13.23kW Residential Solar Installation with 27kWh Sigenergy Battery in Sutton, Surrey
The Opportunity: A High-Demand Sutton Home
This residential property in Sutton, Surrey — a short drive from Sol4r Energy's own head office — uses around 15,000 kWh of electricity a year, more than three times the UK household average. On an Octopus Flexible Economy 7 tariff, that meant high electricity bills, rising every year. The homeowner came to Sol4r Energy for a system big enough to make a real dent in that demand: solar generation sized for the household, and enough battery storage to carry it through the evening and night.
The property has a three-phase supply and three usable flat roofs, including the rear extension and a garden room. Rather than settle for flat-laid panels, Sol4r Energy mounted all 27 AIKO Neostar 490W panels on tilt racks at 20°, angling them towards the sun across all three roofs.
The property in Sutton — AIKO Neostar 490W panels on the flat roof of the rear extension, part of a 27-panel system installed by Sol4r Energy.
Sol4r Energy designed a 13.23 kWp system paired with 27.12 kWh of Sigenergy battery storage and a 12 kW three-phase SigenStor hybrid inverter. Using SAM (System Advisor Model) performance modelling, the system was engineered to offset 68% of the household's total electricity demand, deliver £4,188 in first-year savings, and pay for itself in just 4 years and 6 months. Net savings over 25 years are projected at £150,834.
Installation Video — Sutton, Surrey
Watch our team install the 13.23kW solar and battery system in Sutton.
Before & After: The Transformation
❌ Before Sol4r Energy
- 100% reliant on the grid for every unit of electricity
- 15,000 kWh consumed per year with zero on-site generation
- No battery storage — unable to shift energy to cheaper hours
- Fully exposed to rising energy prices — 7%+ annual increases
- Three flat roofs sitting unused
- No way to reduce the household's carbon footprint
✅ After Sol4r Energy
- 68% energy offset — generating 10,189 kWh per year on-site
- 27.12 kWh Sigenergy battery covering evenings and overnight usage
- Household in credit on its electricity account from April to September
- £4,188 saved in year one
- 3 tonnes of CO₂ eliminated every year
- System pays for itself in 4 years 6 months — then generates pure savings
Installation Photos — Sutton, Surrey
27 × AIKO Neostar 490W solar panels on tilt racks across three flat roofs, Sigenergy SigenStor EC 12.0TP three-phase hybrid inverter, 3 × SigenStor BAT 10.0 battery modules (27.12 kWh), Sigen three-phase power sensor & birds protection — all installed by Sol4r Energy's in-house team at a residential property in Sutton, Surrey.
Project Overview — Residential Solar, Sutton, Surrey
| Detail | Information |
|---|---|
| Location | Residential property in Sutton, Surrey |
| Property type | Residential property · three-phase supply |
| Roof configuration | Three flat roofs (rear extension, garden room and a further flat section) — all 27 panels on tilt racks at 20° |
| Annual consumption | 15,000 kWh |
| Tariff recommendation | Switch from Octopus Flexible Economy 7 to Octopus Intelligent — Day 31p (5am–11pm), Night 7p (11pm–5am) |
| Export tariff (SEG) | Smart Export Guarantee — 15p/kWh all day |
| Performance calculator | System Advisor Model SAM 2025.4.16 |
| MCS certified | Yes — all systems registered, certificates issued on completion |
Technical Specifications — Solar & Battery
Every component was chosen for high output, long life and intelligent energy management. The Sigenergy ecosystem — inverter, batteries and power sensor — works as one connected three-phase system, managed from a single app:
| Component | Product | Specification |
|---|---|---|
| Solar Panels | 27 × AIKO 490W | Neostar 3P+54 dual-glass · AIKO-A490-MCE54Dw · back-contact cells · 13.23 kWp total · 30yr product & 30yr performance warranty |
| Hybrid Inverter | 1 × SigenStor EC 12.0TP | 12 kW three-phase hybrid · EMS built-in · 10yr warranty |
| Battery Storage | 3 × SigenStor BAT 10.0 | 27.12 kWh total · LiFePO4 · 10,000 cycles · 100% depth of discharge · 10yr warranty |
| Power Sensor | 1 × Sigenergy TP-CT120-DH | Three-phase external CT meter · real-time import/export monitoring for the EMS |
