Solar
For a typical UK roof at 2026 prices, a well-sized array on a smart tariff pays for itself around year eight and then quietly compounds for the rest of the panel warranty. The chart below is the shape of that maths.
Cumulative return (£)
Years from install
Install cost
£6,800
6 to 8 panels + inverter
Payback year
Year 8
At 2026 tariffs, no battery uplift
Return by year 15
+£11,950
Warranty typically covers 25
The honest question
Are solar panels a good financial and environmental decision for a UK home in 2026?
The short verdict
For a house with a mostly unshaded south, east or west-facing roof and a daytime electricity load worth talking about, yes; a right-sized array pays back inside seven to ten years and then produces cheap electricity for another fifteen. For a shaded roof, a heavy north-only aspect, or a household that is out of the house every daylight hour with no battery, the maths gets weaker and needs to be run honestly rather than sold enthusiastically.
The electricity bill keeps climbing and the roof is sitting empty.
Draught-proofing, LED lighting, standby audits and moving the biggest loads to off-peak hours saves a meaningful amount before any capital spend. Solar earns its money against real consumption, not brochure consumption.
A wide off-peak spread (Octopus Cosy, Go or Agile) can lower the bill enough that the solar case has to earn its keep against a different baseline. Worth pricing before ordering panels.
If you've considered these and solar is still the right answer for your home, here's how to choose well.
With a right-sized array on the right roof, solar generates cheaper electricity on a house you already own for 25 years. Size to how you actually use power, not to fill the roof; battery and export decisions come after.
The decision, in six questions
Six questions decide whether solar is a strong candidate for your house, worth considering with caveats, or the wrong shape of investment.
Is your roof mostly unshaded between 10am and 4pm, and facing somewhere between east and west through south?
The physical case is strong; the buy is now about sizing and specification.
Strong candidate
A shaded roof or a hard north-facing aspect is where solar disappoints; the case has to earn its keep on other grounds.
Worth considering
Is anyone home during daylight hours on most days, or can you shift laundry, dishwashing and hot-water heating into daylight?
Self-consumption climbs from 25 per cent to 50 per cent without any battery spend; the payback maths tightens sharply.
Strong candidate
Empty-house households need a battery for solar to pay back on time; treat the two as one decision, not two.
Worth considering
Do you own the property, and plan to be in it for at least seven years?
The payback window sits comfortably inside the ownership horizon.
Strong candidate
Under seven years the maths gets tight; a well-installed array does add to sale value but the direct return is compressed.
Worth considering
Is the roof structure sound and the covering good for another 15 years, or is a re-roof due within five?
Fit solar now; the panels sit on the covering for their whole life.
Strong candidate
Re-roof first, then fit solar onto the new covering. Removing and refitting panels for a re-roof costs £600 to £1,500 and is avoidable.
Probably not for your home
Is your annual electricity consumption above 2,500 kWh, or do you plan to add a heat pump, EV or hot-water heating from electricity in the next few years?
There is real daytime load for the array to displace; the maths sits at the strong end of the range.
Strong candidate
A very small household with low electricity use is a weaker case; the array is largely selling to the grid, not offsetting expensive retail units.
Worth considering
Are you happy running the numbers on your actual consumption, or do you want the installer's payback figure taken at face value?
Insist on a system sized to your real half-hourly load; that is where a good installer proves themselves.
Strong candidate
Installers' generic payback figures assume best-case self-consumption; ask for the model against your smart-meter data or add roughly two years to their quoted payback.
Worth considering
What usually changes the answer
Change one of these and our recommendation often changes with it.
You are planning a heat pump in the next two to three years.
What changes
You have an EV or plan to get one, and you can charge at home during daylight or via a time-of-use tariff.
What changes
The roof is heavily shaded by a neighbour's tree, a chimney or a taller adjacent building.
What changes
You live in a listed building or a conservation area.
What changes
The property is rented out or bought as a buy-to-let.
What changes
You are considering export tariffs (SEG) as part of the case.
What changes
The house sits far north (northern Scotland, the Highlands, coastal Northumberland).
