Question: how much energy required to heat?
Answer: The specific heat represents the amount of energy required to raise 1 kg of substance by 1oC (or 1 K), and can be thought of as the ability to absorb heat. The SI units of specific heats are J/kgK (kJ/kgoC). Water has a large specific heat of 4.19 kJ/kgoC compared to many other fluids and materials.