Solar panels Home services renewal guide: when & how to switch

Headline - make your next solar move count

Why 2025 is a favourable moment

UK rooftop solar is scaling fast, aided by policy and incentives. Installations grew 22% in H1 2025 with nearly 100,000 home systems added, and Q1 marked the strongest start since 2012. More than 40% of new homes in England now include solar, and GB generation is up 32%. That momentum reduces risk and improves service choice for renewals and upgrades.

Solar is no longer niche in Britain - it is mainstream, measurable and maturing.

Who benefits most from this guide

If you already have panels approaching mid-life, your inverter is out of warranty, your bills have risen after tariff changes, or you are buying a home with an existing array, this guide is for you. It also helps first-time switchers deciding between renewing equipment, expanding capacity, or moving to battery storage to cut grid reliance.

Speak the language: essentials you will hear

• PV module: The solar panel converting sunlight to electricity.
• Inverter: Converts DC from panels to AC for home use. Typical lifespan 8-12 years.
• kW / kWh: kW is power capacity. kWh is energy used or generated over time.
• Battery storage: Stores surplus solar for later, improving self-consumption.
• MCS certification: Quality mark for installers and products recognised UK-wide.
• DNO approval: Permission from your Distribution Network Operator for grid connection changes.
• Feed-in Tariff legacy / SEG: Older FiT systems pay generation and export; Smart Export Guarantee pays for exports on newer systems.
• Part L and Future Homes Standard: Building rules driving higher efficiency and more solar in new builds in England, with comparable standards in Scotland.
• Degradation: Gradual output loss of panels over time, typically 0.3% to 0.8% per year.

The UK now has around 18 GW of installed solar capacity, expected to generate about 14.43 billion kWh in 2025, powering around 5 million homes. With 170,000 certified domestic renewable installs in H1 2025, service quality and availability are improving - a good backdrop for renewing confidently.

Your renewal choices at a glance

Upgrading is not one-size-fits-all. Consider these routes:

1. Replace an ageing inverter

• Best if your inverter is 8-12 years old or failing.
• Options include hybrid inverters ready for battery integration.
• Benefit: Restores efficiency and unlocks smarter monitoring.

2. Add battery storage

• Suits homes exporting regularly mid-day and importing evenings.
• Increases self-consumption, cushions time-of-use tariffs, and supports resilience.
• Look for modular systems to scale later.

3. Expand your array

• Add panels if roof space, DNO limits, and EPC targets allow.
• Useful with EV charging or heat pumps raising demand.

4. Full system refresh

• Consider if panels are >15 years old, heavily degraded, or poorly installed.
• Enables higher efficiency modules and optimisers.

5. Switch export tariff or supplier

• SEG rates vary and can be paired with smart tariffs.
• Sometimes the best return is a tariff change, not hardware.

Quick comparison

Costs and paybacks vary by roof, region, shading, and tariff.

What it means for your wallet and footprint

• Costs: Hardware prices are competitive due to record 2025 volumes and supply depth. Batteries remain the biggest line item.
• Savings: Higher solar generation in GB and sharper export options improve returns. Pairing panels with a smart tariff can stack benefits.
• Risks: Component mismatch, poor cabling, or unapproved capacity increases may void warranties or breach DNO rules.
• Impact: Upgrades can raise self-consumption to 60-80% with storage, cutting grid purchases and emissions where renewables now supply about 37% of UK electricity.

The cheapest unit of energy is the one you do not buy from the grid.

Can you switch or renew now?

• Property type: Most houses and many bungalows are suitable. Flats may require freeholder consent.
• Age of system: Inverter at 8-12 years signals renewal. Panels over 15 years merit a performance check.
• Electrical limits: DNO export thresholds apply. Exceeding them needs approval or export limiting.
• Certification: Insist on MCS installers and products for quality and eligibility.
• Roof and structure: Check fixings, waterproofing, and space for extra panels or a battery.
• Tariffs and metering: A smart meter simplifies SEG payments and time-of-use optimisation.
• Regional context: Areas like Argyll and Bute, The Cotswolds, and Ceredigion are leading adopters, which can mean more experienced local installers and competitive quotes.

If buying a home with solar, request documentation: MCS certificate, DNO letter, warranties, and generation data.

The practical route - step by step

1. Audit performance and warranties with 12-month generation data.
2. Define goals: bill savings, resilience, EV charging, or export.
3. Get three MCS quotes with clear scope and brands.
4. Check DNO limits and apply for approvals if expanding.
5. Choose tariffs: SEG rate and import time-of-use plan.
6. Schedule install, ensure scaffolding and electrical safety checks.
7. Commission, test, update MCS/SEG paperwork and warranties.
8. Monitor results via app and adjust usage patterns.

Upsides and trade-offs to weigh

Batteries improve self-sufficiency and resilience but add cost and may need ventilation space. Inverter upgrades usually pay back quickly through restored efficiency and warranty cover. Expanding arrays lifts output, yet DNO constraints or shading can cap benefits. Full refresh gives a modern, high-yield system but is the most disruptive. For some households, a smarter export or import tariff change outperforms hardware spend in the first year.

Red flags before you sign

• Quotes missing MCS accreditation or product datasheets.
• No roof survey or shading analysis provided.
• Vague payback claims without tariff assumptions.
• Ignoring Part L implications on renovations or future extensions.
• No plan for fire safety, isolators, and battery location.
• No mention of workmanship and product warranty lengths and transferability.

Ask for a written performance estimate with best, expected, and low scenarios.

If not this, then what?

• Energy efficiency first: Insulation, draught proofing, smart heating controls.
• Flexible tariffs: Move heavy loads to off-peak with EV or heat pump.
• Community energy or solar clubs: Access export benefits without hardware changes.
• Micro-wind or solar thermal: Niche cases in exposed or high hot-water-demand homes.
• Do nothing now: Revisit when warranty nears expiry or new incentives appear under the Solar Roadmap.

Questions homeowners ask

• When is replacement unavoidable? If the inverter fails, safety is compromised, or output drops sharply after ruling out shading or faults.
• Will I lose my FiT by upgrading? Panel swaps can affect FiT accreditation. Many keep panels and replace inverters only. Take supplier advice before changes.
• Is a battery always worth it? Usually when evening use is high, tariffs are time-of-use, and export rates are modest. Otherwise, start with inverter and tariff.
• How long will installers take? One day for inverter, one to two days for battery, longer if expanding array and scaffolding is required.
• What about grid limits? Your installer should manage DNO applications and may set export limits to comply.
• Are prices likely to fall further? 2025 volume is strong, but waiting carries opportunity cost. Compare savings from acting now versus potential price changes.

Your next move

• Gather your last 12 months of electricity usage and export data.
• Decide your priority: lower bills, backup, or faster payback.
• Get three MCS-certified quotes that specify kit, warranties, and expected yield.
• Compare tariffs alongside hardware choices to maximise returns.
• Choose an installation week and line up DNO and SEG paperwork.

Clarity first, kit second - let the numbers lead the decision.

Important notice

This guide is general information for GB homeowners. It is not financial advice or a substitute for professional surveys. Returns depend on your property, usage, tariffs, and approvals. Always use MCS-certified installers and confirm DNO and supplier requirements before proceeding.