Solar quote checker: what price per kWp tells you

How to use the checker

The free checker sits on the home page. It runs in your browser, so nothing you type is sent anywhere, because the tool runs on your own device. It does not accept files and it does not ask for contact details.

First, enter the total quoted price. Next, enter the solar array size in kWp, which is the panel capacity written on the quote. If the quote includes a battery, say so and enter its usable capacity in kWh. Then tick each item that the written quote makes clear, such as exact equipment models, scaffolding and electrical work.

The result has two parts. The first is a price per kWp. The second is a scope checklist that shows what the quote leaves vague. Run it once for each quote you hold, so the numbers sit side by side. Gaps then show up quickly.

What price per kWp tells you

A kilowatt peak (kWp) measures how much power the panels can produce under standard test conditions. Dividing the system price by that figure gives you one number you can compare across quotes. It also lets you compare a 4 kWp quote with a 6 kWp one, because size no longer skews the result.

You can then set that number against official data. Before you do, check the period and the capacity basis. The Department for Energy Security and Net Zero (DESNZ) publishes median installation costs from MCS records. The latest release covers April 2025 to March 2026 in Great Britain. It was published on 28 May 2026.

For installs of up to 4 kW, the median was £1,595 per kW of total installed capacity. For installs between 4 and 10 kW, it was £1,546 per kW. DESNZ also publishes the same data per kW of declared net capacity. On that basis the medians were £1,780 and £1,697. DESNZ says the costs based on installed capacity are typically 6 to 12 per cent lower.

Since a quote states panel capacity, the installed-capacity figures are the more natural comparison. However, a median is only a midpoint. Half of installs cost less per kW and half cost more.

DESNZ also notes that larger systems cost less per kW. The 4 to 10 kW median is lower than the up-to-4 kW median, so a 3 kWp quote will tend to show a higher figure than a 9 kWp one.

What the DESNZ figure includes and excludes

The DESNZ cost covers the generation equipment, installing it, connecting it to the supply and VAT where it applies. It does not cover a battery or an extended warranty. It also leaves out other works carried out alongside the panels, so a quote with extra jobs will look dearer.

So for a fair comparison, take the battery out first. A quote for panels and a battery will look expensive per kWp even when both parts are fairly priced. The checker handles this when you enter the battery details. For help judging the battery itself, read whether a solar battery is worth it and see what to check when adding a battery to existing solar panels.

Northern Ireland installs are not in the DESNZ data. Therefore, if you live there, treat the figures as a rough guide only.

What price per kWp hides

The number is useful, but it flattens a lot of detail. Four things move it most.

Battery and extra electronics

A battery adds a large cost of its own. If the quote does not split that cost, your per-kWp figure is inflated. Optimisers or microinverters can also raise the price. Our guide to inverter types and their trade-offs explains when that extra cost earns its place.

Scaffolding and access

Scaffolding is a real cost on most roofs. Some quotes include it and some list it as an extra. A quote that leaves it out may look cheaper until the invoice arrives. A high eaves line, for instance, needs more tower, so ask whether the quote covers it.

Roof complexity and panel layout

While a simple south-facing roof is cheaper to fit, several small roof faces cost more. Roof shape changes the labour, the number of strings and the cabling. It also changes how much power you can expect. Compare east-west and south-facing layouts before you decide that a higher price is unfair.

Electrical work and grid steps

A consumer unit upgrade, a longer cable run or a grid application can all change the total. For instance, a long cable run adds labour. The quote should say who pays for each. Our quote red flags guide lists the vague wording to look out for.

What the checklist is for

The scope checklist matters as much as the price. Under the MCS standard, an installer must give you certain information in writing at or before the point you award the contract. That includes the performance estimate, the manufacturer datasheets for the panels and inverter, and a drawing of the proposed panel layout.

The Renewable Energy Consumer Code adds more, although it applies only to member installers. Its member installers must itemise goods and services, show the price of goods and services separately, and list what the quote leaves out. A tick in the checker means the item is clear in writing. It does not mean the work is good.

For the full list, read what a solar quote should include. To judge the system size behind the figure, see how many solar panels you need.

Reading the result in practice

Suppose your quote lands near the DESNZ median. That is a sign the price is in the usual range, nothing more. Suppose it sits far above or far below. Then ask the installer why, in writing, before you go further, because a clear answer tells you a lot.

Prices also differ across the country. Labour, access and travel all play a part, so read local pages too. Our pages on solar quote prices in the North East and what to expect in the North West show how local factors can change a quote.

Finally, check how you will pay. A good price is no use if the payment terms leave you exposed. Our guide to deposit and payment checks covers deposit limits and protection.

Next steps

Once you have a price per kWp and a list of gaps, you have three options. None of them requires you to commit. You can look at typical solar panel costs to put your figure in context. You can follow our method for comparing solar quotes like for like. Or you can ask for MCS-certified quotes to set beside the one you hold.

Solar Panel Price Check is independent. We are not an installer, lender or broker, and the checker cannot say whether a price is fair or a design is right for your home. It only makes the quote easier to question.