Watts to Heat Calculator

Watts to Heat

Convert electrical power to thermal energy units like BTU and kcal.

Heat Output (Power Rate)
3412.14
BTU/hr
Total BTU
3412.14
Rate (kcal/hr)
859.85
Total energy: 859.85 kcal

Heat and Power

In many applications, electrical power is converted directly into heat. For example, an electric space heater converts 100% of its electrical input into thermal energy.

A British Thermal Unit (BTU) is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. A kilocalorie (kcal) is the amount of heat required to raise the temperature of one kilogram of water by one degree Celsius.

Conversion Factors & Formulas

Power Rate (instantaneous energy flow per unit time)

1 W = 3.412142 BTU/hr

Heat output rate in British Thermal Units per hour

1 W = 0.859845 kcal/hr

Heat output rate in kilocalories per hour

Total Energy (cumulative over time period)

Total BTU = (Power in W × 3.412142) × Time (hours)
Total kcal = (Power in W × 0.859845) × Time (hours)

Multiply the rate by duration to get total energy consumed in that time period. Example: 1000 W for 24 hours = 81,573 BTU or 20,636 kcal of heat.

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