What changes
If this were our house
For a UK 3-bed semi with a south-facing rear roof, one adult working from home three days a week and an EV on the driveway
We would fit an unshaded 5 to 6kW array on the south-facing rear roof and stop there for phase one. That is enough to cover the daytime baseline, the EV's daylight-hour top-ups on the working-from-home days, and the summer heat-water heating via a simple immersion diverter. We would not fill the east-facing front roof at the same time; the marginal panels there earn a lot less than the ones on the south, and the case for filling them is much stronger once a battery has been added and consumption patterns are known.
We would run the array without a battery for the first summer, watch the self-consumption figure on the app, and only then decide the battery size. Most households discover their real self-consumption is higher than the installer's default assumption, which changes the battery decision. If the consumption profile is as expected, we would add a 10 to 13kWh battery in year two and split the case for that spend against both solar surplus storage and off-peak tariff arbitrage; not against solar alone.
When we'd say no
We would rather lose the sale than take you somewhere the numbers don't stand up.
You are being sold a 6kW array for a household using 2,000 kWh a year with no plans for a heat pump or an EV. You will export three-quarters of what the panels make at 5 to 15 pence, while paying 28 pence for the units you import in winter; the maths does not work.
The roof is heavily shaded for the middle four hours of the day and the installer is not proposing power-optimisers or micro-inverters. A single string inverter on a shaded roof loses far more than the shaded panel would; the specification is wrong for the roof.
The roof needs re-covering within the next five years. Fit the roof first, then the panels; removing and refitting an array to allow a re-roof costs £600 to £1,500 and is avoidable.
The quote is for an in-roof integrated system on a house that does not have a planning constraint requiring it. In-roof systems are a 20 to 40 per cent premium for a look; on a house that would accept on-roof panels, the extra spend is aesthetic, not functional.
You are on a two or three-year ownership horizon and the installer's payback figure is being quoted at nine years. The maths does not close inside your window unless the sale-value uplift is credible in your local market; get that verified independently before signing.
The installer will not model the shade on your specific roof with a proper shading tool (drone survey, PVGIS, HelioScope). Generic tables miss stripe-shading and are the single biggest source of over-quoted generation.
What most people get wrong
The trade at a glance
A five-step editorial scale, not a rating. Green weight is a gain; grey weight is a cost you carry.
Up-front cost
£4,500 to £8,500 for a 4 to 6kW array installed on a competent roof at 2026 UK prices; £8,500 to £14,000 for 6 to 10kW.
Annual generation (typical UK 4kW array)
3,400 to 3,800 kWh a year depending on roof pitch, orientation, latitude and shade; equivalent to roughly £600 to £900 of retail electricity at 50 per cent self-consumption.
Self-consumption without changes
25 to 35 per cent for a default household; the rest is exported at 5 to 15 pence.
Self-consumption with load-shifting and a battery
70 to 85 per cent with a right-sized battery and time-of-use scheduling; the number that transforms the payback.
Payback period
7 to 10 years for a competent install on a right-sized array; 5 to 7 years with a battery and time-of-use tariff on a house with real daytime load.
Lifespan
Panels are warranted at 25 to 30 years and typically produce 80 per cent of their day-one output at year 25; inverters last 10 to 15 years and are a mid-life replacement.
Install disruption
One to two days on the roof, half a day inside for the inverter and cabling; no plaster damage in most cases.
Maintenance burden
A visual check every few years; occasional bird-proofing on the array; inverter replacement mid-life. That is the whole list.
What it costs
Small semi or town house; enough for a low-consumption household with modest daytime load.
The most common size for a 3-bed semi; roughly 3,400 to 3,800 kWh a year.
The right size for a household with a heat pump, EV or full-time home working; typically 4,700 to 5,700 kWh a year.
Larger detached and modern-detached homes; usually justified by a heat pump plus EV plus daytime consumption together.
For heritage or planning constraints, or where the on-roof aesthetic is refused; a real premium for a look.
Often omitted from the quote and worth insisting on; pigeon nesting under panels is the single biggest post-install complaint.
At 2026 export tariff rates; higher on Octopus Flux or similar time-of-day export tariffs.
