Air is invisible. Distribute excessive conditioned air into an unoccupied area, and we hardly even notice. But, if air were water…
Imagine that Mr. and Mrs. Jones live in a 1,500-square-foot ranch home. The one and only water shutoff in the entire house is located in the basement. When Mr. Jones wishes to flush the toilet, he must yell for Mrs. Jones to run down to the basement and turn the water on. When she does, water pours out from the pipes running to showers, sinks, and spigots. (Remember, there are no shutoffs anywhere.) Whenever they need water from one faucet, the whole house gets a soaking. Sounds pretty absurd, doesn’t it? This is precisely what happens to conditioned air in every system that does not have zoning. Energy is being wasted to condition air that is delivered to unoccupied areas.