Just grabbed 2 Honeywell whole house humidifiers: HE360A1075. It's the best model Lowes has and recommends.
I have 3 floors and a basement in an old (1890s) victorian house. We have cast iron radiators with a gas boiler for heat on the bottom 2 floors (original) and separate ducting for the AC; then a regular AC/gas furnace ducting for the top 2 floors.
For the top two floors the install should be easy, I assume, as we have water and drain locations up there.
For the lower floors, can I install the humidifier in the AC ducting and have the thermostat power just the blower, and not actually turn on the AC?
I have 2 Nest gen 2 thermostats, which I believe can control the humidifiers too.
So - key question:
Can I install the humidifer on the AC ducting and use the AC blower, without turning on the AC? This should be controlled by the Nest to turn on whenever humidy is low.
Note - there is no heating furnace, just an AC unit.