I installed a Goodman GMVC95 natural gas furnace and a Honeywell RTH7400 thermostat. When I fired the furnace up, the blower didn't seem to be blowing at full capacity and th house was heating very slowly. The furnance was set for a two stage thermostat so I switched the dip switch for single stage stat and the blower seems to be going better now. So, it would seem the Honeywell is a single stage thermostat. I can't find anything in the documentation or on the package that says either way.

Would I benefit from replacing the thermostat with a two stage thermostat and resetting the furnace?

Greg