Quote checker: paste your numbers, get a sanity check

Solar quotes are hard to compare because they are quoted as a single number for a job that has at least four variables in it. This checks the numbers you were given against sources you can go and read.

Two figures get you the main check. The rest add more.

What each check measures against

Cost per kW — the Department for Energy Security and Net Zero’s official statistics series, derived from the MCS Installation Database, for the size band your system falls in. Median and mean, with the installation count behind them. The full table, and the dataset.

The generation estimate — our own PVGIS runs for 25 reference locations: 1 kWp, crystalline silicon, building-mounted, 20% system losses, 35 degrees, due south. That combination is a ceiling rather than a prediction, which is what makes it useful for testing a claim.

The saving figure — worked backwards into the self-consumption it implies, using the current price cap unit rate and the median open untied SEG rate, then compared with the 14–23% MCS’s own guidance note MGD 003 gives for a typical household with no battery.

A bundled battery — taken out of the total before the cost-per-kW comparison, where you can tell us what it cost. Where you cannot, the comparison is refused rather than made badly: the official benchmark is a solar installation cost, and dividing a solar-plus-storage total by the panel capacity produces a number that is not comparable with anything.

The battery — against nothing, because there is nothing. No UK price series for domestic storage exists that we would stand behind, so the tool reports cost per usable kWh for comparing quotes with each other and says plainly that it has no market to compare it with.

What it cannot do

It cannot tell you whether the installer is any good. Every check here is arithmetic. Workmanship, roof penetrations, how the scaffolding is handled and whether the company is still trading when you need the warranty are not in any dataset, and the one that would tell you most — MCS’s own certification data — is published under terms that forbid republication.

It cannot see your roof. Shading, orientation, pitch, the state of the tiles and whether the loft can take a battery all change the answer and none of them are inputs here.

A quote that passes every check can still be the wrong purchase, and one that fails a check can still be the right one with a good explanation. The point of the tool is to tell you which questions to ask, not to grade the quote.

Nothing leaves your browser

There is no form submission, no storage and no logging. We never see your quote, and there is nothing to unsubscribe from afterwards. That is deliberate: a quote checker that harvests quotes is a lead generator wearing a disguise.