£8 Per Month Energy Bills With Solar Panels
A 4.2kW solar and 10.5kWh battery system reduces monthly bills to just £8, with £180 credit balance.
Hampshire • Residential
Annual Savings
£1,400
Bill Reduction
70%
CO₂ Saved
1.3t
Payback Period
5.5y
The savings and payback figures in this case study are this customer's actual results. Your own savings will be specific to your installation and depend on your energy generation and usage, and on energy costs at the time of installation.
" We only paid £64 total over eight months. With the credit balance, the system is essentially paying for itself even faster than promised. "
Property Details
- Property Type
- Residential
- Location
- Hampshire
Services Installed
System Specifications
| Solar Capacity | 4.2 kW |
| Battery Storage | 10.5 kWh |
| Number of Panels | 14 panels |
| Inverter Model | SolarEdge SE4000H |
| Annual Generation | ~4000 kWh |
The Setup
This 4-bed detached home received a premium solar and battery installation:
- 4.2kW solar array with 14 premium panels
- 10.5kWh battery storage system
- SolarEdge SE4000H inverter with module-level monitoring
- Annual generation capacity: 4,000 kWh
- Total amount paid: £64
- Account credit balance: £180 remaining
- Monthly average cost: £8 (mostly standing charges)
- System is simultaneously generating and storing energy while paying for itself
- Grid electricity: £486.29
- Gas: £306.45
- Total consumed: £792.74
- Solar exports: 3,196 kWh at 15p per kWh = £479.34
- This nearly offsets the grid electricity consumed
- Standing charges: £280 for 8 months (£35/month typical)
- Store excess generation from midday hours
- Use stored energy in the evening peak demand period
- Minimize grid imports when they're most expensive
- Maximize the value of every kWh generated by the panels
- Total 25-year savings: £35,000+
- Payback period: approximately 5.5 years
- Free generation years: 19.5+ years
The Remarkable Results
From April 2025 to January 2026 (8 months), the household situation is:
Financial Breakdown
Here's exactly how the numbers work over the 8-month period:
Energy consumed:
Energy exported:
Fixed costs:
Why Battery Storage Is Critical
The 10.5kWh battery system is crucial to these results. It allows the household to:
Without battery storage, much of the midday generation would be exported at 15p per kWh rather than kept for evening use.
25-Year Projection
With such low ongoing costs and export earnings exceeding grid consumption:
Financial Summary
Previous Annual Bill
£2,000
Reduction
70%
New Annual Bill
£600
Annual Savings
£1,400
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