How can you tell if something is energy efficient based on watts and volts?

Question

I live in a van and have only a certain amount of energy I can use each day but can never tell what appliances are efficient or not. HELP

In: 1

Answer 1

Volts should be the same for all the items in your van: probably 12 or 24V. The exception would be anything run off an inverter which will be at 230V.

Watt is the unit of power, and power multiplied by time is energy. So something that consumes 50W for 2.4 hours is using the same energy as something that draws 5W for 24 hours.

Efficiency is rather harder to determine, but I suspect that isn’t really what you care about?