Most of you reading this column consider yourselves heating professionals. As such, you deal with units such as Btuh, kW, therms, and tons on a daily basis. For the most part, you use valid units to describe physical quantities. For example, you know that flow rate is measured in gallons per minute (gpm) and not gallons. You also know that temperature is expressed in °F or °C, and not in therms.
But, when it comes to the difference between energy and power, our industry tends to get sloppy with its terminology. For example, we might tell a potential customer how a new geothermal heat pump could reduce his power bill. We also might describe the choice between a couple of boilers as the 75,000-Btu model versus a 100,000-Btu model.