You may be getting confused by all the options out there. Who would have thought buying a heating system would have as many options as going to the car dealer! As technology advances so do your options. There are many factors that need to be considered:
If you are looking for something that does it all and has the combined features of a dual stage or two stage furnace as well as the features of the variable speed, then here is the option for you. These furnaces are the full package. Meaning that the furnace fan can run on low and high speed as needed and the gas valve in the furnace can change from low fire to high fire depending on the heating need of the home. An energy efficient furnace that is also very quiet!
There is yet another option to the already good combination of the dual stage furnaces and variable speed fan furnaces and that is the modulating variable speed fan furnace. The modulating part means that instead of a two stage gas valve there is a gas valve in the furnace that can vary even more as the thermostat tells your heating equipment what to do which can save you even more money by being able to work in between low fire and high fire rather than just switching from low fire to maintain up to high fire to heat. It can meet anywhere in the middle and ramp your furnace up and down as necessary to keep you home comfortable and warm while working for your best interest at the same time.
The RUUD RGFG - Series. The RGFG series is a 95% efficient modulating gas furnace. This modulating furnace is equipped with RUUD's comfort control 2 system and the following features: