Is 1,000 kWh a month a lot?

A bit above the US residential average of about 900 kWh, and normal for a family home with central AC. Under 600 is a small or efficient household; over 1,500 usually means electric heat, a pool, or an EV in the mix.

Should I size solar off my highest bill?

No, off the 12-month average, because net metering (where available) banks summer overproduction against winter. Sizing to the August peak buys panels that mostly generate surplus sold back at whatever your utility pays for exports, which is often less than retail.

Finding the kWh number that should size your system

Every number on this site keys off one figure: kilowatt-hours per month, from your electric bill. It is usually hiding in plain sight, one month of it will lie to you, and ten minutes with a year of bills is worth more than any square-footage estimate ever printed.

Where it is on the bill

Look for "kWh used," "total usage," or a meter-readings pair (present minus previous reading = the month's kWh). It is not the dollar total, and it is not kW. That distinction matters: kW is speed, kWh is distance. A bill of $180 tells you about your utility's rates; 1,240 kWh tells you about your house. Most utility portals will also hand you a 12- or 24-month usage chart, which is the whole exercise done for you.

Why one month lies

Pull your July bill and you size for the AC; pull April and you size for a house on its best behavior. Between an AC-heavy summer and a mild shoulder month the same home can swing 2x. The honest input is the 12-month average: add a year of kWh, divide by 12. If you only have a few bills, be seasonal about it. A single winter bill from a gas-heated home is close to the annual average; a single August bill from a Phoenix home is nowhere near it.

Adjust for the future, not the past

Panels last 25-plus years; your usage won't sit still. Add the loads you already know are coming, with planning figures: an EV commuting the national-average 37 miles a day adds about 360 kWh a month (our EV page does the panel math), a heat-pump conversion adds winter kWh where a gas furnace used to burn therms, a pool adds its pump. Subtract known departures too, like the teenager taking the 40-minute showers to college. Utilities that cap system size at historical usage will want documentation for upsizing, and an EV purchase order usually satisfies them.

Then the math is short

Monthly kWh ÷ 30.4 = daily kWh. Daily kWh ÷ (panel kW × your state's peak sun hours × 0.77) = panel count, round up. The calculator does it live, and the answer transfers straight onto any quote: a bid whose kW times your sun figure times 0.77 doesn't reach your daily kWh isn't covering your bill, whatever the brochure says.