Solar explained to clever people by people who are not trying to be clever

Solar Panels in RM13 (Havering)

See if solar pays off for you in Havering — price, savings and payback in under a minute (official UK data).

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
12.1 years
After this, it's pure profit
Upfront Cost
£10,173
What you pay to get started
Annual Benefit
£843
What you save every year
Profit Over 25 Years
£10,910
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

Read the full story

A typical roof here lands around 5.0 kW, with most eligible homes comfortably fitting within 3–6 kW. Each kilowatt of panels produces roughly 1015 kWh per year on a south-facing roof. We value self-used electricity at 26.5p and exported surplus at a baseline 10p via SEG. Use the calculator above for your exact tariff.

Unit rate
26.5p/kWh
Standing charge
48.2p/day
Sunshine yield (south)
1015 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: £843, Upfront: £10,173, Break-even: 12.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2031 kWh 812 kWh 1218 kWh £215 £122 £337 £4,069 12.1 yrs £2,677
3 kW 3046 kWh 1218 kWh 1828 kWh £323 £183 £506 £6,104 12.1 yrs £4,016
4 kW 4061 kWh 1624 kWh 2437 kWh £431 £244 £675 £8,138 12.1 yrs £5,355
5 kW 5076 kWh 2031 kWh 3046 kWh £539 £305 £843 £10,173 12.1 yrs £6,693
6 kW 6092 kWh 2437 kWh 3655 kWh £646 £366 £1,012 £12,207 12.1 yrs £8,032
7 kW 7107 kWh 2843 kWh 4264 kWh £754 £426 £1,181 £14,242 12.1 yrs £9,371
8 kW 8122 kWh 3249 kWh 4873 kWh £862 £487 £1,349 £16,276 12.1 yrs £10,710

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: £1,011, Upfront: £12,273, Break-even: 12.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2031 kWh 1218 kWh 812 kWh £323 £81 £404 £6,169 15.3 yrs £1,920
3 kW 3046 kWh 1828 kWh 1218 kWh £485 £122 £607 £8,204 13.5 yrs £3,930
4 kW 4061 kWh 2437 kWh 1624 kWh £646 £162 £809 £10,238 12.7 yrs £5,940
5 kW 5076 kWh 3046 kWh 2031 kWh £808 £203 £1,011 £12,273 12.1 yrs £7,950
6 kW 6092 kWh 3655 kWh 2437 kWh £970 £244 £1,213 £14,307 11.8 yrs £9,960
7 kW 7107 kWh 4264 kWh 2843 kWh £1,131 £284 £1,416 £16,342 11.5 yrs £11,970
8 kW 8122 kWh 4873 kWh 3249 kWh £1,293 £325 £1,618 £18,376 11.4 yrs £13,980

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: £1,095, Upfront: £13,673, Break-even: 12.5 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2031 kWh 1421 kWh 609 kWh £377 £61 £438 £7,569 17.3 yrs £1,191
3 kW 3046 kWh 2132 kWh 914 kWh £566 £91 £657 £9,604 14.6 yrs £3,537
4 kW 4061 kWh 2843 kWh 1218 kWh £754 £122 £876 £11,638 13.3 yrs £5,883
5 kW 5076 kWh 3554 kWh 1523 kWh £943 £152 £1,095 £13,673 12.5 yrs £8,228
6 kW 6092 kWh 4264 kWh 1828 kWh £1,131 £183 £1,314 £15,707 12.0 yrs £10,574
7 kW 7107 kWh 4975 kWh 2132 kWh £1,320 £213 £1,533 £17,742 11.6 yrs £12,920
8 kW 8122 kWh 5686 kWh 2437 kWh £1,508 £244 £1,752 £19,776 11.3 yrs £15,265

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: £1,120, Upfront: £15,423, Break-even: 13.8 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2031 kWh 1482 kWh 548 kWh £393 £55 £448 £9,319 20.8 yrs £-357
3 kW 3046 kWh 2223 kWh 822 kWh £590 £82 £672 £11,354 16.9 yrs £2,089
4 kW 4061 kWh 2965 kWh 1097 kWh £787 £110 £896 £13,388 14.9 yrs £4,535
5 kW 5076 kWh 3706 kWh 1371 kWh £983 £137 £1,120 £15,423 13.8 yrs £6,982
6 kW 6092 kWh 4447 kWh 1645 kWh £1,180 £164 £1,344 £17,457 13.0 yrs £9,428
7 kW 7107 kWh 5188 kWh 1919 kWh £1,376 £192 £1,568 £19,492 12.4 yrs £11,874
8 kW 8122 kWh 5929 kWh 2193 kWh £1,573 £219 £1,792 £21,526 12.0 yrs £14,321

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: £1,137, Upfront: £17,173, Break-even: 15.1 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2031 kWh 1523 kWh 508 kWh £404 £51 £455 £11,069 24.3 yrs £-1,973
3 kW 3046 kWh 2284 kWh 761 kWh £606 £76 £682 £13,104 19.2 yrs £540
4 kW 4061 kWh 3046 kWh 1015 kWh £808 £102 £910 £15,138 16.6 yrs £3,054
5 kW 5076 kWh 3807 kWh 1269 kWh £1,010 £127 £1,137 £17,173 15.1 yrs £5,567
6 kW 6092 kWh 4569 kWh 1523 kWh £1,212 £152 £1,364 £19,207 14.1 yrs £8,081
7 kW 7107 kWh 5330 kWh 1777 kWh £1,414 £178 £1,592 £21,242 13.3 yrs £10,594
8 kW 8122 kWh 6092 kWh 2031 kWh £1,616 £203 £1,819 £23,276 12.8 yrs £13,108

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: £1,154, Upfront: £19,623, Break-even: 17.0 yrs
System Annual output Self-use Exported Bill saving Export income Annual benefit Upfront cost Break-even 20-year net
2 kW 2031 kWh 1564 kWh 467 kWh £415 £47 £462 £13,519 29.3 yrs £-4,289
3 kW 3046 kWh 2345 kWh 701 kWh £622 £70 £692 £15,554 22.5 yrs £-1,708
4 kW 4061 kWh 3127 kWh 934 kWh £830 £93 £923 £17,588 19.1 yrs £872
5 kW 5076 kWh 3909 kWh 1168 kWh £1,037 £117 £1,154 £19,623 17.0 yrs £3,453
6 kW 6092 kWh 4691 kWh 1401 kWh £1,244 £140 £1,385 £21,657 15.6 yrs £6,034
7 kW 7107 kWh 5472 kWh 1635 kWh £1,452 £163 £1,615 £23,692 14.7 yrs £8,614
8 kW 8122 kWh 6254 kWh 1868 kWh £1,659 £187 £1,846 £25,726 13.9 yrs £11,195

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.

Your Area at a Glance

Your Electricity Rate
26.53p/kWh
Daily Fixed Charge
48.25p/day
Local Sunshine
1015kWh/kW
A 1 kW system generates ~1015 kWh per year. A typical home uses ~2,700 kWh per year.
Typical System Size
5.0kW
For houses & bungalows in this area

Local Property Data

Property Types

Houses: 54% • Flats: 35% • Bungalows: 8% Based on 8,660 properties

Coverage

Havering (100%)

Areas Covered

Rainham & Wennington, South Hornchurch, Beam Park, Elm Park

Data Sources & Assumptions

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

Electricity rates: Ofgem price cap, Q4 2025

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.