VisionPro IAQ

[Steven]

Hi, What is the difference between these two versions of the Honeywell VisionPro IAQ thermostats? YTH9421C1002 & YTH9421C1004

[.p.jm.]

The last digit.

[zero]

Hmm... this might be a trick question being he's asking about the difference between the two.

My guess is a difference of two units. :o)

-zero

[.p.jm.]

Oh.

Nevermind.

[Steven]

[Steve]

I can only find info on the 02 with a cursary search... What are you doing with it?? What are you needing it to do?? what type of system?? what accessories?? etc........ There may be something else that Honeywell makes that will do what you need it to.

[Tony Hwang]

Hi, Of my head, possible difference is number of stages in heating/colling cycle, gas or electric, etc.