When Mark and Claire Johnson first considered solar panels for their 3-bedroom semi-detached home in Crosby, Liverpool, they were sceptical. “We thought solar wouldn’t work well this far north,” admits Mark. “But after speaking with Enviro-Energy and seeing the numbers, we decided to go for it. It’s been the best home improvement decision we’ve ever made.” For a detailed breakdown of the financial case, see our guide to solar ROI and the 7-year payback period.
Project Overview
4kW
System Size
10
Solar Panels
£1,200
Annual Saving
6.5 yrs
Payback Period
The Challenge
The Johnsons were spending approximately £2,400 per year on electricity and gas. With two children, a home office, and an electric vehicle on the way, they knew their energy costs were only going to increase. Their 1990s-built semi had an EPC rating of D, and they wanted to make meaningful improvements. They also explored other ways to reduce their energy bills before settling on solar as their primary investment.
“Our electricity bill alone was £140 a month,” says Claire. “With the kids growing up and using more devices, and Mark working from home three days a week, we were using a lot of power during the day when rates are highest.”
The Johnson Household
The Solution
After a thorough home assessment, Enviro-Energy recommended a 4kW solar PV system with 5.2kWh battery storage. The south-facing roof was ideal for solar generation, and the battery would allow the family to store excess daytime energy for use in the evenings.
System Specification
| Component | Details |
|---|---|
| Solar Panels | 10 x 400W monocrystalline panels (all-black design) |
| Inverter | GivEnergy 3.6kW hybrid inverter |
| Battery Storage | GivEnergy 5.2kWh lithium-ion battery |
| Monitoring | GivEnergy app with real-time generation and consumption data |
| Warranty | 25-year panel warranty, 12-year inverter and battery warranty |
The Installation Process
The entire installation was completed in just two days. Day one focused on the roof-mounted panels and electrical wiring, while day two covered the inverter, battery installation, and system commissioning.
Day 1: Panel Installation
Scaffolding erected, roof mounting system fitted, 10 panels installed and wired. All work completed by 4pm with full safety protocols observed.
Day 2: Battery & Commissioning
Hybrid inverter and battery installed in the garage. System tested, commissioned, and connected to the monitoring app. Full handover and walkthrough with the family.
“The Enviro-Energy team were brilliant. They arrived on time, kept everything tidy, and explained exactly what they were doing at every stage. We barely noticed they were here.” — Mark Johnson
The Results: 12 Months On
After a full year of operation, the results have exceeded the Johnsons’ expectations. Here’s a complete breakdown of their solar PV performance and financial savings:
| Metric | Before Solar | After Solar | Difference |
|---|---|---|---|
| Annual Electricity Bill | £1,680 | £620 | -£1,060 |
| SEG Export Income | £0 | £140 | +£140 |
| Total Annual Saving | £1,200 | ||
| Solar Generation | 3,850 kWh per year | ||
| Self-Consumption Rate | 72% (with battery) | ||
| CO2 Reduction | 0.89 tonnes per year | ||
Financial Breakdown
Investment
- Solar PV System (4kW)£5,800
- Battery Storage (5.2kWh)£2,400
- Total Investment£8,200
Returns
- Annual Bill Savings£1,060
- Annual SEG Income£140
- Total Annual Return£1,200
- Payback Period6.8 years
Seasonal Performance
One of the Johnsons’ initial concerns was whether solar would generate enough energy during the darker winter months. While generation is naturally lower in winter, the system still makes a meaningful contribution year-round:
| Season | Generation | Self-Use | Exported | Saving |
|---|---|---|---|---|
| Spring (Mar–May) | 1,050 kWh | 780 kWh | 270 kWh | £320 |
| Summer (Jun–Aug) | 1,400 kWh | 900 kWh | 500 kWh | £410 |
| Autumn (Sep–Nov) | 850 kWh | 650 kWh | 200 kWh | £280 |
| Winter (Dec–Feb) | 550 kWh | 450 kWh | 100 kWh | £190 |
“Even in December and January, we’re generating enough to cover our daytime usage on most days. The battery is a game-changer — it stores the midday surplus and powers us through the evening. Our electricity bill in July was just £12!” — Claire Johnson
Impact on Property Value
Beyond the immediate bill savings, the solar installation has improved the Johnsons’ EPC rating from D to B, which research suggests adds approximately £8,000–£12,000 to the property’s market value. With the UK government’s push towards net zero, energy-efficient homes are increasingly attractive to buyers. Combining solar with free insulation through ECO4 can push your EPC rating even higher. Homeowners considering a full low-carbon heating system should also explore the 2025 heat pump grants available through the Boiler Upgrade Scheme.
EPC Before
D
EPC After
B
The Verdict
Twelve months on, the Johnsons have no regrets. Their £8,200 investment is on track to pay for itself in under 7 years, after which they’ll enjoy free electricity for the remaining 18+ years of the system’s lifespan. They’ve also reduced their carbon footprint by nearly a tonne of CO2 per year.
“If you’re on the fence about solar, just do it. The technology works, the savings are real, and Enviro-Energy made the whole process completely painless. We only wish we’d done it sooner.” — Mark & Claire Johnson
Could Solar Work for Your Home?
Every home is different, but our team can assess your property and provide a detailed savings estimate — completely free and with no obligation. Join hundreds of Liverpool homeowners already saving with solar PV from Enviro-Energy.