My Atwood 8525 furnace only has a two wire system, so I can't use this fan fix with my current thermostat.
If you are considering switching to a digital thermostat for fan control, you also might consider a brand that has a low temperature control setpoint.
I chose a
White-Rodgers (an Emerson company) 70 series, programmable, horizontal thermostat because the minimum temperature setpoint was 45F verses 55F for the other digital thermostats available in 2010. Using a lower control point saves both battery and propane when not on electricity. How low you can set the thermostat and avoid freezing will depend on the temperature difference between the living area vs the basement.
The
LuxPro PSD010BF Digital Heat Only Thermostat with Fan Cool mentioned by
rider997 above has a 40F minimumset point.
The Honeywell TH1100DV thermostat mentioned by
MORSNOW has an even lower minimum setpoint of 35F (garage mode), however it does not have the fan control (you need the TH1110DV version for that which has a 40F minimum setpoint).