Cost solar PV install.

With the UK government's commitment to net-zero and the current 0% VAT rate on energy-saving materials, there has never been a better time to invest. This guide breaks down the costs, technical requirements, and essential regulations for a successful installation.

What Does the Work Involve?

• Site Survey: An engineer assesses your roof orientation, pitch, and structural integrity, while checking for potential shading from trees or chimneys.
• Scaffolding: Safe access is required for almost all domestic roof installations, typically erected a day before the main work begins.
• Roof Preparation: Installers remove or lift tiles to secure mounting brackets directly to the roof rafters.
• Frame & Panel Fitting: An aluminium rail system is fixed to the brackets, and the solar panels are clamped securely into place.
• Electrical Wiring: DC cabling is run from the panels into the loft space, connecting to an inverter that converts the power to AC for home use.
• Grid Connection: The system is integrated into your existing consumer unit and a generation meter is installed to track production.
• Commissioning: The installer tests the system, sets up monitoring software, and provides MCS certification for your Smart Export Guarantee (SEG) application.

Typical Costs

The cost of solar PV has dropped significantly over the last decade. Most UK homes opt for a 4kW to 6kW system, which typically provides enough power for a family of four.

Prices are currently impacted by the 0% VAT rate on solar installations in Great Britain, which is scheduled to remain in place until March 2027. Total costs vary based on panel efficiency, inverter quality, and the complexity of your roof.

Pro Tip: Adding a battery at the time of installation is usually cheaper than retrofitting one later, as you save on additional labour and can often use a "hybrid" inverter.

How Long Does It Take?

• Pre-installation: 2–4 weeks for surveys, DNO (District Network Operator) applications, and equipment ordering.
• Scaffolding: 1 day to erect and 1 day to dismantle.
• Main Installation: 1–2 days for a standard domestic roof.
• Commissioning & Paperwork: 2–3 hours on the final day of the build.

DIY or Professional?

Solar PV installation is not a DIY project. While a competent person might physically mount a panel, the electrical work must comply with Part P of the Building Regulations.

Crucially, you must use an MCS-certified installer to qualify for the Smart Export Guarantee (SEG). Without this certification, UK energy suppliers will not pay you for the excess electricity you export to the grid, significantly extending your "break-even" period.

Choosing the Right Tradesperson

• Check Certifications: Ensure they are MCS (Microgeneration Certification Scheme) accredited.
• Consumer Protection: Look for membership in RECC (Renewable Energy Consumer Code) or HIES (Home Insulation & Energy Systems Quality Assured Council).
• Insurance: Verify they have public liability insurance and offer an insurance-backed guarantee.
• Questions to ask:
  • Are you using a string inverter or micro-inverters (better for shaded roofs)?
  • Will the mounting system affect my roof warranty?
  • Do you handle the DNO (grid connection) application on my behalf?
  • What is the expected annual generation in kWh for my specific roof?

UK Regulations

• Permitted Development: Most roof-mounted solar installations do not require planning permission, provided they don't protrude more than 200mm from the roof plane.
• Listed Buildings & Conservation Areas: You will likely need formal planning permission and should consult your local authority first.
• Building Regulations: The installation must be notified to the local council; an MCS-certified installer handles this automatically.
• G98/G99 Notifications: Systems under 3.68kW per phase usually only need a "fit and inform" (G98) notice, while larger systems (G99) require prior approval from the grid operator.

Common Problems

• Inverter Placement: Installing inverters in poorly ventilated, hot lofts can reduce their lifespan; ensure they have adequate airflow.
• Roof Leaks: Using "universal" flashing kits instead of specific roof-type anchors can lead to water ingress over time.
• Pigeon Infestation: Birds love the warmth under panels; failing to install bird mesh during the initial build often leads to expensive cleaning bills later.
• Shading Oversights: Even a small amount of shade on one panel can significantly drop the performance of the entire "string" if not designed correctly.

Frequently Asked Questions