Heat Transfer Calculator
Calculate heat energy needed to change an object's temperature (Q = mcΔT).
Results
The heat transfer equation Q = mcΔT calculates the energy needed to change an object's temperature. It is fundamental in HVAC design, cooking science, industrial processes and climate science. Water has an exceptionally high specific heat (4186 J/kg·°C), which is why it is used as a coolant and why oceans moderate climate.
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Frequently asked questions
Q = 1 × 4186 × 80 = 334,880 joules or about 335 kJ. That is roughly 0.093 kWh, which costs about 1 cent at average electricity rates.
Water's specific heat (4186 J/kg·°C) is about 10 times higher than iron (449 J/kg·°C). Heating 1 kg of water by 1°C requires 4186 J, while iron only needs 449 J.
A 50,000 L pool weighs 50,000 kg. Heating from 15°C to 28°C (ΔT = 13°C): Q = 50000 × 4186 × 13 = 2.72 billion J = 755 kWh, costing about $90 at $0.12/kWh.
Specific heat is the energy per kg per degree. Materials with high specific heat (water: 4186) change temperature slowly. Low specific heat materials (copper: 385) heat up quickly - that is why copper pans heat fast.
1 kcal = 4184 J, 1 kWh = 3,600,000 J, 1 BTU = 1055 J. To heat 1 kg of water by 1°C takes 1 kcal (by definition), which is 4.184 kJ or 0.00116 kWh.