SolarSums

When your panels make power, and when you use it

Solar panels make most of their power around the middle of the day, and many homes use more of theirs in the evening. The first chart shows that gap on an average day in each month, where you live. Move through the year to see how a short December day compares with a long June one, then drag the battery slider to see how much of the evening a battery could cover.

Showing Leeds (LS1 4AP) until you enter a postcode.

Your year, month by month

Bar chart of solar generation for each month, split into used at home, used later from the battery and exported, with a line for household electricity use. Tap or drag across the chart to pick a month.

Each month's solar is split three ways: used straight away, used later from the battery, and exported. The line shows what your home uses that month. Move the battery slider and watch more of the summer surplus move from exported to used.

Used straight away Used later from battery Exported Household use

Solar a year
–
Used at home
–
Exported
–
Self-consumption
–
Use covered by solar
–
Battery topped up off-peak
–

Your system

Roof faces

Roof pitch is set to 35 degrees, the same as the calculator's default.

An average day in June

Line chart of solar generation through an average day in the chosen month, with household use as bars, in UK clock time.

The curve is what your panels make through an average day in the month you've picked. The bars are what your home uses each hour. The shaded evening hours are the part a battery could cover from power saved earlier in the day. Lighter shading marks power you don't use at the time.

Solar generation Not used at the time Household use Covered by battery

Solar per day
–
Used per day
–
Used straight away
–
Used later from the battery
–
Exported
–
Off-peak to battery
–

How this works

  • Sun data comes from PVGIS, the European Commission's free solar tool, for your postcode, with the same 14% system loss as our calculator.
  • Each day is an average for that month, not a forecast for a particular day. Cloudy and sunny days will vary either side of it.
  • Household use follows the same split as the calculator: 35% in the day, 45% in the evening and 20% overnight.
  • Power your panels make that you don't use at the time is stored in the battery if you have one, and exported once it's full.
  • A battery is modelled at 90% round-trip efficiency, using the same maths as the calculator, so the two tools agree.
  • A battery can also top up overnight on cheap off-peak power, as in the calculator.
  • The chart uses a fixed 35° roof pitch and lets you pick which way the roof faces.
  • Nearby postcodes within about 10 km share one set of figures. Shading from trees or buildings isn't modelled.

These figures are an illustration to help you understand your options, not financial advice or a quote.

Want to know whether it pays back? Open the calculator for costs, savings and payback.