Budget for a mid-life inverter change; hybrid inverters at the top of the range.
Panels are largely self-cleaning in the UK climate; the only recurring spend is occasional bird-proofing or a soft wash for coastal soiling.
Ranges triangulated from MCS-registered installer quotes across the UK in 2025 to 2026, Energy Saving Trust generation figures, PVGIS location-specific yield modelling and SEG tariff data from Octopus, EDF, OVO and E.ON. Refreshed each spring before the season. Your figure depends on roof orientation, shade, latitude and how the household uses the output.
You've got the answer
On a competent roof with a household happy to shift some load into daylight hours, or with a right-sized battery, solar is one of the strongest capital investments available to a UK homeowner in 2026; typical paybacks land at seven to ten years for solar-only, five to seven with a battery and time-of-use tariff, and the array then produces cheap electricity for another fifteen. The case weakens sharply on heavily shaded roofs or in very-low-consumption households; get the shade modelled properly and the sizing done against your real half-hourly data.
You can stop here if you're still deciding. The rest of this page is for readers who have already committed and want to spend the money well.
If you're going ahead
This half of the page is written for the reader who has decided. It reads in the order the decisions come at you.
Which version
Panels mounted on rails above the existing roof covering, wired in series into a single string inverter in the loft or garage. The default UK domestic install; cheapest per watt, robust and well understood.
When we'd choose it
Any unshaded roof with a clean single-plane aspect. Roughly two-thirds of UK domestic installs fit this pattern.
Each panel has its own DC optimiser or micro-inverter, allowing each to operate at its own maximum power point independently. Adds £60 to £120 per panel; recovers 5 to 20 per cent of generation on any array where shade would otherwise pull the whole string down.
When we'd choose it
Any roof with partial shade from a chimney, dormer, tree or neighbour's building; also multi-orientation arrays where east and west panels share an inverter with south panels.
Panels replacing the roof covering rather than sitting above it; flush with the roofline. A 20 to 40 per cent premium over on-roof; genuinely tidier look and, on a re-roof, no double-spend on tiles under panels.
When we'd choose it
Heritage or planning-constrained houses where on-roof panels would be refused, and any project doing a full re-roof at the same time.
Each tile or slate carries a small PV cell; the whole roof looks like a slate roof from the ground. Significant premium (roughly double the £/kW of on-roof) and lower generation per m² than conventional panels, but the aesthetic case is real.
When we'd choose it
Listed buildings and conservation-area houses where visible arrays are refused, and clients where aesthetic is worth the premium. Rarely the right buy on economics alone.
A single inverter that handles both the solar array and (later or now) a DC-coupled battery. Small premium over a solar-only inverter; avoids duplicate hardware if a battery is added later.
When we'd choose it
Any household that plans to add a battery within five years; the marginal cost is small and the retrofit is much cleaner.
Your house
South at 30 to 40 degrees is the theoretical optimum for the UK; east or west at similar pitches produce 80 to 85 per cent of the south figure. Flatter pitches (15 to 25 degrees) lose a few per cent in winter and gain a few in summer, which usually matches household use fine. Shallow flat roofs need ballasted or angled frames; north-facing pitches are almost never worth the panels.
Multi-orientation arrays (east and west, or south and east) can deliver higher self-consumption than a same-total south-only array, because generation spreads across more hours of the day.
A single stripe of shade across one panel for four hours a day, if the inverter is a plain string inverter, can pull the output of the whole string down disproportionately. Power-optimisers or micro-inverters isolate the shaded panel and recover most of the loss.
Insist on a proper shade model (drone survey, PVGIS or HelioScope) before signing; installer-eye-only shade assessment is the single biggest source of over-quoted generation.
A working-from-home household or a household with children at home during the day self-consumes more of the array's output at retail prices; an empty-house household exports most of it at export prices. The gap is roughly £150 to £400 a year on a 4kW array; large enough to move the payback by two years.
Load-shifting (running the dishwasher and washing machine on daylight timers, heating hot water via an immersion diverter in the middle of the day) is free and pushes self-consumption from 25 per cent to 45 per cent typical.
