Guides
The three questions everyone asks before the calculators — answered properly, with 2026 numbers and the caveats left in.
How do solar panels work?
From sunlight to your kettle: photovoltaic cells, inverters, and what “kWp” actually means for a UK roof. Plus what happens at night, in winter, and in a power cut.
Read the guide →How long do solar panels last?
25-year warranties, slow degradation, and the one component that won’t last the distance. What really wears out, what it costs to replace, and how to keep output up.
Read the guide →Are solar panels worth it in 2026?
The honest maths at the October 2026 price cap: a worked 4kW example, the roofs that pay back fastest, and the situations where we’d tell you to keep your money.
Read the guide →Prefer to run your own numbers?
Solar panel cost calculator
What a solar system costs for your roof size, with or without a battery.
Open calculator →How many panels do I need?
Panels, roof space and system size worked out from your electricity use.
Open calculator →Solar battery cost & sizing
The battery size that fits your evenings — and what it should cost.
Open calculator →Solar payback calculator
When a system pays for itself, year by year, at today’s prices.
Open calculator →Solar savings estimator
Year-one and 25-year savings from any system size.
Open calculator →SEG earnings calculator
What your exported solar electricity earns under the Smart Export Guarantee.
Open calculator →New boiler cost
Replacement combi, system and regular boiler prices for UK homes.
Open calculator →Heat pump cost
Air source, ground source and air-to-air prices after available grants.
Open calculator →Heat pump vs boiler
Running costs compared honestly at October 2026 energy prices.
Open calculator →Insulation savings
Loft and cavity wall insulation costs, savings and payback by house type.
Open calculator →Grant eligibility checker
ECO4, the Boiler Upgrade Scheme and Warm Homes — who qualifies, and by when.
Open calculator →EPC rating estimator
A rough A–G band for your home, plus the three upgrades that help most.
Open calculator →