of the time the AC is sized right 1/8 of the day in a properly sized HVAC system. Because of this... upping the size of the system will make things worse.... the cure for that is to rip it all out and redo it again.

    People who recommend sleeping at 82 degrees? You probably live in Arizona huh?

    I sleep at crisp 74 zoned - your cares melt away at this temp. The rest of the house is off... as it's not used at night.

  • 9 years ago

    Austin Air -- I'll be sure and get a reading when I get home from work. I did a bit of testing yesterday evening. I clocked how long it ran/was idle at 80 degrees. The outside temperature was around 87. On average, it ran 48 minutes and was off 12. Basically, it ran 80% of the time. After I tested this, I put it on 72 to see how many degrees it would cover in a hours time. It dropped from 80 to 79 in a hour.


    Something is definitely wrong. I think I am going to go ahead and get a second opinion. Thank you all for your insight -- this is so frustrating

  • 9 years ago

    You didn't say how old the equipment is.

  • 9 years ago
    last modified: 9 years ago

    Ok fellers,I can assure you that taylor is either dead from Texas heat or was never invested in finding a solution. 18 days ago Austin Air gave Taylor a simple test that Taylor promised to perform and report back. Anyone heard from Taylor since?

  • 9 years ago

  • PRO
    9 years ago

    I have to continually ask myself if I am still alive in this heat.

    In Texas we have two seasons... Summer & August.

  • 9 years ago

    Then I won't tell you that we're in the 70's all next week. Almost autum!!!