Many RVs feature old style thermostats where the temperature needs to be controlled manually. Also, in most cases, older thermostats only control the furnace while the A/C controls are on the outside of the unit. Today’s newer thermostat models can control both the furnace and the air conditioner. These reasons alone are why many RV owners are opting to do an RV thermostat replacement to one that is digital, programmable and can regulate both heat and air.