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Solar panel cost in Spelthorne (TW17)

See realistic solar installation costs, savings and payback for TW17 (Spelthorne) in under a minute using official UK data. Start with the calculator, then get a no-obligation quote from an MCS-certified installer. You can also ask the SolarByPostcode assistant to sanity-check your roof, bills and plans.

Solar Calculator

Change the settings below to see how costs and savings work for your situation.

System Size

Roof Direction

Battery Storage

Export Value

Your Numbers

Break-even
11.8 years
After this, it's pure profit
Upfront Cost
£12,207
What you pay to get started
Annual Benefit
£1,035
What you save every year
Profit Over 25 Years
£13,666
After paying itself off, you're this much ahead

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How we calculate this

Solar generation: Based on typical south-facing roof at 35° angle. We account for weather, dirt, and system losses (14%).

How much you'll use directly:

  • Without battery: You'll use about 40% of what you generate. The rest gets sold back to the grid.
  • With 5 kWh battery: You'll use about 70% (battery stores extra for evening use).
  • With 10 kWh battery: You'll use about 75% (more storage means less exported).
  • Panel-only payback: Bigger systems don’t shorten payback—cost and savings rise together per kW.
  • Battery & payback: Batteries raise self-use and cut bills, but added hardware cost often lengthens break-even at typical UK rates.
  • When a battery can still make sense:
    • Evening-heavy usage patterns
    • Time-of-use tariffs / cheap night rates
    • Low export rate vs. high unit rate
    • Heat pump or EV charging synergy
    • Optional backup/resilience (system-dependent)
    • Lower evening-hour CO₂ vs. grid

Costs: Battery prices are typically £700 per kWh. Export tariffs vary by supplier (usually 5–15p per kWh).

Grid connection: Systems up to about 3.7 kW typically need just a notification (G98). Larger systems may need permission (G99).

These are typical values based on average usage patterns. Your actual results will vary based on your roof, shading, and how you use electricity.

Your area in context

In South East, the current unit rate is 28.27p/kWh with a 48.66p/day standing charge. Your postcode’s south-facing sunshine yield is 997 kWh/kW — 32 below the regional median (1029).

Read the full story

A typical roof here lands around 6.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 997 kWh per year on a south-facing roof. We value self-used electricity at 28.3p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
28.3p/kWh
Standing charge
48.7p/day
Sunshine yield (south)
997 kWh/kW
Export price (baseline)
10p/kWh

Browse the scenarios below. Each battery size has its own expand — open the one that matches your plan (or just explore). For each system size (2–8 kW) we show annual output, how much you use directly, what gets exported, annual benefit, upfront cost, break-even, and a 20-year net. Negative numbers are possible — that’s the honest trade-off when adding more battery than your usage profile justifies.

No battery 5 kW example → Annual benefit: £862, Upfront: £10,173, Break-even: 11.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1993 kWh 797 kWh 1196 kWh £225 £120 £345 £4,069 11.8 yrs £2,831
3 kW 2990 kWh 1196 kWh 1794 kWh £338 £179 £517 £6,104 11.8 yrs £4,246
4 kW 3986 kWh 1595 kWh 2392 kWh £451 £239 £690 £8,138 11.8 yrs £5,661
5 kW 4983 kWh 1993 kWh 2990 kWh £563 £299 £862 £10,173 11.8 yrs £7,076
6 kW 5979 kWh 2392 kWh 3588 kWh £676 £359 £1,035 £12,207 11.8 yrs £8,492
7 kW 6976 kWh 2790 kWh 4186 kWh £789 £419 £1,207 £14,242 11.8 yrs £9,907
8 kW 7973 kWh 3189 kWh 4784 kWh £902 £478 £1,380 £16,276 11.8 yrs £11,322

