Solar Water Heating Savings Calculator
Estimate annual backup-energy savings and simple payback for solar water heating from daily hot-water use, temperature rise, solar contribution and energy price.
Default project preview
$417.52
Daily hot-water thermal demand
9.53 kWh
Annual hot-water thermal demand
3,479 kWh
Solar thermal contribution
2,088 kWh
Monthly average savings
$34.79
Calculator
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Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Water-heating energy depends on daily water mass × temperature rise. Solar thermal contribution = annual demand × solar fraction. Avoided backup input = solar contribution ÷ backup efficiency.
FAQ
Solar Water Heating Savings Calculator questions
What is solar fraction?+
It is the share of annual hot-water thermal demand supplied by the solar system rather than the backup heater.
Why can backup efficiency be greater than one?+
A heat-pump water heater may be represented by a coefficient of performance greater than one instead of a resistance or fuel efficiency below one.
Is simple payback a full financial analysis?+
No. It excludes financing, maintenance, incentives, energy-price changes and equipment replacement.