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Solar Panel Replacement Cost Calculator (UK)

Free UK solar panel replacement cost calculator. Work out labour, materials, MCS recycling and call-out costs and compare against a full new MCS install.

Solar Panel Replacement Cost Calculator

Material cost
£689
Labour cost
£422
Disposal cost
£72
Total replacement cost
£1,183
Cost per panel replaced
£296
Cost per replaced watt
£1/W
Full new-system equivalent
£2,788
Replace vs full system
42.4%

How to use this calculator

Eight inputs and the tool returns a full UK-priced quote breakdown plus a comparison against the current MCS-installed price per watt for a brand new system:

  1. Panels to replace — number of failing or underperforming modules.
  2. New panel wattage — typical 2026 tier-1 modules sold in the UK are 405 W to 435 W.
  3. New panel price (£/W) — wholesale runs £0.38 to £0.45, retail with markup £0.42 to £0.50.
  4. Labour hours per panel — first panel takes 1.5 hours including setup; subsequent panels 0.7 to 0.9 hours on the same visit.
  5. Installer labour rate (£/h) — billed van rate, typically £50 to £75 in the UK; central London £80 to £100.
  6. Disposal fee per old panel (£) — £15 to £25 at PV CYCLE UK or Recolight partner.
  7. Call-out / van charge — fixed one-off, £150 to £220 in most regions.
  8. New full system reference (£/W) — current MCS-installed cost of a fresh residential array, about £1.65 to £1.85/W per the most recent Solar Energy UK and MCS contractor data.

The calculator returns material, labour, and disposal subtotals; total cost; cost per panel; cost per replaced watt; and the percentage of an equivalent new MCS install — so you can decide whether to patch or replace.

The formula

material   = panels × watts × pricePerW
labour     = panels × hoursPerPanel × rate + callout
disposal   = panels × disposalFee
total      = material + labour + disposal
perPanel   = total / panels
perW       = total / (panels × watts)
fullNew    = panels × watts × newSystemPerW
verdictPct = total / fullNew × 100

A worked example for 4 panels at 410 W with £0.42/W material, 1.1 hours labour each, £55/hour, £18 disposal, £180 van fee, and a £1.70/W new-system benchmark:

  • Material = 4 × 410 × 0.42 = £689
  • Labour = 4 × 1.1 × 55 + 180 = 242 + 180 = £422
  • Disposal = 4 × 18 = £72
  • Total = 689 + 422 + 72 = £1,183
  • Per panel = £295.75
  • Per replaced watt = 1,183 / 1,640 = £0.72/W
  • Full new equivalent = 1.64 kW × £1.70 = £2,788
  • Verdict = 1,183 / 2,788 = 42% — partial replacement clearly wins

That 42 percent figure means the partial route saves about three-fifths of what an MCS replacement install would cost for the same 1.64 kW slice. Cross above 70 percent and full system replacement becomes the better outcome.

UK-specific cost drivers

Material price per watt (tier-1 monocrystalline, distributor pricing into UK trade, Q1 2026):

Region£/W material
London + Home Counties£0.42 to £0.48
South West + South East£0.40 to £0.46
Midlands£0.38 to £0.44
North West + Yorkshire£0.38 to £0.42
North East£0.38 to £0.42
Wales£0.40 to £0.46
Scotland (Central Belt)£0.40 to £0.46
Scotland Highlands + Islands£0.46 to £0.55 (freight surcharge)

Labour rates (MCS-registered residential installer, blended van rate):

  • Central London: £80 to £100/h
  • Greater London + South East: £65 to £80/h
  • South West, Midlands, Yorkshire: £55 to £70/h
  • North East, North West, Wales: £50 to £62/h
  • Scottish Central Belt: £55 to £68/h
  • Highlands and Islands: £70 to £85/h (van plus ferry / overnight)

These figures track the most recent Checkatrade and MyBuilder solar repair quotes plus the Solar Energy UK installer cost survey. They include the full van burden, not just the engineer’s wage.

When the manufacturer warranty pays off

Three failures that almost always trigger a successful warranty claim:

  • Hot spots or microcracks visible in IR thermography — your installer’s drone IR scan shows a 25°C delta versus neighbouring cells. Manufacturer accepts and ships a replacement; you pay only labour.
  • Power below the linear warranty curve — measured with a clamp meter on the panel’s DC output at full sun. A 10-year-old panel measuring 85 percent of nameplate against a 0.5 percent/year linear curve (which would be 95 percent at year 10) has a clear claim.
  • Visible delamination, encapsulant browning, snail trails, or junction-box failure — these are explicit product warranty triggers in every UK tier-1 manufacturer’s terms.

What is not covered: hail damage (your home insurance), pigeon nesting damage (insurance with garden cover), and lightning strikes (insurance). For lightning specifically, claim through home insurance first — the deductible is typically lower than the labour cost of replacement.

