There are three major furnaces types:
- Single Stage Furnace
- Two Stage Furnace
- Three Stage Furnace
For an overview of the pros and cons of furnaces, here is the link .
Not only are the multistage furnaces have a higher efficiency rating but how they are designed to run more efficient which makes even more financial long term sense.
Look at these numbers that are based just on the operating cost of the furnace. These numbers have nothing to do with efficiencies, just purely mechanical operation:
Single Stage Furnace will cost you $1775.15 over five years to operate
Two Stage Furnace will cost you $1235.85 over five years to operate
Modulating Furnace will cost you $775.25 over five years to operate
These are based on 3 Ton Unit and 642 Operating Hours based on .14 Kilowatt/hour
In the first 5 years, the Modulating Furnace will save you almost $1000 in operating costs and lets not forget the extra 5% of efficiencies you'll get from going from a single stage(92% Efficient Furnace) to a modulating furnace(97% Efficient Furnace).
The higher upfront cost of the Modulating Furnace can easily be offset with lower operating costs, higher efficiencies and don't forget about those energy rebates while offering a higher satisfaction in comfort.