A solar panel installation is a regulated job with a clear order of steps. This page walks through that order, what it costs, what output to expect and how to compare quotes. Because Solar Yield is not an installer, we estimate openly. We pass your enquiry to MCS-certified installers only if you ask.
What an MCS-certified installation involves
MCS stands for the Microgeneration Certification Scheme. It certifies installers and sets the standards they work to. MCS also runs a Find an Installer search where you can check a company by name or certification number.
Certification matters in practice. For example, you generally need an MCS-certified installation to claim Smart Export Guarantee payments, as Ofgem’s SEG guidance explains. It also supports the zero VAT rate, covered below.
Step 1: survey
The installer checks your roof, its pitch and direction, any shading and your electrics. They may also look at your consumer unit and meter position. Because a good survey takes time, be wary of a quote with no visit at all.
Step 2: design and performance estimate
The installer then designs the array and picks the inverter. Under MIS 3002, they must estimate annual output as installed kWp multiplied by a regional kWh/kWp value and a shade factor. Therefore you should expect that estimate before you sign.
The standard calls the estimate guidance for the first year only, not a guarantee. We use the same honest framing, since guidance is all any estimate can be. Our yield calculator shows each assumption so you can challenge it.
Step 3: grid notification
Your network operator needs to know about the system. Specifically, ENA rule G98 lets a type-tested system up to 16A per phase connect first. That is about 3.68kW on a single-phase supply. The installer then tells the operator within 28 days of commissioning.
Larger systems fall under G99, however. The installer must apply and get approval before the work starts. The operator may also limit export or ask for network reinforcement. In Northern Ireland the equivalent is G98/NI, with 30 days to register with NIE Networks.
Step 4: installation
The team fits roof mounts, panels, an inverter and the cabling. They connect everything to your consumer unit. For example, ask the installer how long your roof will take.
Planning permission is usually not needed for roof panels in England, as the Planning Portal explains. Listed buildings are an exception. Our guide to solar panels and planning permission covers the rules in each nation.
Step 5: certification and export payments
After commissioning, the installer raises an MCS certificate and gives you the handover pack. You then choose a Smart Export Guarantee tariff. Each supplier sets its own rate, and the rate must be above zero.
At the time of writing, examples include 12p per kWh from Outgoing Octopus and 13p from E.ON Next Export Exclusive. Energy Saving Trust says a typical rate is around 12p. Our explainer on the Smart Export Guarantee shows how to compare them. The scheme covers Great Britain only, not Northern Ireland.
Typical system sizes and costs
Energy Saving Trust describes a typical home system as about 4.5kWp, with around 12 panels. Yet many installs are smaller. DESNZ counted 82,431 domestic MCS installs of up to 4kW and 85,469 of 4kW to 10kW in 2025/26. Sizes of about 2kWp to 6kWp are normal.
DESNZ cost data for 2025/26 gives a median installed cost of £1,595 per kW for systems up to 4kW. For 4kW to 10kW it is £1,546 per kW. That puts a 4kWp system at about £6,400, with a range near £5,600 to £7,200 for 3.5kWp to 4.5kWp. Energy Saving Trust gives a higher figure of around £7,600 for 4.5kWp.
These figures include equipment, installation and connection, but not a battery. Installing solar panels in a home is zero-rated for VAT until 31 March 2027, according to HMRC guidance. However, the 5% rate returns after that unless the government extends the relief, so check before you sign.
What output to expect
Because output depends on place, roof direction, tilt and shade, we use PVGIS data. Our figures are for a south-facing roof at 35 degrees. The figures below are kWh per kWp a year, then a 4kWp total.
For example, solar output in Plymouth reaches 1,122 kWh per kWp, or about 4,488 kWh from 4kWp. Solar output in Bristol is 1,023 kWh per kWp, giving about 4,092 kWh. Solar output in Leeds is 947 kWh per kWp, so about 3,788 kWh. Solar output in Glasgow is 853 kWh per kWp, so about 3,412 kWh.
That spread of roughly 30% from the south coast to central Scotland is real, but roof direction can matter as much. Energy Saving Trust says east or west facing systems get around 15% to 20% less than south facing ones. Our guide to east-west solar panels shows how a split roof can still work well.
Meanwhile, two guides help you read these numbers. The first explains how much a 4kW system generates and how that changes through the year. The second explains kWh per kWp, which is the unit behind every estimate. If your roof allows a choice, the best tilt angle for solar panels in the UK is close to 40 degrees.
How to compare quotes
Ask for at least three quotes, and make sure each one covers the same scope. Check the MCS certification number on the MCS site. Look at the size in kWp, the panel and inverter models, the stated annual output and the warranty terms.
Therefore compare cost per kWp rather than the headline price. A cheaper quote may use a smaller array, so the price per kWp is the fairer test. Our guide on how to check a solar quote gives a longer checklist.
Be cautious about pressure and large deposits. The Renewable Energy Consumer Code says members should not ask for more than 25% of the final price. Ask whether the installer belongs to RECC, and read the contract before you sign.
Payback is the question most people ask next. It depends on your use, your export rate and the price of electricity. Our guide to the solar panel payback period shows how to work it out for your own home.
Batteries, however, are a separate decision. Read about solar battery storage before you add one to a quote.
How the Solar Yield enquiry form works
Our form is simple. You enter your postcode area, roof details and contact details. We pass the enquiry to MCS-certified installers who cover your area, and they contact you directly.
We do not install anything, and we do not take part in your contract. Using the form costs you nothing, while you decide who to talk to. Our editorial policy explains how we handle this.
Next steps
Start with a rough number. Run your roof through the solar yield calculator and note the assumptions. When you are ready to talk to installers, request quotes and compare their estimates with yours.