Sensible & Latent Heat Calculator
Enter mass, material and temperature change to get sensible heat in kJ/kWh/BTU — with the freeze and boil latent heats of water shown for comparison.
Last updated: 2026-09-28
How the calculation works
- Sensible heat is mass × specific heat × temperature change — the energy that moves the thermometer.
- For water, the latent rows show the energy of phase change: 334 kJ/kg to freeze, 2257 to boil.
- kWh and BTU conversions make the figure comparable with energy bills and equipment ratings.
Formula
Q = m · c · ΔT (sensible, no phase change)
| Symbol | Meaning | Unit |
|---|---|---|
Q | Heat added or removed | kJ |
c | Specific heat capacity | kJ/kg·K |
Worked example
Interpreting the result
Sensible heat moves the thermometer; latent heat moves the phase. Water's numbers explain most of HVAC: air conditioning spends much of its energy condensing moisture (latent), not cooling air (sensible) — and a kWh is 3600 kJ, so the tank above stores what a 2 kW element delivers in 4.4 hours. Thermal mass (concrete, water) buffers temperature swings because of its high c × density product.
Assumptions
- Specific heats at room temperature; c varies mildly with temperature.
- No phase change within the entered temperature span (sensible only).
Limitations
- Latent heats shown only for water at 1 atm (334/2257 kJ/kg).
- Mixtures and moist air need psychrometric treatment, not a single c.
Frequently asked questions
What is the difference between sensible and latent heat?
Sensible heat changes temperature (you can feel it with a thermometer); latent heat changes phase at constant temperature — melting ice or condensing steam. Water's latent heats are 80× and 540× the energy of heating it 1 °C.
How many kWh to heat a water tank?
kWh = litres × ΔT ÷ 860 roughly (water). A 150 L tank over 50 °C: ~8.7 kWh — multiply by your rate for the cost per heat-up.