Heating and Cooling Equipment Legacy System

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


 

Equipment Type

 

Calculation

Default Efficiency*
Default Capacity

Default

Usage

Heating

Central Gas furnace

DOE-2

78

**

***

Room (through-the-wall) Gas furnace

DOE-2

65.6

**

***

Propane (LPG) furnace

DOE-2

78

**

***

Oil furnace

DOE-2

80

**

***

Electric furnace

DOE-2

98

**

***

Electric heat pump (heating)

DOE-2

7.0 HSPF

**

***

Electric baseboard heater

DOE-2

98

**

***

Gas boiler

DOE-2

80

**

***

Oil boiler

DOE-2

80

**

***

Cooling

Central air conditioner

DOE-2

9.5 SEER

**

***

Room air conditioner


9.0 EER

13,000 Btu/hr

Hrs/day=5,

Days=99

Electric heat pump (cooling)

DOE-2

9.5 SEER

**

***

Whole house fan


powerfan=0.3 kWh; hours/day=2; months=2

Ceiling fan


Numberfans=2

Portable fan


Numberfans=2

*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


Fuel

Conversion factor

(site energy)

Electricity

3412.76 BTU/kWh

Natural Gas

100,000 BTU/therm

Liquid Propane

91,500 BTU/gallon

Fuel Oil

138,690 BTU/gallon