NEST thermostat question

[dcj2045]

Hello there,
I have a technical question about the new nest t-stat. I have a Honeywell steam humidifier and I would like to buy the new nest thermostat, I was wondering how to wire the humidifier to the new nest t-stat? and I would like to humidified the house even if the heat is not on, also want the humidifier to come on only if the fan is on; Can you please help. I have a PDF file link to my humidifier and to the nest wiring Thank you in advance.
NB : (OPTION 4: VisionPRO IAQ without Fan Delay) is the way my furnace is wired.

http://www.nest.com/blog/2012/10/02/the-next-generation-nest-thermostat/

http://www.forwardthinking.honeywell.com/related_links/humidification/69_2285.pdf

[54regcab]

The nest is a "dumb thermostat" as far as connectivity and options are concerned. Single stage or Heat pump is all it can do. For a about the same more money you can get an ecobee with the humidity control built in. It has multiple configuration options built in. The ecobee is NOT a DIY install for most people, professional installation recommended.

[jpsmith1cm]

dcj2045

I started a new thread for you.

[54regcab]

Here's a quote from the ecobee installation manual (http://ecomfort.com/PDF_files/Ecobee/ecobee_EB-STAT-02_installation_manual.pdf)

Humidifier: Select this option when the Thermostat
is required to control a humidifier. When this option is
selected you will also be able to configure the following:

Humidify only while heating If Yes is chosen, the
system will activate this relay when the current
humidity is below the humidity set point and there
is a call for heat.

If No is chosen the system will activate this relay and
the system fan when the current humidity is below
the humidity set point. This is designed to support
steam type humidifiers.

Nest has absolutely no humidifier control at all, much less an option of how it's controlled. The only advantage Nest has over ecobee is it's pretty.

[54regcab]

I totally missed that you already have a Honeywell IAQ, why would you want to downgrade to a Nest?

[mark beiser]

I wasn't aware that it was out yet, but it appears the 2nd generation Nest thermostat is able to control a humidifier.
It only does a 1 wire connection for humidity control, so a relay will need to be added to operate the humidifier.

With the Nest, you still can't have both humidifier control and dehumidification control like your IAQ thermostat.