I am seriously considering a TempStar VS-95 (variable speed fan, 95% efficiency) to replace my 20 year old Carrier, and to qualify for federal and state tax credits. Can I keep my programmable one stage thermostat or should I get a new one? If so, which would be a good fit? The people I am talking to seem to think that using my current thermostat would be fine (thus yielding a time based decision for going from stage 1 to stage 2) by setting a dip switch on the furnace board. This is for a moderate climate (Portland, Oregon). Would a multi-stage thermostat be better? (Why?) Which one would you recommend? (Honeywell Vision Pro 8000 ? - specific model?) Thanks.