UK Solar and Heat Pump Deployment Data

Solar panels and heat pumps are the two pieces of low-carbon kit most likely to end up on an ordinary British house, and the official statistics on both are published monthly or quarterly by the Government.

They are also easy to quote wrongly, because three quite different things get reported under the same heading: how much has been built, how many grants have been applied for, and how many of those grants turned into an installation. This page keeps them apart.

Three measures that are not the same

Before any figure below means anything, it is worth being clear which of these you are looking at:

• Deployment — what physically exists and is generating or heating. For solar this is reported both as installed capacity in megawatts and as a count of installations, and those two move very differently.
• Retrofit installations — heat pumps fitted to existing homes. This is the harder and more meaningful number, because putting a heat pump into a house that already exists is a different problem from specifying one for a new build.
• Grant process measures — applications, vouchers issued, vouchers redeemed. These are stages in an administrative pipeline, not installations. A voucher issued is a household intending to install; only a redemption means something was fitted.

Treating a grant application as an installation overstates deployment, and it is done often. The figures below keep the three separate.

Deployment across Great Britain

Solar is reported monthly, heat pumps and scheme figures quarterly, and they cover slightly different geographies — which is why they are shown as separate cards rather than combined into a single total.

Solar in your constituency

Solar deployment is published by parliamentary constituency, so you can see how your area compares. Enter a postcode and we resolve it to a constituency code — the postcode itself is sent nowhere it is stored, never appears in the URL and is not logged.

Capacity is not output

Installed capacity is what a system could produce in ideal conditions. Output is what it actually produces, and for solar in Britain that is roughly a tenth of the theoretical maximum across a year.

The reason is unglamorous: it is dark half the time, often cloudy, and the sun is low for much of the year. A domestic array generates most of its annual total in a handful of summer months and very little in December and January — which is precisely when a household needs the most energy.

That mismatch is the central fact of domestic solar, and it is why battery storage and self-consumption matter so much more than they used to. Our solar panel calculator works through what a specific roof is likely to produce, and the weather and demand page explains why sunshine and demand run in opposite directions across the year.

What the grant schemes do and do not cover

The Boiler Upgrade Scheme is the main route to a heat pump grant in England and Wales. Scotland runs its own schemes, which is one reason the figures here are shown by nation rather than as a single total.

Two things about the scheme figures repay attention. First, the stages are separate: an application is not a voucher and a voucher is not an installation, and a meaningful share of vouchers expire unredeemed. Second, the grant covers the heat pump, not the house. If your home needs larger radiators or better insulation to run one well — and many do — that sits outside the grant.

The published figures also suppress very small cell counts to protect privacy in thinly covered areas. Those appear as unavailable rather than as zero, because a suppressed count is not the same as nothing happening.

Is either worth it for your home?

Nothing here is advice about your own property, but the deployment data does point at what separates a good outcome from a disappointing one.

Solar suits a roof with a decent southerly aspect and a household that uses electricity during daylight. Since the Feed-in Tariff closed to new applicants, the return rests mostly on the electricity you use yourself rather than what you export, so being home during the day, or shifting usage into it, matters more than it once did.

Heat pumps reward the house, not the weather. They deliver heat at a lower temperature than a gas boiler, so they need enough radiator or underfloor area to give that heat off, and they reward insulation heavily. A well-specified install in a poorly insulated house is the standard way to end up unhappy. Our guides to air source heat pumps and air source versus ground source go through the specification questions that actually decide it.

Either way, a working smart meter is worth having first: both technologies are cheaper to run on a tariff that prices by time of day, and those need half-hourly readings.