| Mounting | Tilt racks (27 panels) | 20° tilt on all three flat roofs |
| Additional | Birds protection | Full birds protection mesh around the array |
Three Flat Roofs, One Tilted Array
The property offered three separate flat-roof areas facing different directions. Sol4r Energy put tilt racks on all three, spreading the 27 panels across three groups so the system generates from late morning right through to the evening:
| Roof Area | Orientation | Panels | Configuration |
|---|---|---|---|
| Group 1 | West-southwest · 20° tilt | 14 panels (6.86 kWp) | Largest array — captures strong afternoon and early-evening sun |
| Group 2 | West-southwest · 20° tilt | 8 panels (3.92 kWp) | Second flat roof with the same aspect — adds to the afternoon peak |
| Group 3 | South · 20° tilt | 5 panels (2.45 kWp) | Near-due-south — strongest midday generation |
With 22 of the 27 panels facing west-southwest, generation leans towards the afternoon and early evening — exactly when a busy household's demand starts to climb. The south-facing group fills in the midday peak. Whatever the panels produce beyond the home's immediate needs goes into the 27.12 kWh Sigenergy battery, ready for the evening. Mounting on tilt racks also keeps rainwater running off the panels, which helps them stay cleaner than flat-laid modules.
Energy Performance & Self-Consumption
| Performance Metric | Result |
|---|---|
| Total installed capacity | 13.23 kWp |
| Annual solar generation | 10,189 kWh |
| Annual household consumption | 15,000 kWh |
| Annual consumption offset | 68% — the system produces over two-thirds of the household's demand |
| kWh/kWp yield | 882.3 kWh/kWp |
| Shade factor | 0.873 |
| Self-consumption — solar only | 4,615 kWh (30.8% self-sufficiency) |
| Self-consumption — solar + battery | 5,186 kWh (35.0% self-sufficiency) |
| Total energy discharged from battery per year | 19,798 kWh |
| Usable battery capacity | 27.12 kWh |
With 15,000 kWh of annual demand and 10,189 kWh of solar generation, the system offsets 68% of total household electricity consumption. The 27.12 kWh Sigenergy battery lifts self-sufficiency from 30.8% (solar only) to 35% with storage and, more importantly, lets the household use the 24p/kWh gap between Octopus Intelligent's night rate (7p) and day rate (31p). With 19,798 kWh of battery throughput a year, the battery cycles roughly twice a day: charging cheaply overnight and from surplus solar, then powering the home when grid electricity is most expensive. For homeowners in Sutton, Belmont, Cheam, Carshalton, Banstead and Ewell, and across Surrey and South London, this shows what a well-sized system can do for a high-consumption home.
Monthly Savings Breakdown — Year 1
Every month of the year, this system delivers substantial bill reductions — saving between £264 and £427 per month, with the household in credit from April to September:
| Month | Solar Gen | Imported | Exported | Export Credit | Saving |
|---|---|---|---|---|---|
| January | 189 kWh | 1,407 kWh | 0 kWh | £0 | £281 |
| February | 321 kWh | 1,224 kWh | 0 kWh | £0 | £298 |
| March | 665 kWh | 996 kWh | 118 kWh | £18 | £368 |
| April | 1,123 kWh | 716 kWh | 544 kWh | £82 | £394 |
| May | 1,536 kWh | 560 kWh | 952 kWh | £143 | £427 |
| June | 1,471 kWh | 521 kWh | 909 kWh | £136 | £407 |
| July | 1,548 kWh | 491 kWh | 994 kWh | £149 | £412 |
| August | 1,381 kWh | 522 kWh | 871 kWh | £131 | £385 |
| September | 937 kWh | 648 kWh | 453 kWh | £68 | £343 |
| October | 567 kWh | 883 kWh | 162 kWh | £24 | £315 |
| November | 292 kWh | 1,181 kWh | 0 kWh | £0 | £293 |
| December | 158 kWh | 1,424 kWh | 0 kWh | £0 | £264 |
| ANNUAL TOTAL | 10,189 kWh | 10,573 kWh | 5,003 kWh | £751 | £4,188 saved |
Projections assume a 7% annual energy price increase. Utility savings based on a switch from Octopus Flexible Economy 7 (London) to Octopus Intelligent. From April through September the household runs in net credit, earning more from exports than it pays for imports. In winter, the 27 kWh battery charging at 7p overnight and discharging at 31p during the day keeps monthly savings above £260 even when solar output is low.
