How to read your electricity bill before going solar

Kilowatt-hours (kWh): how much you use

A kilowatt-hour is the unit of energy you are billed for. Running a 1,000-watt appliance for one hour uses 1 kWh. Your bill shows the kWh consumed in the billing period, usually about a month.

The rate per kWh

Divide your total bill by the kWh used to get a rough average cost per kWh. Rates change from month to month and include several charges and taxes, so use a recent bill, or several, rather than one month.

Your usage pattern

Look at the last several months. Do you use more in hot months? Solar sizing is based on a typical month, not the highest or lowest one. Also think about when you use power: panels only produce during the day.

What to bring to an assessment

• Your last few electricity bills.
• A rough list of major appliances (aircon, pumps, refrigerator).
• Photos of your roof and electrical panel if you have them.
• Whether you want savings, backup, or both.

A caution about savings figures

Estimates, including our own estimator, depend on assumptions such as the electricity rate and how much of your use is during the day. Real savings can only be confirmed after an assessment of your property and the utility's current rules.