Enter the volume of water, the desired temperature rise, and the time over which the temperature rise should occur into the calculator to determine the power required in kilowatts (kW).
KW to Heat Water Formula
The following formula is used to calculate the power required to heat a volume of water by a certain temperature rise over a given time.
P = (V * ΔT * C) / (t * 3600)
Variables:
- P is the power required (kW)
- V is the volume of water (liters)
- ΔT is the temperature rise (°C)
- C is the specific heat capacity of water (4.186 J/g°C)
- t is the time (hours)
To calculate the power required to heat water, multiply the volume of water by the temperature rise and the specific heat capacity of water, then divide by the product of time in seconds (time in hours multiplied by 3600).
| Volume (L) | Temperature Rise (°C) | Time (min) | Power (kW) | Power (W) | Power (MJ/h) |
|---|---|---|---|---|---|
| 1 | 80 | 3 | 1.862 | 1,862 | 6.703 |
| 2 | 80 | 4 | 2.791 | 2,791 | 10.050 |
| 5 | 40 | 5 | 2.791 | 2,791 | 10.050 |
| 10 | 30 | 10 | 2.093 | 2,093 | 7.535 |
| 10 | 20 | 10 | 1.395 | 1,395 | 5.022 |
| 20 | 30 | 15 | 2.791 | 2,791 | 10.050 |
| 30 | 25 | 20 | 2.616 | 2,616 | 9.418 |
| 40 | 20 | 10 | 5.581 | 5,581 | 20.092 |
| 50 | 35 | 30 | 4.070 | 4,070 | 14.652 |
| 50 | 40 | 30 | 4.651 | 4,651 | 16.744 |
| 60 | 30 | 30 | 4.186 | 4,186 | 15.070 |
| 75 | 45 | 45 | 5.233 | 5,233 | 18.839 |
| 80 | 35 | 60 | 3.256 | 3,256 | 11.722 |
| 100 | 30 | 60 | 3.488 | 3,488 | 12.557 |
| 100 | 50 | 60 | 5.814 | 5,814 | 20.930 |
| 120 | 25 | 30 | 6.977 | 6,977 | 25.117 |
| 150 | 40 | 60 | 6.977 | 6,977 | 25.117 |
| 180 | 35 | 90 | 4.884 | 4,884 | 17.582 |
| 200 | 30 | 60 | 6.977 | 6,977 | 25.117 |
| 300 | 50 | 180 | 5.814 | 5,814 | 20.930 |
| * Rounded to 3 decimals (W rounded to nearest unit). Assumes water density 1 kg/L and specific heat c = 4.186 kJ/kg·°C. Formula: P(kW) = V(L) × ΔT(°C) × 4.186 ÷ time(s). Unit links: 1 kW = 1000 W, 1 kW = 3.6 MJ/h. | |||||
What is KW to Heat Water?
KW to heat water is a measure of the energy rate required to raise the temperature of a given volume of water by a certain degree over a specified period. It is an important calculation in designing heating systems, such as water heaters and boilers, to ensure they have sufficient power to meet the heating demands.
How to Calculate KW to Heat Water?
The following steps outline how to calculate the power required to heat water.
- First, determine the volume of water to be heated (V) in liters.
- Next, determine the desired temperature rise (ΔT) in degrees Celsius.
- Next, determine the time over which the temperature rise should occur (t) in hours.
- Next, gather the formula from above = P = (V * ΔT * C) / (t * 3600).
- Finally, calculate the power required (P) in kilowatts.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Volume of water (V) = 100 liters
Temperature rise (ΔT) = 30°C
Time (t) = 2 hours
