热水器能效计算器
使用热水器能效计算器评估不同类型热水器的运行效率和成本。比较燃气、电热和热泵热水器的能效系数和年度能耗，选择最节能经济的热水方案。
Annual Water Heating Cost
436 USD
Annual Water Heating Cost vs Daily Hot Water Usage
公式
How to Calculate Water Heater Costs
Water heating is typically the second largest energy expense in a home (14-18% of energy bills).
Formula
Daily BTU = Gallons * Temp Rise * 8.33
Annual Energy = Daily BTU * 365 / Energy Factor
Energy Factors
计算示例
50 gal/day hot water, 60F temp rise, 0.92 energy factor, $0.15/kWh.
- 01Daily BTU: 50 * 60 * 8.33 = 24,990 BTU
- 02Daily energy with EF: 24,990 / 0.92 = 27,163 BTU
- 03Annual energy: 27,163 * 365 = 9,914,526 BTU
- 04Annual cost: 9,914,526 / 3,412 * $0.15 = $436
常见问题
What is the most efficient water heater?
Heat pump water heaters are the most efficient, with energy factors of 2.0-4.0, meaning they use 2-4x less energy than electric resistance heaters. They cost $1,200-2,500 installed.
What temperature should my water heater be set to?
The recommended setting is 120F, balancing safety and efficiency. Every 10F reduction saves 3-5% in water heating costs.
How much of my energy bill is water heating?
Water heating accounts for about 14-18% of the average home energy bill, or $400-600 per year. This makes it the second largest energy expense after HVAC.