Costs explained
What is included in a solar quote?
Compare system costs, equipment and the full installed price.
Read guide
Plan your solar
Solar savings calculator
Explore a starting estimate for your home. Change your electricity spend, property type and battery choice to see how the figures move.
Tell us about your home
No contact details needed. Your result updates as you change these choices.
An approximate monthly bill is fine.
Estimated annual savings
£714
£59 per month equivalent, under this model.
- Indicative installed cost
- £6,000–£8,000
- Simple payback
- 10 years Before maintenance or replacement costs
- Indicative system size
- 4 kW 10 panels at 400W
- Annual generation
- 3,330 kWh
- Energy used at home
- 45%Without battery storage
Where your solar electricity goes
1,499 kWh used at home
1,832 kWh exported
With a battery, “used at home” includes electricity stored for later. This model does not estimate battery losses or hourly energy flows.
Free to request. No obligation to buy.
What changes with a battery?
Both options use the same solar system and tariff assumptions.
Solar panels
Your selection- Annual savings
- £714
- Installed cost
- £6,000–£8,000
- Simple payback
- 10 years
Solar panels + battery
Your selection- Annual savings
- £926
- Installed cost
- £9,000–£13,000
- Simple payback
- 12 years
Under this model, a battery adds about £212 in annual savings and £3,000–£5,000 to the installed cost.
Higher savings do not automatically mean a shorter payback. Ask for a roof survey, battery specification and a forecast based on your actual usage.
See the assumptions behind this estimate
This model uses about 832 kWh a year per kWp, which is 3,330 kWh for a 4kW south-facing system in Belfast on the long-term PVGIS basis in our solar system sizes guide. It values electricity you use at home at 33.1p/kWh, the midpoint of Power NI's domestic unit rates of 32.10p to 34.15p including VAT from 1 July 2026, and exported electricity at 11.88p/kWh, Power NI's export rate from 1 October 2026 to 30 September 2027. It assumes 45% self-consumption without a battery and 75% with one. These are model assumptions, not a live tariff or a roof survey. The cost ranges are indicative and the payback calculation does not include maintenance, replacement, finance or tariff changes.
Roof orientation, shading, equipment and when you use electricity can change the result. Ask an installer for a tailored calculation before making a decision.
Make sense of the result
An estimate starts the conversation.
Your roof, shading and electricity tariff affect the system you need. Your installer should explain the assumptions behind their own proposal.
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Check the whole installed price
Ask what is included: panels, inverter, scaffolding, electrical work and any battery.
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Ask for a roof-specific forecast
Look for generation and savings estimates based on the direction and shading of your roof.
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Compare the aftercare
Understand the product warranties, workmanship cover and who you contact if something goes wrong.
