Furnaces
Standard Efficiency
These are for a home that needs to replace their existing 80% two stage gas furnace or single stage condensing gas furnace.
Multi-stage or communicating
Two stage gas furnace and modulating furnaces for the most part need matched systems and thermostats. The benefit is increased control and efficiency. Downside is that updating duct work or wiring may lead to additional costs.
2 Stage= Comfort
Two stage gas furnaces are designed to run longer at a reduced energy consumption resulting in increased comfort.
Condensing= Savings
AFUE ratings simply tell you the amount of each dollar you are utilizing. The higher the AFUE the more you are saving. It does however come at a cost. Matched systems and thermostats become mandatory the more efficient a machine becomes.