Are Solar Panels Worth It in 2026? How to Work Out Payback
The payback maths for a Hertfordshire home in 2026, using PVGIS generation data, the Ofgem price cap and current export rates, so you can run your own numbers.
Are Solar Panels Worth It in 2026? How to Work Out Payback
The Short Answer
For most Hertfordshire homes with a reasonably unshaded roof, yes. Whether it is worth it for your home comes down to three numbers you can check yourself. This guide walks through each one using published figures, so you can see how a payback estimate is built rather than taking one on trust.
Number 1: How Much Your Roof Will Generate
The European Commission's PVGIS tool models solar generation from satellite data covering 2005 to 2023. For a roof in St Albans at a 35° pitch, with 14% system losses, it estimates:
| Roof direction | Yearly generation per kW of panels | A 5kW system |
| South | 1,025 kWh | about 5,125 kWh |
| East | 821 kWh | about 4,105 kWh |
| West | 800 kWh | about 4,000 kWh |
A south-facing roof generates about a quarter more than an east or west one. East and west roofs still work; they simply take longer to pay back.
Number 2: What Each Unit You Use Is Worth
Every unit of solar electricity you use at home is a unit you do not buy from the grid. Under Ofgem's price cap for 1 October to 31 December 2026, the average electricity unit rate is 26.32p per kWh (Direct Debit, Great Britain average). The cap is reset every quarter and your own tariff may differ, so check your latest bill.
Number 3: What Each Unit You Export Is Worth
Electricity you do not use is exported and paid for under the Smart Export Guarantee (SEG). To be paid you need an MCS-certified installation and a smart export meter. Rates vary by supplier and can change with around 30 days' notice. Outgoing Octopus, a variable tariff, for example pays 12p per kWh after being cut from 15p on 1 March 2026. Our SEG rates guide compares the main options.
A Worked Example
Here is how the three numbers combine for a 5kW south-facing system in St Albans. How much of your generation you use at home depends on when you are in and what runs during the day, so the table shows two illustrative cases rather than a single promise.
| Use 40% at home | Use 60% at home |
| Generation | 5,125 kWh | 5,125 kWh |
| Used at home, at 26.32p | 2,050 kWh = £540 | 3,075 kWh = £809 |
| Exported, at 12p | 3,075 kWh = £369 | 2,050 kWh = £246 |
| Value per year | about £909 | about £1,055 |
Our guide price for the popular 5–6kW size is £7,000 to £11,000 installed, with 0% VAT on home installations until 31 March 2027. Taking £7,000 for a 5kW system, the simple payback is about 8 years at 40% home use, or about 7 years at 60%. Every extra £1,000 on the price adds roughly a year.
A simple payback leaves out future electricity price changes, the small fall in panel output each year and any finance costs, so treat it as a starting point for your own quote.
What Pushes the Numbers Up
1. Using more of your own generation — running the washing machine or dishwasher during the day moves you towards the 60% column.
2. An electric car or heat pump that can run on daytime solar instead of grid electricity.
3. A battery, which stores daytime surplus for the evening. It adds cost, so work out battery storage as a separate decision.
4. A south-facing roof — about a quarter more generation than east or west.
5. A time-of-use export tariff such as Outgoing Octopus Prime, which pays 16p per kWh between 4pm and 7pm and 9p at other times. It only beats a flat 12p if you can export in the evening, which usually means a battery. Octopus Flux is closed to new customers.
What Pushes Them Down
1. Shading from trees, chimneys or neighbouring buildings.
2. A north-facing roof, which generates less than any of the directions in the table above.
3. Low daytime electricity use, so more of your generation is exported at the lower export rate.
4. Paying too much — get more than one quote and check each installer on the MCS register.
When Solar Is Usually Not Worth It
- You expect to move within a few years
- Your roof is heavily shaded and there is no better alternative
- Your electricity use is very low
Work Out Your Own Numbers
Try our solar calculator, see how system size tracks usage in our cost by monthly kWh guide, or read about solar panels in Hertfordshire. Our free survey includes a roof assessment, shading analysis and a savings projection based on your own usage, with a no-obligation quote.
Sources: PVGIS 5.3 (European Commission Joint Research Centre), SARAH3 data 2005–2023, 35° pitch, 14% system losses; Ofgem energy price cap, 1 October to 31 December 2026; Octopus Energy export tariffs, checked August 2026.
