Hey Ed, is there a difference between a block load and a room-by-room load?

In this edition of “Hey Ed,” Ed discusses the difference between a block load and a room-by-room load.

Hey Ed, is there a difference between a block load and a room by room load? There’s absolutely a difference between those two. When we are trying to calculate how much heating or cooling we need for an existing home, I am typically going to perform a block load. If I am trying to determine how many BTUs are required for individual rooms via baseboard heat or a forced air system, that is where a room by room load is required. When we get to the equipment selection part of a system design, Manual J will give us a block load and that is what’s used for us to follow the guidance in Manual S. And that’s the way I see it.