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

3 kWh battery 5 kW example → Annual benefit: £1,045, Upfront: £12,273, Break-even: 11.7 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1993 kWh 1196 kWh 797 kWh £338 £80 £418 £6,169 14.8 yrs £2,187
3 kW 2990 kWh 1794 kWh 1196 kWh £507 £120 £627 £8,204 13.1 yrs £4,331
4 kW 3986 kWh 2392 kWh 1595 kWh £676 £159 £836 £10,238 12.3 yrs £6,474
5 kW 4983 kWh 2990 kWh 1993 kWh £845 £199 £1,045 £12,273 11.7 yrs £8,618
6 kW 5979 kWh 3588 kWh 2392 kWh £1,014 £239 £1,253 £14,307 11.4 yrs £10,761
7 kW 6976 kWh 4186 kWh 2790 kWh £1,183 £279 £1,462 £16,342 11.2 yrs £12,905
8 kW 7973 kWh 4784 kWh 3189 kWh £1,352 £319 £1,671 £18,376 11.0 yrs £15,048

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

5 kWh battery 5 kW example → Annual benefit: £1,136, Upfront: £13,673, Break-even: 12.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1993 kWh 1395 kWh 598 kWh £394 £60 £454 £7,569 16.7 yrs £1,515
3 kW 2990 kWh 2093 kWh 897 kWh £592 £90 £681 £9,604 14.1 yrs £4,023
4 kW 3986 kWh 2790 kWh 1196 kWh £789 £120 £908 £11,638 12.8 yrs £6,531
5 kW 4983 kWh 3488 kWh 1495 kWh £986 £149 £1,136 £13,673 12.0 yrs £9,039
6 kW 5979 kWh 4186 kWh 1794 kWh £1,183 £179 £1,363 £15,707 11.5 yrs £11,546
7 kW 6976 kWh 4883 kWh 2093 kWh £1,380 £209 £1,590 £17,742 11.2 yrs £14,054
8 kW 7973 kWh 5581 kWh 2392 kWh £1,578 £239 £1,817 £19,776 10.9 yrs £16,562

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

7.5 kWh battery 5 kW example → Annual benefit: £1,163, Upfront: £15,423, Break-even: 13.3 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1993 kWh 1455 kWh 538 kWh £411 £54 £465 £9,319 20.0 yrs £-16
3 kW 2990 kWh 2183 kWh 807 kWh £617 £81 £698 £11,354 16.3 yrs £2,601
4 kW 3986 kWh 2910 kWh 1076 kWh £823 £108 £930 £13,388 14.4 yrs £5,218
5 kW 4983 kWh 3638 kWh 1345 kWh £1,028 £135 £1,163 £15,423 13.3 yrs £7,835
6 kW 5979 kWh 4365 kWh 1614 kWh £1,234 £161 £1,395 £17,457 12.5 yrs £10,452
7 kW 6976 kWh 5093 kWh 1884 kWh £1,440 £188 £1,628 £19,492 12.0 yrs £13,069
8 kW 7973 kWh 5820 kWh 2153 kWh £1,645 £215 £1,861 £21,526 11.6 yrs £15,686

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

10 kWh battery 5 kW example → Annual benefit: £1,181, Upfront: £17,173, Break-even: 14.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1993 kWh 1495 kWh 498 kWh £423 £50 £472 £11,069 23.4 yrs £-1,620
3 kW 2990 kWh 2242 kWh 747 kWh £634 £75 £709 £13,104 18.5 yrs £1,069
4 kW 3986 kWh 2990 kWh 997 kWh £845 £100 £945 £15,138 16.0 yrs £3,759
5 kW 4983 kWh 3737 kWh 1246 kWh £1,056 £125 £1,181 £17,173 14.5 yrs £6,449
6 kW 5979 kWh 4485 kWh 1495 kWh £1,268 £149 £1,417 £19,207 13.6 yrs £9,139
7 kW 6976 kWh 5232 kWh 1744 kWh £1,479 £174 £1,654 £21,242 12.8 yrs £11,828
8 kW 7973 kWh 5979 kWh 1993 kWh £1,690 £199 £1,890 £23,276 12.3 yrs £14,518

