Compute energy use E = P x t from appliance power and running time, together with the corresponding electricity cost.
E = P × t。
| Item | Formula / Rule | Source / Standard |
|---|---|---|
| Energy formula | E = P × t; power multiplied by time gives the energy consumed. | IEC 60050-131:2013 & ISO 80000-5:2019 |
| Unit conversion | One kilowatt-hour equals 3.6 MJ, or a 1000 W load running continuously for one hour. | ISO 80000-5:2019, thermodynamic quantities and units |
| Annual consumption estimate | Annual consumption is determined by rated power and annual operating hours, forming the energy baseline. | ISO 50001:2018, energy management systems |