Monthly Energy Cost
Before solar vs. after solar — the visual tells the story
After solar, the household's electricity bill is cut by around 90% over the year. From April to September the account runs in credit, and even in the darkest winter months bills are cut by more than half.
Financial Returns — Residential Solar Investment
With energy prices projected to rise by 7% a year, this system pays for itself in four and a half years, then delivers over £150,000 in net savings across the rest of its life. By 2035, annual savings are projected to reach £6,668; by 2050, £10,033 a year. Even discounted at 6.75% a year, the system has a net present value of £53,546 and a discounted payback of 5 years 5 months. That is a 736% total return on investment and a 25% annual rate of return. With 0% VAT on domestic solar, the quoted price covered the full installation with no hidden costs. For homeowners across Sutton, Belmont, Cheam, Carshalton, Wallington, Banstead and Ewell, and the wider Surrey and South London area, solar with battery storage is one of the most effective financial decisions you can make for your home. Book a free property survey to find out what solar could save you.
Battery Storage: The Sigenergy Advantage
27 kWh of storage on a three-phase system = power for the whole evening
For a household using 15,000 kWh a year, generation alone isn't enough: most of that demand falls in the evening and overnight. Three SigenStor battery modules on a 12 kW three-phase inverter give the home enough stored energy to cover it.
Intelligent Tariff Arbitrage
Charges at 7p/kWh overnight on Octopus Intelligent, then powers the home instead of 31p/kWh daytime grid electricity. Across 19,798 kWh of annual battery throughput, that 24p/kWh difference adds up fast.
Three-Phase Power
The SigenStor EC 12.0TP balances generation and battery output across all three phases of the home's supply, with up to 12 kW of inverter power available for heavy household loads.
35% Grid Independence
Solar alone gives 30.8% self-sufficiency. The 27 kWh battery lifts this to 35%, moving stored solar and cheap overnight electricity into the hours when it's needed most.
10,000-Cycle LiFePO4
LiFePO4 cells rated for 10,000 charge cycles at 100% depth of discharge. Even cycling around twice a day, that's well beyond the 10-year battery warranty.
One Integrated System
Inverter, batteries and the three-phase power sensor all talk to Sigenergy's built-in Energy Management System, with 20 years of online monitoring and performance support from Sol4r Energy.
Compounding Savings
With energy costs rising 7% a year, savings grow every year. By 2035, this system saves £6,668 a year; by 2050, £10,033 — totalling £150,834 in net savings over 25 years.
Environmental Impact
At 3 tonnes of CO₂ eliminated per year, this installation makes a real, measurable environmental contribution. Over the system's lifetime, that's the equivalent of planting 498 trees, avoiding 55 long-haul flights, or taking a car off the road for more than 77,000 kilometres. Sol4r Energy installs residential solar systems across Sutton, Belmont, Cheam, Carshalton, Wallington, Banstead, Ewell, Surrey and nationwide.
Why This Homeowner Chose Sol4r Energy
Certifications & Warranties Included
All certifications issued on completion. Sol4r Energy is HIES-registered, NAPIT-approved, and TrustMark-endorsed — the highest level of consumer protection for solar installations in the UK. 0% VAT applies to all domestic solar installations.
Solar PV Finance
Finance option available through Phoenix Financial Consultants Limited.
All finance applications are subject to status and approval by Phoenix Financial Consultants Limited. Sol4r Energy Ltd is an Introducer Appointed Representative (Financial Services Register No. 1005252) of Phoenix Financial Consultants Limited (FRN: 539195), which is authorised and regulated by the Financial Conduct Authority. Phoenix Financial Consultants Limited is a credit broker, not a lender.
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