Solar vs Mains Outdoor Lights: Which Is Best for UK Gardens?
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Verthara sells both solar and mains-powered outdoor lighting, and the honest answer to 'which is better for UK gardens?' is that they serve different jobs. Solar lights are installation-free, cost nothing to run, and work well from March to October in most UK locations. Mains lights give consistent output regardless of weather, work reliably in December, and can power fittings far brighter than solar will ever match. Pick the wrong type for the job and you'll either have dark garden paths in winter or an unnecessarily expensive electrician's bill for border accent lights.
How does solar outdoor lighting perform in the UK climate?
UK solar performance varies dramatically by season. London averages 4.5 peak sun hours per day in July but only 1.5 in December. Edinburgh gets less than 1.0 peak sun hour in December. This matters because solar lights charge their batteries during daylight and discharge them at night — the balance between charge input and overnight consumption determines whether the light works reliably.
| Month (London) | Avg. peak sun hours | Hours of darkness | Solar reliability |
|---|---|---|---|
| June | 5.5 hrs | ~8 hrs | Excellent |
| September | 3.5 hrs | ~12 hrs | Good (quality lights) |
| November | 1.8 hrs | ~15 hrs | Limited |
| December | 1.5 hrs | ~16 hrs | Unreliable for most units |
A quality solar light (2W panel, 2,500mAh lithium battery) can charge 5Wh of energy on a September day. Running a 1W LED for 10 hours consumes 10Wh — so even a good solar unit will run at reduced output or from battery reserves on cloudy autumn days. This isn't a flaw; it's physics. Plan accordingly.
How does mains outdoor lighting compare?
Mains lighting (240V or low-voltage 12V via transformer) delivers consistent, predictable output regardless of weather, season, or battery state. A 10W LED connected to mains produces 900 lumens on a grey December night in Edinburgh exactly as it does on a sunny July evening in London. This consistency matters for security lighting, entrance lighting, and any application where the light must work.
The trade-off is installation. A new outdoor 240V circuit costs £300–£800+ depending on run length and complexity, and requires a registered Part P electrician. Low-voltage 12V systems (transformer powered from an indoor socket) cost less — a 50W transformer runs around £40–£60 — and the 12V cable runs are safer for DIY. But they still require cable burial in gardens (minimum 600mm depth in beds, 450mm in paths under conduit per BS 7671).
Solar vs mains: direct comparison
| Factor | Solar | Mains (240V or 12V) |
|---|---|---|
| Installation cost | £0 (self-install) | £300–£800+ (electrician) or £80–£200 (12V DIY) |
| Running cost | £0 | ~2p per 10W per night |
| UK winter reliability | Reduced (especially Dec–Jan) | Consistent year-round |
| Max. lumen output | Up to ~1,000 lm (practical max) | Unlimited (20,000+ lm achievable) |
| Flexibility / repositioning | High — no cables to move | Low — cables are fixed |
| Battery replacement | Every 2–4 years (lithium) or 1–2 years (NiMH) | No battery |
Which garden lighting jobs suit solar? Which need mains?
Use solar for these jobs
Solar wins on decorative border lighting (spike uplights, flower border accents), garden path marking from spring to autumn, patio festoon and ambience lighting for social use, and any position where running cables would require digging up established planting. It's also the correct choice for any fitting that needs to be moved seasonally — a solar spike uplight repositioned from winter storage to spring borders in April is entirely practical.
Use mains for these jobs
Security and PIR floodlights — these must work on the darkest December night. Front entrance and door lighting — the path to your front door needs light when you arrive at 11pm in November. Any fitting that the household depends on reliably rather than aspirationally. Any position where the solar panel cannot get at least 2 hours of direct sun daily (north-facing walls, heavily shaded gardens).
Common mistakes when choosing between solar and mains
Using solar for security lighting
A solar PIR floodlight is a reasonable summer product. In December, when intruders are most active and daylight is shortest, it's unreliable. Fix: use mains-wired PIR floodlights for security applications.
Buying cheap solar lights and expecting year-round performance
Solar lights under £10 use NiMH batteries and 0.5W panels — inadequate for UK autumn and winter. Fix: spend £20–£40 per quality solar unit, choose lithium-ion cells and 1.5W+ panels.
Trying to DIY a mains 240V outdoor circuit
Outdoor mains wiring is Part P notifiable work. Unlicensed installations are uninsurable and dangerous. Fix: use low-voltage 12V systems for DIY garden runs; hire an electrician for 240V.
Placing solar panels in shade
A solar panel in shade all day will never charge the battery adequately. Even partial shade from a hedge or fence loses 40–60% of potential solar yield. Fix: always position the solar panel in the sunniest available spot, separate from the light fitting if possible.
Frequently asked questions
Are solar garden lights any good in the UK?
Quality solar lights (lithium-ion battery, 1.5W+ panel, IP65 rated) work well in the UK from March to October. Winter performance is limited in all but the sunniest southern UK locations. For decorative and ambience lighting they're excellent value; for security and critical entrance lighting, mains is more reliable year-round.
How much do mains outdoor lights cost to run in the UK?
At current UK electricity rates of approximately 24p/kWh, a 10W LED fitting running for 8 hours per night costs 1.92p — roughly £7 per year. A 10-fitting system (100W total) costs around £70 per year to run. LED fittings use 75–80% less energy than halogen equivalents, making mains LED running costs very low.
Can I convert solar garden lights to mains?
Not directly — solar fittings are designed for low-voltage DC power from the battery, while mains is 240V AC. The safest approach is to replace solar fittings with equivalent mains-rated fittings when mains reliability is needed. Some brands sell matching solar and mains versions of the same design.
What is low-voltage garden lighting and is it safe for DIY?
Low-voltage (12V) garden lighting uses a transformer to step mains 240V down to 12V DC or AC. The 12V output is safe to work with — a contact with 12V does not deliver a dangerous shock. Cable runs from the transformer to fittings can be installed by a competent homeowner. Only the transformer-to-mains connection (plugging the transformer in indoors) touches 240V — that requires only a standard socket, not an electrician.
How long do solar outdoor lights last?
The LED in a solar light typically lasts 20,000–30,000 hours. The battery is the limiting component — lithium-ion cells last 2–4 years (500+ cycles); NiMH cells last 1–2 years (200–300 cycles). After the battery fails, the fitting may be repairable if the battery is replaceable. Many integrated-battery solar lights are simply replaced at end of battery life.
Does Verthara sell both solar and mains outdoor lights?
Yes — Verthara carries both solar garden lights and mains-compatible outdoor fittings across wall lanterns, spike lights, post lights, and security floodlights. All carry CE certification and a 3-year manufacturer warranty. Free UK delivery on all orders, dispatched within 4–8 working days with same-day processing for orders placed before 12pm GMT.
Published by
Verthara Editorial Team
Every guide is researched by our editorial team using manufacturer specifications, UK wiring standards, and current market pricing. Content is reviewed before publication and updated when regulations or product availability change.