On an energized, intact circuit, you will read voltage across an OPEN switch when testing with a voltmeter. However, you probably won't read significant voltage across a CLOSED switch. Both sides of a closed switch are electrically identical (or at least very close). Therefore, there should be no movement of electrons between the leads of […]

Air changes per hour (ACH/ACPH) simply describes how many times the quantity of air in a room (or structure) is completely replaced per hour. If you have a 10'x10'x10′ room, the room contains 1000 cubic feet of air. If the supply and return to the room is supplying a balanced 100 CFM (cubic feet per […]

A friend of mine was telling me that a utility had the idea that they could reduce energy consumption by turning HVAC equipment on and off rapidly during times of high load. In their minds, wouldn't it be better to spread out the off time rather than keeping the system off for longer periods and […]