Peak wattage refers to the maximum electrical power output or capacity a device can supply for a short burst, usually measured in watts. This differs critically from continuous or rated wattage, which indicates power the device handles safely over extended periods.
Why this distinction matters: many devices draw far more power when starting up than during normal operation. A compressor, kettle, or air conditioning unit can surge to double or triple its normal power draw for milliseconds as motors accelerate or compressors kick in. Power supplies and uninterruptible power supplies (UPS) systems list peak wattage to ensure they can handle these brief spikes without shutting down or failing.
Common gotchas when buying power protection:
- Confusing peak with continuous wattage leads to undersized UPS systems that fail during surges
- Manufacturers sometimes emphasise peak figures to make products appear more capable than they actually are for sustained use
- The duration of peak power matters: a 1000W peak for 100 milliseconds differs entirely from 1000W peak for 5 seconds
- Multiple devices starting simultaneously can create cumulative peaks that exceed system capacity
When evaluating a UPS or power supply, check both figures. If protecting computers and office equipment, your continuous wattage requirement should sit at 60-70% of the device's rated continuous capacity, leaving headroom for peaks. For devices with motors or compressors, peak wattage matters most. Always account for simultaneous startup scenarios rather than assuming devices activate sequentially.