1 stage or 2 t-stat w/variable speed furnace?


Old 12-16-08, 05:31 PM
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1 stage or 2 t-stat w/variable speed furnace?

I'm getting quotes on a new furnace. 2 are Trane TUD080R9V3 80K variable speed to go w/ my 1 yr. old Trane AC. One company wants to change out my White-Rodgers IF80-261 single stage programmable thermostat w/ the White-Rodgers 2 stage IF81-261. I live in Atlanta, GA. Is the 2 stage thermostat worth the extra $125? My understanding is that the furnace will still be variable speed but the low-to high speed change will occur by a time set rather than a temp setting. All advice welcome. Thanks.
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Old 12-16-08, 05:56 PM
Join Date: Mar 2006
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Variable speed refers to the blower. If this furnace has two stages it has a low and high firing rate. A two-stage furnace really works best with a two-stage thermostat. The alternative is a timed delay before the high output stage fires.

I have a two-stage Lennox, the smallest model they sell in a counterflow model and the first (low) stage works just fine for me. Currently we are experiencing record low temperatures and the furnace is keeping my home quite comfortable cycling on the low stage only.
Old 12-16-08, 09:34 PM
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Get a two stage t-stat.. You get better comfort with a two stage t-stat.

I am not a brand basher, but I am not a fan of t-stat that "Swings" for temps.

Honeywell give you the best comfort, and better run time. I would suggest the Honeywell FocusPro, or VisionPro t-stat.

Our temps been down around -10˚, and the furnace has been running steady in 1st stage and giving us the best comfort all over the house. When we see -20˚, then our 2nd stage will be running more.
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