E2 Digital Humidistat

I purchased this unit to control a Honeywell whole house humidifier, because it can automatically adjust the humidity level - raising it when the temperature outside rises, and lowering it when it falls. This is essential in order to avoid frost on the windows and mold problems. The humidistat that came with the Honeywell humidifier required manual adjustment, which is too much work to keep doing each time there is a change in temperature.

Now as far as this unit goes - it was relatively easy to install, but should be done by a professional. It is not a drop in replacement for a manual humidistat because it requires two additional wires to be run - one to get 24V AC from the HVAC unit, and the other to a small temperature sensor (provided) which needs to be outside the house. The one caution I have read online on another DIY website is that the wire that goes to the external temperature probe cannot be extended, and the provided wire is only about 30 ft in length...Read more