Water Heater Calculator
Calculate water heater sizing for tank and tankless systems. Compare gas tank, electric tank, tankless gas, tankless electric, heat pump, and solar water heaters. Includes annual operating costs and 10-year total cost of ownership analysis.
| Tank (Selected) | Tankless | |
|---|---|---|
| Upfront Cost | $2,200 | $2,700 |
| Annual Operating | $407 | $250 |
| Expected Lifespan | 10 yrs | 20 yrs |
| Lifetime Cost | $6,271 | $7,693 |
| Fuel | Cost/Unit | Tank Eff. | Tankless Eff. | Notes |
|---|---|---|---|---|
| Electric | $0.12/kWh | 92% | 99% | Widespread, easy install, higher operating cost |
| Natural GasSelected | $1.2/therm | 67% | 95% | Most common, lower operating cost |
| Propane (LP) | $2.5/gallon | 60% | 90% | Rural areas, requires tank |
| Heat Pump (Hybrid) | $0.12/kWh | 92% | 99% | 2-3x more efficient than standard electric |
How to Use Water Heater Calculator
- 1Enter household size and usage level
- 2Select current heater type
- 3Compare 6 water heater types
- 4View sizing and 10-year cost of ownership
Frequently Asked Questions
What size water heater do I need?▾
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.
Is tankless worth the extra cost?▾
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.
What is the most efficient water heater?▾
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.
About Water Heater Calculator
Calculate water heater sizing for tank and tankless systems. Compare gas tank, electric tank, tankless gas, tankless electric, heat pump, and solar water heaters. Includes annual operating costs and 10-year total cost of ownership analysis.
NexTool's Water Heater Calculator is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.
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