For end-of-life accounting on the panels coming off the roof, see the solar panel recycling cost calculator. For dust and soiling that may not need full replacement, the solar panel cleaning cost calculator helps decide between wash and swap.

Reading the MCS replacement quote

A 4-panel replacement quote should break down roughly as:

  • Modules (panels + clips + new mid-clamps): 40 to 55 percent
  • Labour (engineer + roofer + commissioning): 30 to 40 percent
  • Disposal / WEEE recycling: 4 to 8 percent
  • Van / mobilisation: 10 to 18 percent
  • Building Control or DNO notification (only for capacity uplift): 0 to 5 percent

If labour exceeds 55 percent, either the system has access difficulties (third storey, steep slate roof, integrated in-roof system) or the installer is inflating the visit. Slate and clay tile add roughly 30 percent labour over composite shingle because each tile-replacement flashing must be lifted and re-bedded. Trapezoidal metal cladding is the fastest to swap. In-roof (BIPV) systems are the most expensive — count on £450 to £650 per panel because the roof membrane has to be cut and reflashed.

For DNO notification, a like-for-like or sub-3.68 kW system stays on G98 fast-track; uplifting beyond 3.68 kW per phase requires G99 prior approval which adds 6 to 10 weeks. See the solar permit cost calculator for current DNO fee ranges if you’re scoping a capacity increase rather than a like-for-like swap.

When to walk away from partial replacement

Run two scenarios in the calculator:

  1. Partial replacement at £0.42/W material and your installer’s labour rate.
  2. Full MCS-installed system at £1.70/W (or whatever the most recent EnergySage UK / Solar Together quote was).

If partial replacement comes in below 50 percent of the equivalent new install for the affected capacity, replace the panels. Between 50 and 70 percent, weigh the age of the rest of the system and the remaining warranty period. Above 70 percent, the full new-system route generally wins because of the fresh MCS warranty, modern higher-current modules, and a clean DNO notification on the new capacity.

For systems older than 15 years where the inverter is also near end-of-life, full replacement also re-establishes the 20-year linear warranty and qualifies the new install for current SEG export tariffs (Octopus Outgoing Fixed at 15p/kWh, EDF Export+ at 12p/kWh) — which a panel-only swap does not.

Sources

Frequently asked questions

How much does it cost to replace a solar panel in the UK?
A single replacement 410 W panel through an MCS installer runs about £190 to £320 fitted. Material is roughly £150 to £180 at £0.38 to £0.45 per watt wholesale, labour 1 hour at £55 to £75 (van rate, not just the engineer), and £15 to £25 disposal to a PV CYCLE UK partner. The first panel always carries the van fee (typically £150 to £200) — replacing 3 to 5 panels on one visit halves the per-panel cost.
Does the manufacturer warranty cover replacement panels?
Most tier-1 manufacturers (Q CELLS, REC, JA Solar, Trina) cover free replacement modules for 12 to 25 years on the product warranty plus a 25 to 30 year linear power warranty (output above 80 to 90 percent of nameplate). The warranty almost never covers labour or shipping — the MCS installer's removal and refit cost is yours, typically £200 to £400 per panel. Always log the failure with photos and a clamp-meter Voc/Isc reading before the panel comes off the roof.
Will replacing panels affect my MCS certificate and FIT or SEG payments?
Like-for-like or higher-wattage replacement does not invalidate the original MCS certificate so long as the installer is MCS-registered and they record the work on the existing MCS Installation Database entry. For historic Feed-in Tariff (FIT) systems, replacing more than half the original array can trigger a recommissioning by Ofgem — keep the system at the original DNO-notified rating to avoid affecting payments. SEG (Smart Export Guarantee) is uncapped, so wattage increases are fine but still need DNO notification under G98 or G99.
Should I replace one panel or upgrade the whole system?
If the original modules are still hitting 90 percent of nameplate and the system is under 12 years old, partial replacement is the right call. Beyond that, a 410 W modern module mismatches with an older 280 W string — the new panel is current-clipped by the weakest module in the string. Full system replacement is sensible when the original wattage is more than 25 percent below current panel ratings, when more than 30 percent of the modules have failed, or when the inverter has reached end-of-life (most string inverters last 10 to 12 years). Run the verdict figure below — anything above 70 percent of new-system cost means walk away from partial.
Where do old solar panels go in the UK?
Under the WEEE Directive (and UK retained law since 2021), solar PV modules are classified as electrical waste and must go through a registered PV CYCLE UK or licenced WEEE facility — not general waste. Recolight, ENVA, and Sims Lifecycle Services run UK-wide collection schemes. Most MCS installers pay a gate fee of £10 to £25 per panel and include it in your quote. Householders can also drop modules at any HWRC (Household Waste Recycling Centre) that accepts WEEE, but the installer should still handle disposal as part of the job.

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