How we map and grade nearly 15 million roofs.
From laser scans taken from the air to a graded home you can write to, in one searchable map of mainland Britain.
Measured from the air
LiDAR stands for light detection and ranging. Survey planes fly over the country firing laser pulses at the ground and timing how long each one takes to bounce back. Millions of these measurements build a 3D picture of every street.
From those measurements we work out each roof's shape: its pitch, which way each face points, and how much of it is usable for panels.
From points to homes
Every roof, shaped
Points alone are not enough. We fit each building to a real roof type, such as gable or hip, and flag any roof where the evidence is weak.
A roof is a home
Every roof is matched to a real address, so each one is a home you can write to.
What is this building?
Open map data and public energy records tell homes apart from shops, flats, listed buildings and known council property. They come out before anything is graded.
The grade
What is left is graded A+, A, B or C, combining four things:
- Usable roof area: how much room there is for panels.
- Direction: south counts most.
- Roof shape: simple shapes suit panels best.
- Confidence: how sure we are of the data. Where there is no evidence either way, we stay cautious.
From that we estimate a system size and what it could generate, which is what each homeowner sees in their letter. It is a desktop estimate, not a survey, and the letter says so.
Checked again after you pay
Before anything is printed, every home gets a second look: a visual check for existing solar panels, and every address confirmed. Any home that does not pass is removed, and its credit comes back to you.
That is how Targeted Mailshot and Tell the Neighbours make sure every letter goes to a roof worth writing to.
Video transcript
Read the transcript
Every installer knows the best leads are good roofs owned by people who'll say yes. But roof suitability isn't on any list. So we built one. It starts with LiDAR. Survey planes fly over the country firing laser pulses at the ground, and time how long each one takes to bounce back. From millions of these measurements, we work out every roof's shape: its pitch, which way each face points, and how much of it is usable. Points alone aren't enough. We fit each building to a real roof type, gable, hip and more, and flag any roof where the evidence is weak. Next, we match every roof to a real address, so each one is a home you can write to. Then we ask what each building actually is. Open map data and public energy records tell homes apart from shops, flats, listed buildings and known council property. They come out before anything is graded. And where there's no evidence either way, we stay cautious. What's left is graded A+ to C, combining usable roof area, direction (south counts most), roof shape, and how confident we are in the data. From that, we estimate a system size and what it could generate. All of this is processed, tile by tile, across mainland Britain: nearly 15 million roofs, mapped and graded, in one searchable database. Pick a postcode, and every graded home around it appears in seconds. After you pay, we check again: a second look for existing panels, and every address confirmed. Any home that doesn't pass is removed, and its credit comes back to you. It's a desktop estimate, not a survey. But it means every letter goes to a roof worth writing to. Graded roofs. Personal letters. Printed and posted for you. Pay as you go. That's Solar Mailshot.
Common questions
What is LiDAR?
How many roofs does Solar Mailshot cover?
What does the roof grade mean?
Which buildings are removed?
Is the estimate a survey?
What if a home already has solar panels?
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