Stiebel Eltron Vs "Conventional" Storage Tank Water Heaters
This data is based on a family of four.

To see data based on a family of two, click here.

The following comparison is based on a family of 4.
Assuming 4 daily showers, 2 hand washing applications per person, 1 hand dishwashing based on filling the sink and 4 bathroom sink usages per day. Total of 93 gallons of hot water used per day.

  Stiebel Eltron GE Electric (40 gal) GE Electric (40 gal) GE Natural Gas (40 gal) GE Natural Gas (40 gal)
Model Tempra 20 GE 40T6A PE 40M9A SE 40M12A GG 40T6A PG 40T9A SG 40T12A
Energy Factor 0.98 0.88* 0.91* 0.93* 0.57* 0.56* 0.62*
Cost $/year 273 505** 489** 478** 395** 402** 363**
Savings $/Year   232 216 205 122 129 110
% Savings   46 44 43 31 32 30
  Stiebel Eltron GE Electric (40 gal) GE Electric (40 gal) GE Natural Gas (40 gal) GE Natural Gas (40 gal)
Model Tempra 20 GE 50T6A PE 50M9A SE 50M12A GG 50T6A PG 50T9A SG 50T12A
Energy Factor 0.98 0.86* 0.91* 0.93* 0.56* 0.54* 0.62*
Cost $/year 273 517** 489** 478** 402** 417** 363**
Savings $/Year   244 216 205 129 144 110
% Savings   47 44 43 32 35 30

*These Energy Factors are present in new appliances, a conventional electric tank will perform at 80% efficiency after the first year and degrade slowly thereafter. The Stiebel Eltron Tankless Water Heater is rated an incredible 99%+ efficient for the lifetime of the heater!
**ADD $150-$200 /year if you rent your tank.


Assumptions:
$0.0719 per kWh for electricity is the SW Ontario average electricity supply rate.
$0.38/cubic metre for gas is the regulated Consumers Gas natural gas supply rate (Jan 2001), included is a $10.00 per month service charge.

Hot Water Usage Estimates:
Average shower (10 minutes) - 20 gallons
Average clothes washer (one load) -- 10 gallons
Average dish washer (one load) -- 6 gallons
Average faucet flow -- 2 gallons/minute
Total average daily usage is 64 gallons per day
Usage Assumption:

Tank Temperature setpoint of 135° F, inlet water temperature of 55° F and 365 day a year use.
These comparisons are based on the U.S. Department of Energy Hot Water Usage Guidelines as reported on the Energy Efficiency and Renewable Energy Clearing-House.

Energy Factor and Average Annual Operating Costs based on D.O.E. (Department of Energy) test procedures.
http://www.eren.doe.gov/femp/procurement/calc_waterhtr.shtml