Based on this site:
It looks like nest recently added support for multi-speed fan control for some furnaces.
I'm looking to buy a new furnace (mine is old and past its life), but really like using the nest thermostat. It's the first thermostat I've ever used that I actually like. I would like to be able to control as much of the new furnace's features with the nest as possible.
My understanding is that sticking with Nest means I can't use "modulating" or "variable speed" furnaces. However, I think I should be ok with a 2 stage multi speed furnace. 95% efficiency is obviously not as ideal as 98%, but I think I can live with it if it comes with substantial UX benefits.
However, I don't seem (for the life of me) to be able to find any info on what multi-speed furnaces are actually compatible with nest control. In other words, what furnace models use 2 thermostat wires for fan speed control?
Do any of you guys have an info?