Water Heating Spreadsheet

Water heating is a major energy consumer. Although the energy consumed daily is often less than for Air Conditioning or Heating, it is required year round, making it a good application of solar energy.

Use this spreadsheet to explore the energy usage of your water heater, and to estimate whether a solar water heater could save you money.

Water Heater Characteristics
Physical		Thermal
Diameter (feet)		Water Inlet Temperature (Degrees F)
Capacity (gallons)		Ambient Temperature (Degrees F)
Surface Area (calculated - sq ft)		Hot Water Temperature (Degrees F)
Effective R-value		Hot Water Usage (Gallons per Day)

Energy Use
		Heat Delivered in Hot Water (BTUH)
		Heat loss through insulation (BTUH)
Gas			Electric
	Overall Efficiency
	Conversion Efficiency		0.98
BTUH	Power Into Water Heater		BTUH
Cost
$/Therm	Utility Rates		$/KwH
$	Yearly Water Heating Cost		$
Solar?
Solar Water Heater Cost: $		Percentage Solar:
years	Payback Time for Solar System		years

This Calculator Supplied courtesy of Chuck Wright Consulting, Technology Serving Sustainability