I have a 93% efficient furnace and 14 seer AC unit. Everyting seems to work fine but my furnace only runs 3-5 minutes at a time it does maintain the 70 degrees set on the furnace no problem. I have a Honeywell Chronotherm 111 thermostat. I was told it really causes the furnace to cycle to frequently. Any suggestions on a Tstat for this. It appears White Rogers Tstats will let you adjust temperature variance which will let the furnace burn longer. It seems to me the furnace is not near as efficent when it only burns 3-5 minutes. Just when the ductwork etc is warmed up it shuts down. Maybe I am wrong. Your thoughts will be greatly appreciated.