# Heater won't keep up in extreme cold, A/C won't keep up in extreme heat!



## JoJoRabbit (Dec 20, 2021)

I have an all-electric carrier central heat/air conditioner about 12 years old and a Honeywell wifi smart thermostat about 3 years old. My central unit struggles on hot summer afternoons and cold winter nights and in both cases doesn't cool to the set temperature or heat to the set temperature. On hot summer days it's set to 79 but the temp rises to the mid-80's inside if it's above 96 outside. In the winter it's set to 73 but it won't go above 69 - but only if the temp outside is below 39.
I hired 2 companies to diagnose the problem, and both thoroughly checked the outside system and the parts in the attic and both companies said the system is running as it's supposed to, they can't find anything wrong with it. It is sized appropriately for the home. They don't know why it struggles in extreme temperatures. 
One of the technicians said my attic is very hot when he checked it in the summer, but I don't know if that would have anything to do with extreme cold causing the heater not to keep up in the winter.
Does anyone have any ideas why this is happening or what else can be examined?


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## beenthere (May 30, 2009)

Sorry, we're a tradesmen only site.

Please use our sister site DIYCHATROOM.COM, thank you.

Thread closed.


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