Your article suggests that a 4 kilowatt (kW) solar panel system can save its owners £980 a year at 28p per kilowatt hour (kWh) and £1,575 at the 45p per kWh that is coming soon (Solar panels: how to fix your energy bills while the sun shines, 20 August). This estimate overlooks the important fact that most electricity is produced in summer, and all of it in daylight, while most consumption is in winter and at night.
Our 4kW system has produced about 4,000kWh a year for the last 10 years. Although that is equivalent to our annual consumption we only consume about 30% of what we produce, despite having a household of three stay-at-home pensioners and electric cooking and water heating.
