A 5kW solar system in the UK costs £6,500 to £9,000 fully installed in 2026, generates roughly 4,200 to 4,500 kWh per year, and can cut electricity bills by £600 to £900 annually with the right tariff.
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In short
A 5kW solar system in the UK costs £6,500 to £9,000 fully installed in 2026, generates roughly 4,200 to 4,500 kWh per year, and can cut electricity bills by £600 to £900 annually with the right tariff. There's no direct grant for solar panels, but 0% VAT runs until 31 March 2027, and ECO4 can fund the full cost for eligible benefits-receiving households in lower-rated homes.
A 5kW solar system can cover most of the daytime electricity use in a typical three or four-bedroom home. That's the short answer.
In practical terms, you're looking at around 12 to 14 panels on the roof, generating roughly 4,200 to 4,500 kWh per year in most of England and Wales. Scotland and the far north sit closer to 3,800 kWh. Cornwall and the south coast can push above 4,700.
That output runs your fridge, your washing machine, your dishwasher, your kettle, your laptops, your TV, and the heat pump if you have one, on a sunny day.
But here's the bit most installer brochures gloss over. Solar generates when the sun is up, and most UK households use most of their electricity in the evening. Without a battery, you'll export a big chunk of what your panels make and buy back electricity at night at full price.
So a 5kW system on its own is a strong starting point. Pair it with a battery (5kWh upwards) and you start covering 60 to 80% of your annual electricity demand. That's where the savings really stack up. See our guide on pair it with a battery for more detail.
For context on smaller systems and how they compare, our 4kW solar panel system guide breaks down the trade-offs at the next size down.
A 5kW solar system costs £6,500 to £9,000 fully installed in 2026, with most quotes landing around £7,500. Add £4,000 to £6,000 if you want a battery included.
Here's how the typical breakdown looks:
| Component | Cost range |
|---|---|
| Panels (12 to 14, 410W to 450W each) | £2,000 to £3,200 |
| Inverter (5kW string or hybrid) | £800 to £1,800 |
| Mounting, cabling, scaffolding | £1,200 to £1,800 |
| Labour and installation | £1,500 to £2,200 |
| Battery (5kWh, optional) | £4,000 to £6,000 |
| 0% VAT (until 31 March 2027) | applied automatically |
A few things drive price up. South-facing roofs with no shading and easy scaffolding access sit at the lower end. Complex roofs, two-storey houses with awkward access, integrated panels (where panels replace the tiles rather than sitting on top), or premium brands like SunPower and REC Alpha push you toward the £9,000 mark.
Don't pay 20% VAT. The 0% VAT relief on residential solar runs until 31 March 2027, and it applies to panels, batteries, inverters, and the install labour. If an installer quotes you VAT on a domestic system before that date, challenge it. They're either confused or trying it on.
We see quote spreads of £2,500 on identical systems. Get three quotes. Always.
A 5kW system suits homes with annual electricity use of 3,500 to 5,500 kWh, which covers most three and four-bed properties. Smaller homes overpay. Bigger users under-generate.
The quick sizing check: look at your most recent annual electricity bill, find your kWh usage, and aim for a system that generates 80 to 100% of that figure annually if you're planning a battery, or 50 to 70% if you're not (because you can only realistically self-consume that much without storage).
A two-person flat using 2,000 kWh a year doesn't need 5kW. You'd be exporting most of it at 5p to 15p per kWh while having spent £7,500 upfront. A 3kW system is the smarter buy.
A five-bedroom family home with an EV and a heat pump using 8,000 kWh a year needs more than 5kW. You'd cover maybe 50% of demand. Push to 6kW or 7kW if the roof allows.
Roof space matters too. Each 410W panel is roughly 1.7m by 1.1m. For 12 panels you need around 22 square metres of usable roof, ideally facing somewhere between south-east and south-west, with a pitch of 30 to 40 degrees and no chimney shadow eating the middle of the array.
If your roof is north-facing or heavily shaded, solar probably isn't the right move at all. Honesty matters more than a sale.
A 5kW system saves a typical UK household £600 to £900 a year without a battery, and £900 to £1,400 with one, based on 2026 electricity prices.
The maths runs roughly like this. Without a battery, you self-consume maybe 25 to 35% of what your panels generate (the daytime stuff, fridge, standby loads, daytime appliances). That's around 1,100 kWh used directly, worth about £300 at 27p per kWh. The remaining 3,100 kWh gets exported.
