To air balance you must understand four (4) principles of HVAC

All air balance technicians should know;

  1. To increase temperature, you must add energy, in the form of  heat.
  2. Heat will travel from high temperature to a lower temperature.
  3. It is imposible to cool something.  You only can remove the heat.
  4. Changing the state of a substance (solid, liquid, vapor) requires massive amounts of heat transfer when compared to rasing the temperature of a substance.

The first concept is basic high school physics, has very little to do with air balancing and requires very little discussion. 

To illustrate the second concept think of the times that you have stood outside your front door and opened the door.  Unless your home was perfectly air balanced, in the winter time you have felt a rush of warm air hit you in the face and in the summer time you never felt the cold air from the house hitting you.

The third concept is sometimes hard to get a grasp on and some in the air balance industry think of it as an inegma.  But if you understand concept two that heat can only be transfered or forced from a warmer body to a cooler body with the addition of mechaical energy;  you understand the basic mechanical cooling process.

Concept four requires a definition and an illustration.  All air balancers should understand this concept clearly.  A British Thermal Unit (BTU) is the amount of heat that is required to raise the temperature of one pound of water one degree Fahrenheit.  It takes 760 BTU’s or 760 times the amount of energy, to evaporate (liquid to vapor), one pound of water.  A massive amount of heat transfer.