Water Heater Calculator

A family of 2-3 needs a 40-50 gallon tank or 5-7 GPM tankless. Family of 4-5 needs a 50-80 gallon tank or 7-9 GPM tankless. Base sizing on peak hour demand — the first hour rating should exceed your busiest hour's hot water usage.

Tankless heaters cost 2-3x more upfront but save 20-30% on water heating energy annually and last 20+ years (vs 10-15 for tank). They pay for themselves in 8-12 years. Best for homes with consistent moderate demand rather than extreme peak usage.

Heat pump water heaters are the most energy-efficient (2-3x more efficient than standard electric), saving $200-400/year. Solar water heaters save the most in sunny climates. For gas, tankless condensing units achieve 95%+ efficiency.

Using the Water Heater Calculator is simple: visit the tool page, enter your data or input into the provided fields, and get instant results. No downloads, installations, or sign-ups are required. The tool runs directly in your web browser for maximum convenience.

Yes, the Water Heater Calculator is 100% free to use with no limitations. There is no registration required, no daily usage caps, and no hidden fees. You can use it as many times as you need.

The Water Heater Calculator uses industry-standard formulas and algorithms to deliver reliable results. While the tool is designed for accuracy, results should be used as estimates and guidance. For critical decisions, always consult a qualified professional.

Yes, after running your calculation you can copy the results to your clipboard or take a screenshot. The Water Heater Calculator displays a detailed breakdown so you can easily record or share your numbers. No account is required to use or save results.