Katie59
A 4 kw solar panel is likely to produce 3000kwh a year in the UK
Of that 2000 will be exported at say 6p. £120
Only 1000 are likely to be used at 20p £200
The amount of solar you can use depends when you are using power, doing washing and cooking mid day helps, car charging during the day will use most of the available solar when the sun shines.
Moving normal domestic routine to when the sun shines is not likely to give a good return on Solar, you need a way of using more, an EV to charge (slowly), maybe air conditioning in hot weather. So unless you have a way of using most of the solar you will break even in 15 to 20 yrs, depending on running costs, if £5000 in invested in a pension etc at a modest 5% you will get back over £13000 in 20yrs.
I’m not anti solar, the real benefit is commercial solar where most power is used during the day, refrigeration or factory processes.
Sorry. I'm obviously being thick here. Where can you get an interest rate of a "modest" 5% on £5000 at the moment? You'd be lucky to get 1-2%, which wouldn't give anything like a return of £13,000 in 20 years.
If you have £5000 to invest and buy solar panels, the "cost" is the loss of up to £100 a year in lost interest offset against the saving in electricity, which is likely to be more, according to your own figures. Use the profit to set aside the difference between actual electricity bills and what they would be without solar panels. With electricity prices projected to rise even more, the break even point will come sooner.