Running cost questions

How do I read my electricity price off the bill?

Find the supply or generation charge and the delivery charge, add them, and divide by the kilowatt hours used in the period. Many bills show an all-in effective rate near the summary box. If the bill lists several rates, use the one that applies to the hours you run the device.

Why does the result differ from my last bill?

Because the device is one line among many. A space heater at $38 a month can be a quarter of a small bill and a tenth of a large one. The share field shows which.

Does a higher wattage device always cost more to run?

No. A 3,000 W dryer run for one hour costs less than a 1,500 W heater that runs for four hours. Wattage sets the rate; hours set the total.

Is a 1,500 W heater cheaper to run than a 2,000 W heater?

Only in the sense that it heats less. Heat output tracks electrical input almost exactly, so a higher wattage heater costs more per hour and delivers more heat. Neither is cheaper per unit of warmth.

What is a kilowatt hour?

A kilowatt held for an hour. A 1,000 W appliance for one hour is 1 kWh. A 100 W appliance for ten hours is also 1 kWh. The bill counts kilowatt hours, never watts.

Should I use the label wattage or a meter reading?

A meter reading, if you have one, because labels state worst-case draw. Without a meter, the label is the closest thing to a measured number and it is usually within 20 percent for resistive appliances like heaters and kettles.