water temperature card savings calculations

These calculations display your estimated savings based on assumptions below

For customized calculations enter your own data in the green fields

surface area of water heater sq ft
temp of hot water °F
water heater surrounding temperature °F
water heater R value
water heater efficiency %
type of water heater

cost per kilowatt hour
cost per therm
cost per CCF
cost per cubic meter
1 CCF = 103,100 BTU = 1.031 therm
1 m3 = 35.31 ft3 = 0.3531 CCF

How your savings are calculated

Step 1 determine heat loss at current temperature

37.5 sq ft x (140 hot temp - 70 ambient air temp) / (16 water heater R-value + 0.6 air film R-value) = 158.13 BTU/hr

Step 2 determine heat loss at new temperature

37.5 sq ft x (120 new hot temp - 70 ambient air temp) / (16 water heater R-value + 0.6 air film R-value) = 112.95 BTU/hr

Step 3 determine heat loss savings

158.13 current heat loss - 112.95 new heat loss = 45.18 BTU/hr heat loss savings

45.18 BTU/hr / 85% = 53.15 efficiency-adjusted savings

Step 4 convert to kW

53.15 BTU/hr / 3,412 BTU/kWh = 0.0156 kW

Step 5 determine energy savings

0.0156 kW x 24 hrs/day = 0.3744 daily kWh

0.3744 kWh/day x 365 days/year = 136.656 yearly kWh

136.656 kWh/year x 15 year lifespan = 2049.84 lifetime kWh

Step 6 determine money savings

136.656 yearly kWh x $0.118 = $16.13 yearly savings

2049.84 lifetime kWh x $0.118 = $241.88 lifetime savings

Savings calculations are presented as an example of potential savings; actual savings may vary based on use, utility rates and other factors. Calculations are based on national averages and assumptions and may be adjusted for a more accurate estimate of individual savings. While EnergyEarth strives to provide the most accurate information, we cannot guarantee the savings displayed.