My upstairs aircondition is set to 78 and the downstairs is set to 76 which I believe is correct. Issue is that upstairs seems much colder then 78 although the temp on the unit indicates otherwise. So my question is first, are the two degrees the appropriate settings and second, if it does seem colder upstairs (seems counter intuitive as the cold air should generally have more mass) what can I do to verify things are working correctly?

Thanks,
Mariob

I think I would check it with another thermometer. Our last house had a dual system and I set the upstairs at what fel comfortable. Same with the downstairs. I didn't pay attention to the variation as maybe I should have. But if the upstairs feels cool, raise the temp. We had and still use ceiling fans continually. It keeps the air circulated and I think it makes it easier on the AC unit.

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Originally Posted by westnlas

I think I would check it with another thermometer. Our last house had a dual system and I set the upstairs at what fel comfortable. Same with the downstairs. I didn't pay attention to the variation as maybe I should have. But if the upstairs feels cool, raise the temp. We had and still use ceiling fans continually. It keeps the air circulated and I think it makes it easier on the AC unit.

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Good answer. Most thermostat thermometers are + or - a lot (7% for bi-metallic). Another consideration is "where are the thermostats mounted in the return air path, back to the evaporators?" Perhaps they are not "sensing" where you feel the colder draft... In many applications, stairwells and corridors are used as "return air ducts" to the air handlers. A closed door interrupts this flow, and unbalanced registers also contribute to the problem.

Ceiling fans do make it easier on the HVAC system :)