01Prices
Every seller's latest price
Sorted by price, then by the date we read it. One price type and grant state is compared; any other sits apart and says so.
Not checked yet
We have not read a price for this spec from any seller yet, so there is no figure here. These sellers are on our list for solar panels; each price will show with its type, grant state and the date we read it.
02Index
The weekly index
The median of one price type across the sellers read in the last 14 days, week by week.
Index not started
The index needs three sellers with one price type, each read in the last 14 days, and two weeks of it to draw a line. It starts here once the weekly runs have that.
03Grants
Grants that can pay towards it
Grants differ by nation: each one says where it applies.
04Like for like
What counts as this spec
A seller's price is matched by its stated size and scope, never by price.
3.5 to 4.5 kWp on a pitched roof, with panels, inverter, scaffolding and installation. Panel brand, wattage, bird proofing and optimisers are recorded, not required. Ground mounts, flat roof frames, in-roof systems and prices without scaffolding are off the comparison.
A price for a different size or scope is stored with the date we read it but kept off this comparison. A price after a grant is never put beside one before it without saying so.
05Questions
Solar panels, 4 kWp: questions
- Solar panels, 4 kWp: how much does it cost?
- Solar panels, 4 kWp: not checked yet. We have not read a price for this spec from any seller; the first weekly run fills it, every price with the date we read it.
- Which seller is cheapest?
- Solar panels, 4 kWp: we cannot say yet. No seller has a price read in the last 14 days, and we only call a seller cheapest on a reading from the latest weekly run.
- Is there a grant?
- Warm Homes: Local Grant (pays for agreed work): England only. Wales, Scotland and Northern Ireland: none of the grants we track. Each grant page says who qualifies, checked on the official page.
- How are these prices read?
- From each seller's own website, once a week, with the date we read it. Every price says its type (from, fixed or typical) and whether a grant has been taken off. Commission never changes the order.
06Sources
Where these figures come from
- Warm Homes: Local Grantchecked 31/10/2026
- How we read prices