Solar Panel Savings Calculator
Calculate the cost, savings, and payback period for installing solar panels on your roof. Compare different system sizes.
South-facing is optimal
30 degrees is ideal for UK
Typical domestic system
Current cap rate: 24.5p
SEG rates: typically 12-20p
For reference only
Annual Generation
5500
kWh/year
Annual Benefit
£1060.13
savings + exports
System Cost
£10000.00
before grants
Payback Period
4.7
years
Annual Generation
Performance factor: 100%
Based on direction and angle
Annual Income
Investment & Payback
System Installation Cost
£10000.00
Potential Grant/Loan
£5000.00
Net Cost
£5000.00
Payback: 4.7 years
25-Year Cumulative Return
After 25 years, your solar system will have saved you approximately £26503.13
Solar Panel Benefits
- Annual savings of £1060.13 from day one
- Generate 5.5 MWh clean electricity per year
- Payback in 4.7 years
- 25-year lifespan with minimal maintenance
- Export excess power to grid via Smart Export Guarantee (SEG)
- Reduce carbon footprint by ~4 tonnes per year
- Increase home value (typically adds 3-4% to property value)
- Protection against rising electricity prices
💡 Optimization Tips
- Combine with battery storage to increase self-consumption rate
- Time high-consumption activities (laundry, dishwasher) for midday solar peak
- Install smart meter to track generation and consumption
- Pair with heat pump for cheaper winter heating
- Clean panels annually for optimal output
- Get multiple quotes from MCS-accredited installers
- Check your feed-in tariff options (SEG rates vary by provider)
What a 5 kW System Actually Saves
A 5 kW solar system on a south-facing 30-degree roof in the UK generates roughly 5,500 kWh a year, the calculator's default. At an electricity price of 28p/kWh and an export tariff of 15p, with around 45 percent self-consumption, that is about £1,065 of annual benefit (£693 in bill savings plus £372 in export income). The system itself runs around £10,000 installed in 2026, and there is no specific UK grant for solar in 2026, though a £5,000 placeholder is included for any local council schemes that may apply.
The numbers swing significantly with orientation and angle. A north-facing roof loses about 30 to 40 percent of its potential output. A south-east or south-west facing roof at 30 degrees sits within 3 percent of optimal. East and west alone (without south) lose around 10 percent. The calculator applies the right performance factor automatically when you change the inputs.
Self-Consumption Is the Variable That Pays Back Fastest
The real economics of solar live in the self-consumption rate. Power used in your house is worth 28p/kWh (your bill rate); power exported to the grid is worth 15p (the Smart Export Guarantee rate from most suppliers). So a household that runs the dishwasher, washing machine and EV charger during the day captures roughly twice as much value per kWh generated as one that uses electricity mainly in the evening.
A battery raises self-consumption from around 45 percent to 70 or 80 percent, but adds £4,000 to £6,000 to the install. The payback maths gets tighter as battery prices fall, and there are useful hybrid inverter options if you might add a battery later. For the battery side specifically, [Solar Battery Payback Calculator](/solar-battery-payback-calculator) walks through the storage economics in detail.
Frequently Asked Questions
How much does a 5 kW solar system cost in the UK?
Around £8,500 to £11,000 fully installed in 2026, including panels, inverter, scaffolding, certification and labour. The default in this calculator is £10,000 (£2,000 per kW). Prices have fallen significantly since 2010 but installation labour is the slowest-falling component.
What is the payback period for solar in the UK?
Typically 9 to 13 years on a south-facing roof in southern England, longer in Scotland or on a north-facing roof. Households that use a lot of daytime electricity (work-from-home, EV charging, daytime appliance use) hit closer to 9 years; evening-only users land nearer 13.
Are there any UK government grants for solar?
There is no specific solar panels grant in 2026. The Boiler Upgrade Scheme (BUS) only covers heat pumps. ECO4 funding is available for low-income households for various energy measures including solar. Local councils sometimes run schemes; the £5,000 placeholder in this calculator is for those edge cases.
Do solar panels work on a north-facing roof?
Yes, but with around 30 to 40 percent less output than south-facing. East-west splits (panels on both sides of the roof) often work better than committing everything to the worse facing direction, because production spreads across the day rather than peaking at noon when nobody is home.
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