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

13.5 kWh battery 5 kW example → Annual benefit: £1,199, Upfront: £19,623, Break-even: 16.4 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 1993 kWh 1535 kWh 458 kWh £434 £46 £480 £13,519 28.2 yrs £-3,925
3 kW 2990 kWh 2302 kWh 688 kWh £651 £69 £720 £15,554 21.6 yrs £-1,162
4 kW 3986 kWh 3069 kWh 917 kWh £868 £92 £959 £17,588 18.3 yrs £1,600
5 kW 4983 kWh 3837 kWh 1146 kWh £1,085 £115 £1,199 £19,623 16.4 yrs £4,363
6 kW 5979 kWh 4604 kWh 1375 kWh £1,302 £138 £1,439 £21,657 15.0 yrs £7,126
7 kW 6976 kWh 5372 kWh 1604 kWh £1,519 £160 £1,679 £23,692 14.1 yrs £9,888
8 kW 7973 kWh 6139 kWh 1834 kWh £1,735 £183 £1,919 £25,726 13.4 yrs £12,651

Assumptions: south-facing, sensible tilt; self-use shares from site rules; export at 10p baseline. Costs: panels £/kW = 2,035, battery £/kWh = 700.

Figures are illustrative and use the same method as the calculator above. For exact results, adjust your roof direction, tariff, and usage in the calculator.

Insights for TW17

Figures below are tailored to TW17 — click through for full league tables.

Big-Roof Britain Rank #814 of 2182
5.2 kWp (UK avg 5.1 kWp)
~11 panels (≈430 W)
Solar Payback Index Rank #727 of 2997
11.8 years (UK avg 12.6 years)
~£1,035 /yr • £12,207 upfront
Standing-Charge Drag Rank #340 of 2997
17.2% (UK avg 24.6%) drag on savings
£178 fixed • ~£1,035 /yr value
Aspect Penalty View ranking →
East −21.3% West −19.5%
Typical output loss versus a south-facing roof (lower is better)

Your Area at a Glance

Your Electricity Rate
28.27p/kWh
Daily Fixed Charge
48.66p/day
Local Sunshine
997kWh/kW
A 1 kW system generates ~997 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
6.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 56% • Flats: 23% • Bungalows: 14% Based on 3,722 properties

Coverage

Spelthorne (99%)|Elmbridge (1%)

Areas Covered

Shepperton Town, Laleham and Shepperton Green, Halliford and Sunbury West, Walton Central, Weybridge Riverside

Data Sources & Assumptions

Solar yield: PVGIS (EU Joint Research Centre), January 2025 data

Electricity rates: Ofgem price cap, Q1 2026

Installation costs: MCS certified installer data, March 2025

Property data: EPC open data (Open Government Licence), aggregated

All estimates are typical values. Actual results vary based on your specific situation, roof characteristics, and usage patterns.

Compare nearby areas

Nearby in South East

KT13 (Elmbridge)
≈2.6 km away
Local sunshine: ~996 kWh/kWp · -0% vs TW17
KT12 (Elmbridge)
≈3.4 km away
Local sunshine: ~996 kWh/kWp · -0% vs TW17
KT16 (Runnymede)
≈4.1 km away
Local sunshine: ~997 kWh/kWp · -0% vs TW17
KT15 (Runnymede)
≈4.1 km away
Local sunshine: ~997 kWh/kWp · +0% vs TW17
KT8 (Elmbridge)
≈5.5 km away
Local sunshine: ~998 kWh/kWp · +0% vs TW17
TW12 (Richmond upon Thames)
≈6.1 km away
Local sunshine: ~1,000 kWh/kWp · +0% vs TW17

Similar sunshine across the UK

EX16 (Mid Devon)
~997 kWh/kWp · -0% vs TW17
GU25 (Runnymede)
~997 kWh/kWp · -0% vs TW17
SE20 (Bromley)
~997 kWh/kWp · -0% vs TW17