Heating and Cooling Equipment Legacy System

The Home Energy Saver web site models the following heating and cooling equipment types:

*Default Efficiency is AFUE unless otherwise indicated. See the Equipment Efficiencies Page for information on how efficiencies are calculated from year purchased.

** Capacity for this equipment type is automatically calculated in the DOE-2.1 model.

*** Usage for this equipment type is calculated in the DOE-2.1 model, based on user-specified thermostat settings and schedule (see below)

DOE-2.1 models both electricity and other fuel usage for equipment types with multiple fuels (e.g. Central Gas Furnaces, which use natural gas for heating and electricity use by the air-handler fan). Air-handler fan efficacy is assumed to be 0.5 watts/cfm for standard equipment with PSC motors and 0.375 watts/cfm for equipment with ECM motors (ECM motors are assumed in these cases: SEER > 13.5, HSPF > 8.5, or AFUE > 90%).

For those equipment types modeled in DOE-2, the equipment characteristics are input to the DOE-2 model. Energy consumption in million BTUs is returned from DOE-2 and converted to the units in which the consumer would purchase the fuel, using the fuel-specific conversion factors found in the table below