It's kWh not Kwh SI prefixes and units are case sensitive. "k" is the prefix for kilo; "K" is Kelvin. Similarly, "W" is Watt. "w", as far as I'm aware, doesn

It's kWh not Kwh SI prefixes and units are case sensitive. "k" is the prefix for kilo; "K" is Kelvin. Similarly, "W" is Watt. "w", as far as I'm aware, doesn't mean anything. "h" is the accepted symbol for the use of hour with the SI.