I'm thinking about getting a multi stage or variable speed furnace to go
with my fairly new 10 Seer Carrier condensor. Will the AC air handler fan
speed be set to a fixed speed because the coil could ice up? Will I only
get the benefits of multi speed fan for the heating part? Or maybe, because
of the condensor, have to set it to fixed speed for both functions (and
therefore should get a single speed furnace)? hmmm Just asking so I don't
sound foolish before I talk to the contractors tomorrow.

p.s. I should mention I will be using the Honeywell TH8321U1006 VisionPro
thermostat, the one with sophisticated programming for multi stage systems,
if this makes answer difference for the answer...

On Sep 29, 4:03*am, "scorpionleather" wrote:
p.s. I should mention I will be using the Honeywell TH8321U1006 VisionPro
thermostat, the one with sophisticated programming for multi stage systems,
if this makes answer difference for the answer...

Yes, the multi-stage feature will only work with the heat. Two stage
cooling systems also exist, but you need to replace the outdoor unit
with a two stage one.

JK

You are confusing the two terms. All gas furnaces ( at least all the
major brands) have at least three speed blower motors-- many have four.
This is so the system can be "fine tuned" to get the optimum air flow in
both heating and cooling. Variable speed motors allow even more
adjustment, slowly ramp up to speed, and down on the off cycle. Two
stage furnaces mean that they have two firing rates for the heating --
nothing to do with the cooling side. The fact that you have a 10 SEER
c/u really doesn't change anything. Whichever inside equipment you
choose, it will operate basically the same as though it was all new
matched 13 SEER-- except obviously at less electrical efficiency in
cooling. HTH Larry