What is meant by the terms “continuous wattage” and “peak surge wattage” on the inverters?

The “continuous wattage” is the wattage that the inverter can supply 24/7 as long as the DC input power supply is in good condition (usually, the DC power supply is a car battery). The “peak surge wattage” is the maximum wattage that the inverter can supply for very short period of time (a split of a second)

NOTE: Induction motors such as air conditioners, refrigerators, freezers, microwave ovens, and pumps may have a start up surge of 3 to 7 times the continuous rating. Heat generating appliances such as hair dryers and water heaters will have high peak surges as well.

Example: If the microwave oven has peak surge which is 4 times the continuous wattage, the 1200 Watt continuous microwave ovens will have 4 x 1200 Watts = 4800 Watts peak surge. The recommended inverter to run 1200 Watt continuous and 4800 Watt peak surge microwave is 2500/5000 Watt inverter or larger. In general, induction motors require an initial surge of power to start up (“starting load” or “peak load”). Once started, the tool or appliance requires less power to continue to operate (“continuous load”).