Solar Panel Installation: What Real UK Owners Actually Say

Getting solar panels installed is not complicated — but it does have more moving parts than most people expect. The quotes are easy enough; it is the phase between signing and switching on that catches owners off guard. DNO applications, scaffold logistics, a two-hour power cut on install day, and an inverter app that needs setting up before you can claim Smart Export Guarantee payments — none of this is hidden, but very little of it appears in a typical sales brochure. Here is the frank account UK owners tend to share only after the job is done.

What surprises people at quote stage

Roof condition issues can add real cost. Most reputable installers carry out a physical site survey before providing a final price. If your roof tiles are cracked, lifted, or the felt underneath is deteriorating, they may flag a reroofing job as a prerequisite. On homes built before 2000, an asbestos survey is sometimes required before drilling or cutting — this is a legal obligation under the Control of Asbestos Regulations 2012, and a type-2 survey typically costs £200–£400 depending on property size.

Consumer unit upgrades catch people off guard. If your existing consumer unit (fuse board) is outdated — older metal-clad boards with rewireable fuses, for example — your installer's electrician may require it to be upgraded to a modern unit with RCD protection before they can connect the inverter. This work is entirely separate from the solar quote and can add £400–£900 to the overall bill. Ask your installer explicitly whether their survey includes an electrical check, and whether any consumer unit work would be quoted separately.

Long cable runs cost more. The inverter must connect to your consumer unit. In a detached garage, an outbuilding, or a home where the consumer unit is at the opposite end from the roof entry point, the cable run can be long and labour-intensive. Get this confirmed in writing before you sign.

Scaffolding is not always included. Some quotes include scaffold erection and removal; others treat it as a separate line item. Always ask. For a typical two-storey semi-detached, scaffolding is usually erected the day before the panels go up and removed one to two days after completion. The cost, where charged separately, is typically £300–£600.

The DNO application — and why it matters

Every grid-connected solar installation requires a notification or approval from your Distribution Network Operator (DNO). The threshold that most households hit is governed by two engineering standards:

• G98 — applies to systems up to 3.68 kW AC export capacity (single-phase). Your installer notifies the DNO after installation, within 28 days of commissioning. No pre-approval is needed.
• G99 — applies to systems above 3.68 kW. Pre-approval is required before the installation begins. Fast-track G99 gives the DNO up to 20 business days (roughly four weeks) to respond, so factor this into your timeline.

A typical 4 kW system on a single-phase supply will trigger G99. Your installer handles the application, but delays do happen — especially in areas where the local grid is already heavily loaded. If you are told the DNO has imposed an export limiter (a device that caps how much power you can export to the grid), this is not unusual in constrained areas; it does not affect your self-consumption at all, only what you can earn from the Smart Export Guarantee.

What to expect on installation day

The scaffolding usually goes up the day before. A separate crew erects the working platform — typically around the rear and one side of the house. This is standard and takes a few hours.

The install crew arrives in the morning with panels, racking rails, the inverter, cabling, and fixings. For a standard 4–6 kW residential system on a straightforward roof, the roof work takes most of the day. The electrical work — running DC cabling from roof to inverter, wiring the inverter to the consumer unit, fitting the generation meter or import/export meter — takes place in parallel, usually in the afternoon.

Expect a power outage of one to two hours while the electrician isolates the consumer unit to connect the inverter. Your installer should give you advance notice of the window. Most households find the easiest approach is to treat it like a planned power cut — charge laptops beforehand, avoid running a dishwasher or washing machine mid-cycle.

Total installation time is typically one to two days for a residential system. Larger or more complex roofs (multiple aspects, many panels, a battery being added at the same time) may run to two full days. The installers will commission the system, walk you through the inverter display and app, and hand over the MCS certificate and warranties before they leave.

The monitoring setup owners often miss

Your inverter manufacturer's app is not the same as your export payment setup. The app (GivEnergy, SolarEdge, Fronius Solar.web, Solis Cloud, etc.) tracks generation and consumption in real time — genuinely useful. But to actually get paid for energy you export, you need to sign up to a Smart Export Guarantee tariff with an energy supplier. That requires an eligible smart meter and an MCS certificate. See our solar costs and savings guide for how much SEG payments are worth in practice.

CT clamp placement matters more than people realise. The current transformer (CT clamp) that clips around your meter tails tells the inverter and battery (if fitted) what the house is importing and exporting. If it is fitted on the wrong cable, or on the wrong side of the main switch, the system will misread consumption — the battery may discharge at the wrong time, or the monitoring app will show odd numbers. Ask your installer to walk you through where the CT clamp is fitted and confirm it is reading correctly before they leave.

Common post-install issues

Inverter fault codes are the most frequent reason people call their installer in the first year. Most are benign — a grid voltage fluctuation, a brief communication dropout, a WiFi dongle that lost its connection after a router change. Check your inverter brand's fault-code guide online before calling; most issues resolve with a simple restart. If generation drops significantly without a fault code, check for shading from a newly grown tree, a dirty panel, or a loose DC connector.

Export limiter settings occasionally need adjusting if you add a battery or EV charger after your original installation — the DNO-approved export limit was set for the original system configuration. Inform your installer whenever you add new generation or storage equipment.

Finding a good installer

MCS certification is the non-negotiable baseline. Check your installer on the MCS Find an Installer tool before signing anything. Without MCS certification, you cannot register for the Smart Export Guarantee, and the installation will not be covered by the Consumer Code protections. The Energy Saving Trust recommends getting at least three quotes from MCS-certified installers.

Beyond MCS, look at Trustpilot reviews (filter for verified purchases), check whether the company is a member of the Renewable Energy Consumer Code (RECC), and ask how long they have been operating. A five-year-old installer with 200 Trustpilot reviews is a safer bet than a two-year-old company with none.

Ten questions to ask every installer before signing

1. Are you MCS-certified, and can I verify your certificate number?
2. Is scaffolding included, and how many days will it be up?
3. Will you carry out an electrical check — and is any consumer unit work quoted separately?
4. Does my roof need any repair work before you can install?
5. Is my property pre-2000? If so, have you factored in an asbestos survey?
6. Which DNO application route applies (G98 or G99), and will you handle it?
7. What inverter brand are you specifying, and what is its monitoring app?
8. Where will the CT clamp be fitted, and how will I know it is working correctly?
9. What warranties cover panels, inverter, and workmanship — and are they backed by the manufacturer or just the installer?
10. What aftercare do you offer, and who do I call if there is a fault in year two?

Getting the answers in writing — ideally in the quote document — is the single most effective way to avoid the surprises that UK owners most commonly report after the job is done. Pair this with our guide to whether solar panels are worth it to check the numbers stack up before you commit.