A heat pump triples winter electricity load and is largely uncorrelated with solar output; the array offsets summer hot-water demand but not the winter heating spike. An EV, by contrast, correlates strongly with daytime solar if charging is scheduled to daylight hours; this is where oversized arrays start to earn.
Plan the electrification you know is coming when sizing the array; retrofit expansions later are more expensive per panel than adding capacity up front.
Panels weigh 10 to 15 kg per m²; nearly all modern UK roofs carry this without issue, but timber-framed cottage roofs and some concrete-tile roofs at the edge of their loading tolerance need a structural check. Ask for the installer's structural sign-off, not just the wind-load calc.
If the roof covering has fewer than 15 years of life left, re-cover before fitting solar; removing and refitting an array for a re-roof costs £600 to £1,500 and is easily avoided by sequencing the work.
In use
Sunlight liberates electrons in a silicon lattice, generating direct current at panel-level voltages of 30 to 50V. A modern monocrystalline panel converts 20 to 22 per cent of the sunlight hitting it into electricity; higher-tier panels reach 22 to 23 per cent, cheaper panels 18 to 20.
A string inverter takes the combined DC output from a series of panels and converts it to 230V AC synchronised with the grid. Modern inverters run at 96 to 98 per cent conversion efficiency and last 10 to 15 years. Hybrid inverters do the same job while also managing a battery on the DC side.
Generated electricity is used first by the house at the moment it is produced; whatever the house does not use is exported to the grid via the smart meter. A generation meter (or the inverter's own logging) records total production; the smart meter records net import and export. Payback maths uses all three figures; installers who only quote generation without self-consumption are quoting the easy half.
G99 regulations require domestic solar to shut down automatically when the grid fails, to protect linesmen working on the network. This is why solar alone does not power the house through a power cut; only a battery with a specified EPS circuit provides backup, and this is a separate specification choice.
Common mistakes
Array sized to fill the roof rather than to household consumption; export share climbs, self-consumption stays low, payback stretches beyond the quoted figure.
Shade not modelled properly; a chimney or a neighbour's tree pulls 15 to 25 per cent off the annual figure and the owner blames the panels.
String inverter used on a partially shaded roof where power-optimisers were needed; a single shaded panel drags the whole string down disproportionately.
Bird-proofing omitted; pigeons nest under the panels within eighteen months and the noise and mess become the household's biggest complaint.
Installer's payback figure quoted against best-case self-consumption; real household consumption pattern is different and the payback lands two years later than promised.
Roof re-covered five years after solar was fitted, requiring the array to be removed and refitted at £600 to £1,500 avoidable spend.
Battery bolted on later with a non-hybrid inverter; a second inverter is needed and the installation is messier than it would have been with a hybrid at day one.
Owner expects the system to power the house through a blackout without an EPS circuit; disappointment when it shuts down at the first power cut.
The installer
The gap between the best and worst installer on this list of trades is larger than the gap between products. Judge the person, not the brochure.
Maintenance
Panels are largely self-cleaning in UK rainfall. A visual inspection every three to five years checks for pigeon nesting, moss growth on frames and any degraded connectors; a proper installer offers this as a service call at £80 to £180. The inverter is the mid-life replacement; expect to change it at year 12 to 15 at £800 to £1,600. Monitoring apps flag any panel-level or string-level underperformance; check the app every few months rather than only when the bill looks odd. Whole-system life is 25 to 30 years for the panels, one inverter replacement, and one or two connector checks.
Real questions
On an unshaded south, east or west-facing roof, with a household happy to shift some load into daylight hours or add a battery, solar is one of the strongest capital investments available to a UK homeowner in 2026. Typical paybacks: seven to ten years for solar-only, five to seven years with a battery and time-of-use tariff. The case weakens sharply on heavily shaded roofs and in very-low-consumption households; get the shade modelled properly and the array sized against your real smart-meter data, not a national average.
Solar's economics tighten sharply with a right-sized battery; the two are usually one decision rather than two. Ten minutes on that page tells you whether the battery half of the maths works for your household, and when to add it.