The last 3 days my ac has been running a lot and the house has been really cold. At first I though it was just because it was so humid outside and it just felt colder than it was.

The thermostat is set to 72 and I finally got out my Weber grill thermometer and it read the house temp was 66. Does that mean my thermostat temperature sensor is out and I just need to replace the thermostat? Seems the most logical to me.

The thermostat was set to 72, you read 66 externally...but what temperature was the thermostat reading?

Thermostat might be broken...

Whitetail said:

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The thermostat was set to 72, you read 66 externally...but what temperature was the thermostat reading?

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Sorry about that. The thermostat was reading 72.

It's a digital Honeywell

Also be cautious using your weber grill thermometer. I am sure it will read a value, but hard to be sure of the value without knowing if it is calibrated.

txag2008 said:

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Don't control to a number, control to your comfort. If you're cold when it shows 72, bump it up to 75.

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This.

I adjust mine up and down for comfort without really looking at the temp.

Whitetail said:

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Also be cautious using your weber grill thermometer. I am sure it will read a value, but hard to be sure of the value without knowing if it is calibrated.

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Yeah, to a grill thermometer, an 8 degree difference isn't a huge fluctuation. Especially if it's not measuring from the same spot on the wall.

Doesn't mean your thermostat isn't going out, but I'd double check with a better thermometer.

Replaced thermostat and everything seems to be working.

Good point on the grill thermometers though. Thanks guys.

DIdnt seem necessary, but sounds like your mind was made up before even posting here.

Higher humidity will require a lower temp to feel comfortable. Dryer air will feel comfortable at a higher temp.

Don't know a lot of details about that particular thermostat, but it could be calibrated incorrectly.

For example, I have a Trane system that come with its own fancy thermostat; well, it gives off heat and the temp directly above the thermostat, which happens to be the temp recorded, is always roughly 3 degrees hotter than ambient. (Checked this with a $20 laser thermometer.) I had to go into settings and adjust the calibration -3 degrees so that the thermostat readout would match ambient temp.

(Alternatively, I could have just set thermostat to my comfort level and ignored the incorrect temp, but it was confusing the wife so in my situation it was better to calibrate.)

Do you have anything that could be giving off heat near the thermostat? Our apartment in college had this issue and then we realized that TV was right under the thermostat, so all of the heat escaping it kept the thermostat reading well above the actual temp.