You may be wondering what the difference is between wattage (also called running or ranked wattage) and surge wattage (also referred to as start-up wattage). Running wattage indicates that the electricity a motor-driven appliance uses once it reaches normal operating speed. Surge wattage represents the power the appliance consumes as its motor begins and gets up to two-thirds of its operating speed.
Depending on the operating efficiency and the power factor of the air conditioner’s hermetic motor-compressor unit, the surge wattage could be as few as 1.04 to 2.0 times its running wattage. In most cases the surge wattage won’t be an issue for you, but if you’ve got an older home in which the division circuits are already operating at their maximum safe capacity, the additional surge wattage might cause sporadic tripping of a circuit breaker.
Typical Surge Wattages
A 10,000 BTU Unit has surge wattage of 1800 watts along with a running wattage of 1200 watts. A 12,000 BTU unit has surge wattage of 3950 watts along with a running wattage of 3250 watts.