Calculating the heat energy being absorbed or released in a system may be accomplished by using the following formula:

Heat gained or lost = Mass x Change in Temperature x Specific Heat

Mass is the mass of the matter being measured.  Change in temperature is the increase or decrease in the temperature of the matter measured in Celsius and Specific Heat is the specific heat value of the substance (for air for example it's 0.25).  Specific heat is defined as the amount of heat energy required to raise 1 g of a substance by 1° Celsius.  This value is different for various types of matter.