Equipment Type

Relative
Performance¹

    1998
Installed Cost
($1998)²

Efficiency³

      2015
Installed Cost
($1998)²

 Efficiency³

Approximate
Discount
Rate

Electric Heat Pump    

Minimum
Best

$4,100
$5,555

10.0
17.7

$4,100
$5,200

10.0
18.0

38%

Natural Gas Furnace    

Minimum
Best

$1,300
$2,700

0.78
0.96

$1,300
$1,600

0.78
0.96

15%

Room Air Conditioner    

Minimum
Best

$450
$760

8.7
11.7

$450
$760

9.7
12.0

140%

Central Air Conditioner    

Minimum
Best

$2,500    
$3,600    

10.0
18.0

$2,500 
$3,200

10.0
18.0

 36%

Refrigerator (18 cubic ft)    

Minimum
Best

$530
$850

690
518

$530
$700

478
400

19%

Electric Water Heater    

Minimum    
Best

$350
$1,025    

0.86
2.60

$350
$800

0.86
2.20

83%

Solar Water Heater

N/A

$2,600

2.0

$2,600

2.0

83%

¹Minimum performance refers to the lowest efficiency equipment available.  Best refers to the highest efficiency equipment available.
²Installed costs are given in 1998 dollars.
³Efficiency measurements vary by equipment type.  Electric heat pumps and central air conditioners are rated for cooling performance using the Seasonal Energy Efficiency Ratio (SEER); natural gas furnaces are based on Annual Fuel Utilization Efficiency; room air conditioners are based on Energy Efficiency Ratio (EER); refrigerators are based on kilowatt-hours per year; and water heaters are based on Energy Factor (delivered Btu divided by input Btu).
Source:  Arthur D. Little, EIA Technology Forecast Updates, Reference Number 37125, September 1998.