I have a story and a half with separate units for the upstairs and down. I have a regular digital thermostat upstairs and a fancier Honeywell with Wifi on the main floor. Both set to the same temperature.

I never gave it much thought, but when coming downstairs from above you could always feel that it was a bit cooler. Heat goes up, and the fact that it is a story and a half may get a bit more radiant heat from the roof.

The other day I got my monthly energy usage report from Honeywell. It compares this year to last. Average high and low temperatures for the entire month were roughly the same, except this year the A/C ran for 124 hours more than last year. That's a little over 4 hours a day, each and every day.

Then I begin to wonder. If it's cooler downstairs than up, and both are set to the same temperature, then perhaps one of the thermostats is wrong. I set up two separate digital thermometers on the wall right next to each thermostat. Upstairs is correct. All three show the exact same humidity and temperature.

The fancy wifi thermostat downstairs shows a different humidity and temperature than the two independents which both match. As of my typing this the thermostat is showing 4% less humidity and 3 degrees higher temperature.

I'm assuming these can't be calibrated and that I should just replace it?

Think metric. It's less than 1.7 degrees different. Not a big deal.

Why calibrate it? Just set it three degrees higher and see if your thermometer matches what you want.

There are a myriad of settings available in a hidden menu. You should have info on it in your owners manual if available.

ETA

Just checked my older one has that ability 8000 series (TH8320WF1029). It's 0700 on system setup menu. Can adjust +/- three degrees.

This message has been edited. Last edited by: Skins2881,

There is a 'temperature offset' setting in the setup menu.

What's the model number?

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What's the model number?

RTH9580WF1005

quote:

Just set it three degrees higher and see if your thermometer matches what you want.

I did, and it did. The deviation is something fairly recent as it has worked accurately in the past.

quote:

Just checked my older one has that ability 8000 series (TH8320WF1029). It's 0700 on system setup menu. Can adjust +/- three degrees.

I haven't messed with it at all, but appreciate the info. I'll dig into it and see what can be adjusted. For all I know one of the kids messed with it and caused its current issue via adjusting it.

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Originally posted by a1abdj:

RTH9580WF1005

Here you go... directions to change temp offset.
https://tomstek.us/calibrate-h...mperature-rth9580wf/

Thank you.