Smart Thermostat vs Humidistat for Whole-Home Humidifier


Old 09-12-19, 01:16 PM
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Smart Thermostat vs Humidistat for Whole-Home Humidifier

I'm seeking help in several different communities for advice, as I'm conflicted and confused... thanks for your help and patience!

I recently moved into a new home with a Honeywell whole-home evaporative humidifier added on to the HVAC system. I'm excited to use it once winter sets in, as I've previously needed to run single room humidifiers in previous rented apartments and townhomes to avoid drying out. This system is currently turned off while the humidity remains high for the summer in southern Wisconsin. It is connected to a humidistat that is mounted to the return duct with a probe to measure the average humidity from the entire home. I currently have an ecobee SmartThermostat with Voice Control managing the HVAC system. I did not hook up the humidifier to the ecobee.

I recently had HVAC maintenance done in anticipation of winter, and the contractor that came out helped me discover that I had a free thermostat wire that I could use to hook up the humidifier to the ecobee. However, he advised against doing so, reasoning that the return duct would do a much better job getting the average humidity in the home and operating the humidifier. He didn't seem to know much about smart thermostats and was hostile to Nest in particular, so I'm not sure I was getting fully unbiased advice and am looking for second opinions. I like the idea of being able to manage the humidity levels without having to fiddle with the humidistat, monitor the usage and performance of the humidifier, and reap the benefits of comparing outdoor and indoor data to help drive how the humidifier operates. The thermostat is centrally located on the main floor of the home, so I'm not sure its humidity readings would be much different than the humidistat's readings on the return, negating the benefit that seemed to drive the original recommendation I received.

Any help or advice is much appreciated!
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Old 09-12-19, 01:28 PM
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Welcome to the forums.

A humidistat in the living area is actually a better idea. We usually just mount then to the return duct as that is easier and does work. I have mine on the return duct. I adjust my humidity level almost daily or every other day. I adjust it based on the outside temperature, how it feels inside and the biggie is condensation on the windows. Condensation on the windows and their frames should be avoided.

To get to your question..... yes.... the Ecobee can control the humidifier for you. You could certainly try it and see if it repsonds to your satisfaction.

Typically only one wire is needed for the Ecobee to control the humidifier. I'd need the model number of your humidifier to comment further.
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Old 09-14-19, 01:26 PM
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Thanks so much, Pjmax! This is very helpful information. The humidifier is a Honeywell HE250, and the humidistat is a Honeywell HumidiPRO. I checked, and it is accurately pulling in the outdoor temperature. It appears the original installer wired the remote sensors.

Knowing that and what you might know about the model number, do you have any other thoughts?
Old 10-06-19, 07:23 AM
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Pjmax, can you provide more insight?

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