Solar Panel Savings Calculator UK

Solar panel savings in 2026: what you could save

Solar is the one household bill you can actually control. Every other cost on this site — gas, electricity, council tax, water — is set by someone else. With solar, once the system is paid off, the electricity it generates is effectively free. This solar panel savings calculator estimates how much you could take off your electricity bill, how much you could earn selling surplus power to the grid, and how long the panels take to pay for themselves.

The Energy Saving Trust reports that an average domestic system of around 4.5 kWp — roughly 12 panels needing about 20-30 m² of roof, costing about £6,100 installed — can save a typical home in the region of £750 a year, and up to around £1100 for a larger system on a home that uses more of its own daytime power. At the same time it cuts around 1tonne of CO₂ a year.

Panels are a long-lived asset. Good-quality modules typically last 25 years or more, though the inverter usually needs replacing after about 12years. That means a system that pays back in 8–12 years then goes on generating largely free electricity for another decade or more. Solar sits alongside your other running costs, so it is worth weighing against your electricity bill calculator and gas and electric bill calculator figures when you budget for the year.

The figures below are illustrative and use verified 2026 primary-source numbers. For a firm price you should get quotes from at least three MCS-certified installers, since MCS certification is also a condition of claiming export payments under the Smart Export Guarantee.

How solar panels cut your bills: self-use and export

Your solar saving comes from two separate places, and it helps to think of them apart. The first, and by far the bigger, is self-consumption: every unit you generate and use in the home is a unit you do not buy from the grid. Under the Ofgem price cap for Q3 2026, the GB average electricity import rate is about 26.11p per kWh, so each self-used unit is worth that full 26.11p to you.

The second is export: any surplus you generate but do not use is sold back to the grid through Ofgem’s Smart Export Guarantee (SEG). Export rates are far lower than the import rate — typically around 12p to 13p per kWh on a flat tariff, though the best time-of-use export tariffs can pay 15–20p or more at peak times. Because a self-used unit is worth roughly twice an exported one, the single biggest lever on your return is using more of your own solar rather than exporting it.

Without a battery, a typical home uses only about 40–50% of what its panels generate, exporting the rest. Shifting daytime loads — running the dishwasher, washing machine or an immersion heater while the sun is out — lifts that self-use share and improves the payback. This is exactly why a south-facing roof, or an east/west split that spreads generation across the day, matters: an east/west array loses around 15-20% of total output versus due south, but spreads it into the morning and evening when you are more likely to use it.

If you are weighing solar against moving to a more efficient home, the energy rating also affects running costs. You can sense-check that with the EPC monthly cost calculator and see your whole picture on the household bills calculator.

Solar system size vs generation, saving and payback

The table below shows how a typical UK home’s numbers change with system size, from a compact 3 kWp array up to a large 6 kWp system. Annual generation assumes a well-oriented, largely unshaded south-facing roof (roughly 850 kWh per kWp per year in the UK). The estimated saving blends self-consumption avoided at about 26.11p per kWh with surplus exported at about 12p per kWh under the Smart Export Guarantee. Install costs reflect the current 0% VAT on domestic solar.

Source: Energy Saving Trust solar advice and Ofgem Smart Export Guarantee — figures illustrative, 2026.

The pattern is clear: bigger systems generate and save more in absolute terms, while payback stays broadly similar because cost and saving scale together. The sweet spot for most households is the 4.5kWp system, but if you have a large roof, high daytime usage, or plan to add an EV or battery, a 5–6 kWp array often makes better long-term sense. Council tax and other fixed bills do not move with solar, so keep them in view with the council tax calculator when you plan.

The Smart Export Guarantee (SEG) explained

The Smart Export Guarantee is the mechanism that pays you for surplus solar. It replaced the old Feed-in Tariff for new installations and is administered by Ofgem, which requires every licensed supplier with more than 150,000 customers to offer at least one SEG export tariff. Smaller suppliers can offer one voluntarily. Because it is a competitive market, rates vary widely between suppliers.

A typical flat SEG rate in 2026 is around 12p per kWh, with the market average close to 13p per kWh. The most generous time-of-use export tariffs pay considerably more during peak demand periods, so it is worth shopping around — you do not have to buy your import electricity from the same company that pays your export, though some suppliers offer better export rates to their own import customers.

What you need to claim SEG

To qualify you need a solar system of 5 MW or less installed by an MCS-certified installer, and a smart or export meter capable of recording your exports half-hourly. Without a meter that measures actual export, some suppliers estimate it, but a smart meter almost always gets you a better deal. The SEG applies across England, Scotland and Wales.

Source: Ofgem — Smart Export Guarantee

Battery storage: is it worth adding?

A home battery stores the solar you generate during the day so you can use it in the evening, instead of exporting it cheaply and buying it back expensively. Because self-used power is worth about 26.11p per kWh while exported power earns only around 12p, a battery can lift the share of your own generation you use from roughly 40–50% to 70–80%, adding meaningfully to your annual saving.

The trade-off is cost. A domestic battery typically adds £5,000 to £8,000 to the installation, which lengthens the overall payback period, and most batteries carry a warranty of around 10 years. Batteries make the strongest case where you are out of the house during the day (so you would otherwise export most of your generation), where you plan to charge an electric vehicle, or where you want backup power during outages. Many owners also use a battery to charge cheaply overnight on a low-cost off-peak tariff and discharge during peak hours — a saving that has nothing to do with solar at all.

If your main goal is simply to cut the electricity bill as fast as possible, panels alone usually give the shorter payback; a battery is best seen as a way to raise your self-sufficiency and resilience rather than to speed up the return. Compare the effect on your day-to-day costs with the gas bill calculator if you are also thinking about electrifying heating.

0% VAT on domestic solar until March 2027

One of the biggest current incentives is the VAT relief. Domestic solar panel installations — and the batteries fitted with them — carry 0% VAT in England, Scotland and Wales as an energy-saving material. On a £6,100 system, that relief is worth several hundred pounds versus the standard 20% rate, which is already baked into the install costs shown in the table above.

The relief is time-limited. Under current rules the 0% rate applies until 31 March 2027, after which the rate is scheduled to revert to a reduced 5%. If you are already planning to install, doing so before the deadline locks in the saving. The relief covers the supply and installation of the qualifying materials, so it is applied by your installer rather than something you claim back yourself.

Source: GOV.UK — VAT on energy-saving materials (Notice 708/6)

Is solar worth it in 2026?

For most homes with a reasonable roof, the answer is yes — but it depends on your circumstances. Solar works best where you have an unshaded south, south-east or south-west-facing roof, use a fair amount of electricity during daylight hours, plan to stay in the home for at least the payback period, and can either pay upfront or borrow cheaply. In those conditions a 4.5 kWp system saving around £750–£1100 a year, paying back in 8–12 years, and then running largely free for another decade is a solid return.

It is less compelling where the roof is heavily shaded or north-facing, where the household is out all day and would export most of its generation without a battery, or where you expect to move within a few years. Even then, solar can add value to the property and provides a hedge against future rises in the electricity price cap — which is exactly the cost you avoid every time you use your own power.

Before committing, get at least three quotes from MCS-certified installers, check that each quote spells out the expected annual generation, the self-consumption assumption and the SEG tariff, and be wary of headline saving figures that assume you use 100% of what you generate. Use the calculator above as a sanity check, and revisit your wider budget on the household bills calculator once you have firm numbers.

Solar panel savings calculator: frequently asked questions

Everything you need to know about solar panel savings, the Smart Export Guarantee, payback periods and battery storage for a UK home in 2026.