Estimate sensible heating time, required heater power, or final temperature with material heat capacities, real unit conversion, efficiency, and heat-loss allowance.

Sensible heat only: no melting or boiling. Presets are approximate; use a suitable average specific heat.

Editable; changing the value selects Custom.

Efficiency and extra energy allowance

Default or blank is ideal 100%. This is a delivered fraction, not a heat-pump COP.

Blank means zero. Added as a fraction of useful sensible heat; do not count losses already included in efficiency.

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Heating Time Formula

The ideal formula t = mcฮ”T/P applies when P is net useful heating power. With input heater power, efficiency and the calculatorโ€™s additional energy allowance, use the adjusted model below.

t = m ร— c ร— ฮ”T ร— (1 + L) / (P ร— ฮท)

Variables: ฮท is heater-to-load efficiency as a fraction, and L is additional energy allowance as a fraction of useful sensible heat. Default ฮท = 1 and L = 0 give the ideal estimate. Do not count the same loss in both assumptions.

  • t is the heating time (seconds)
  • m is the mass of the substance being heated (kg)
  • c is the specific heat capacity of the substance (J/kgยฐC)
  • ฮ”T is the temperature change (ยฐC)
  • P is the heater input power (watts)

Multiply mass, suitable average specific heat, and temperature rise to find useful sensible heat. Multiply by (1 + L), then divide by input power times efficiency. The inverse modes use the same allowance: P = mcฮ”T(1 + L)/(tฮท), and Tโ‚‚ = Tโ‚ + Pฮทt/[mc(1 + L)]. This uniform fixed-mass model excludes latent heat, boiling/vaporization, melting and time-varying losses. Material presets are approximate, editable values.

What is Heating Time?

Heating time is the duration required to increase the temperature of a given mass of a substance from one temperature to another when power is applied. This concept is crucial in various fields such as cooking, materials processing, and thermal management in engineering systems. The heating time depends on the mass, specific heat capacity of the material, the temperature change, and the power of the heat source.

How to Calculate Heating Time?

The following steps outline how to calculate the Heating Time.

  1. First, determine the mass of the substance (m) in kilograms.
  2. Next, determine the specific heat capacity of the substance (c) in joules per kilogram per degree Celsius.
  3. Next, determine the desired temperature change (ฮ”T) in degrees Celsius.
  4. Next, determine the power supplied (P) in watts.
  5. Next, use the adjusted formula above, including the selected efficiency and additional energy allowance.
  6. Finally, calculate the Heating Time (t) in seconds.
  7. 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.

mass of the substance (m) = 2 kg

specific heat capacity of the substance (c) = 4186 J/kgยฐC (specific heat of water)

desired temperature change (ฮ”T) = 80 ยฐC

heater input power (P) = 1000 watts, efficiency = 100%, and additional energy allowance = 0%; t = 2 ร— 4186 ร— 80 / 1000 = 669.76 seconds, about 11.1627 minutes