Export rates vary wildly. Octopus Energy's Outgoing Fixed tariff currently pays 15p per kWh. British Gas Export sits closer to 12p. Some smaller suppliers pay as little as 3p. That export income is anywhere from £100 to £450 a year.
Add it up: £400 to £750 saved without a battery, in the middle of the range.
A battery changes the picture. Self-consumption jumps to 70 to 80%. You're using almost everything your panels make, charging the battery during the day and discharging it in the evening when prices peak. Combine that with a smart tariff like Octopus Go or Cosy that charges the battery overnight at 7p to 10p per kWh, and the household savings can hit £1,400+ in a heavy-use home.
Payback periods sit at 8 to 12 years for panels alone, 9 to 13 years with a battery. Panels are warrantied for 25 years, so you're banking 12 to 17 years of pure savings after that.
The honest bit: nobody's getting rich off solar. But it's one of the few home upgrades that genuinely pays for itself, and the maths gets better every time energy prices rise.
There is no dedicated solar panel grant in the UK in 2026, but ECO4 can fund the full cost for eligible households, and 0% VAT applies to everyone.
ECO4 is the big one. If your household receives qualifying benefits (Universal Credit, Pension Credit, ESA, Income Support, or Child Benefit under certain income thresholds) and your home has an EPC rating of D, E, F, or G, ECO4 can fund a full solar installation at zero cost to you. The scheme runs until 31 December 2026 and is administered by the major energy suppliers. Each supplier has its own application process, which is annoying. Start with our ECO4 guide and our insulation grants overview for the eligibility detail.
0% VAT is the universal benefit. Everyone gets it, no income test, no forms. It saves £1,300 to £1,800 on a typical 5kW install. After 31 March 2027 the rate reverts to 5% unless extended.
The Smart Export Guarantee isn't a grant, but it's worth flagging. Every licensed energy supplier with more than 150,000 customers must offer an export tariff for surplus solar. Shop around. We mentioned Octopus's 15p above. Don't accept your existing supplier's rate without checking what else is out there.
What about the Boiler Upgrade Scheme or Warm Homes: Local Grant? Neither covers solar directly. BUS is heat pumps and biomass only. Warm Homes: Local Grant varies by council and a handful do fund solar (Cornwall is generous, parts of Greater Manchester are too), but most don't. Check with your local authority directly.
And the old Feed-in Tariff is closed to new applicants and has been since 2019. If anyone offers you a "government solar grant" in those terms, walk away. It doesn't exist.
Not sure which route applies to you? Run your details through our eligibility checker. Two minutes.
Ask five things: MCS certification, warranty terms, expected annual generation, export tariff guidance, and whether the quote includes scaffolding and DNO notification.
MCS certification is non-negotiable. You cannot claim Smart Export Guarantee payments or qualify for most grant routes without an MCS-certified install. Check the installer's number on the MCS register before signing anything. Plenty of cowboys claim certification they don't have.
Warranties matter more than people realise. Standard cover is 10 to 12 years on the inverter, 25 years on the panels (linear performance warranty), and 2 years on workmanship. Push for longer workmanship cover. Five years is achievable with the better installers.
Ask for the predicted annual generation in writing, with the assumptions behind it. A good installer will use MCS's MIS 3002 methodology and give you a kWh figure for your specific roof orientation, pitch, and shading. A bad installer will quote you a generic "4,500 kWh" without explaining how they got there.
Get export tariff guidance, not a hard sell. The best installers are tariff-agnostic and tell you the current top three SEG payers. The worst will push you to switch to a supplier they have a commercial relationship with.
And check what's in the quote. Scaffolding alone can be £600 to £1,200 on a two-storey house. DNO notification (telling the grid you're connecting a generator) is the installer's job for systems under 3.68kW per phase, but for a 5kW system you may need DNO approval beforehand, which can take 4 to 8 weeks. Some installers don't mention this until you've paid the deposit.
One last thing. Get three quotes. Not two. Three. We see price spreads of £2,000+ on identical specs from installers in the same town. The middle quote is usually the one to trust. The cheapest often cuts corners. The most expensive is often a national chain with overheads you don't need to fund.
For more on choosing an installer, see our solar panel installers guide.
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