US energy regulators will now measure air conditioners for off-mode power use

The US Department of Energy has updated its testing rules for central air conditioners and heat pumps. Manufacturers will now have to measure how much power these units use when they are turned off, in addition to how much power they use when running.

For decades, energy efficiency standards focused on how much power appliances used when they were on. This meant manufacturers had little incentive to reduce the power used when the appliance was off, even though many appliances spend most of their time in standby mode. This change means manufacturers will now have to design for efficiency across the entire operating cycle, not just when the unit is actively cooling or heating.