Guide · EPC
EPC ratings and solar funding in Wales
Your home's energy rating decides whether Nest can help, and it doesn't matter at all for some other routes. Here's how to find your rating, what each Welsh route asks for, and what to do if the certificate is old or missing.
In brief
Nest's benefit route needs a rating of E, F or G; its health route D or lower (a SAP score of 68 or lower). The Boiler Upgrade Scheme no longer needs a valid EPC, since 28 April 2026. The loan scheme, VAT relief and export payments don't use the rating. Look up your certificate by postcode on GOV.UK's register for England and Wales.
Checked at source on 3 November 2026 · An independent guide from SEO-DONS LTD, not the Welsh Government, Nest or a council
The certificate
What an EPC is, and how to find yours
An energy performance certificate rates a home from A, the most efficient, to G, the least, with a numerical SAP score behind the letter. An accredited assessor visits, records the construction, insulation, heating and any renewable technology, and software produces the rating and a list of recommended improvements. Certificates are needed when a home is built, sold or let, and each lasts ten years.
Homes in Wales are on the same public register as England. GOV.UK's "Find an energy certificate" service lets you search it by postcode. If your home has been sold or let in the last decade, a certificate probably exists.
Route by route
What each Welsh route asks for
| Route | Rating needed |
|---|---|
| Nest, benefit route | E, F or G |
| Nest, health route | D or lower (SAP 68 or lower) |
| Boiler Upgrade Scheme | None since 28 April 2026 |
| Warm Homes Loan Scheme | None in its published eligibility |
| 0% VAT | None |
| SEG export payments | None; a certified installation instead |
Nest's homes
How poorly rated Nest's homes are
The homes Nest deals with are often among the least efficient in Wales. Its 2024 to 2025 report notes that many of the properties were energy inefficient, with 42% rated E, F or G. The Welsh Government's report describes the rating used for the benefit route as indicative, which means the Nest team can assess the home as part of its process rather than relying only on an existing certificate.
So if you don't have a certificate, or yours is old, don't pay for a new one before contacting Nest: ask what it needs first.
Old, wrong or missing
If the certificate doesn't reflect the home
A certificate shows the home on the day it was assessed. If you've added insulation or replaced the boiler since, the rating may now be better than the certificate says, which could affect Nest eligibility either way. If you need a new certificate for another reason, an accredited domestic energy assessor can produce one; the assessor's accreditation scheme is shown on every certificate.
Be wary of anyone offering a "free EPC" as a way to get into your home for a sales visit. Genuine assessments for Nest are arranged by the Nest team.
The awkward case
When a better rating closes a door
Because Nest's routes need low ratings, a household on a low income in a home rated C won't qualify, and one rated D only on the health route. That's deliberate: the scheme targets the homes that are hardest to heat. It does mean that doing some improvements privately can move a home out of Nest's reach. If you think you might be eligible, check with Nest before paying for work you'd like funded.
Solar and the rating
Will solar improve my EPC rating?
Usually. The assessment method credits electricity generated on site, so a home with solar generally scores better than the same home without it. A better rating doesn't by itself mean lower bills, because it models a standard pattern of use, not yours. For homes that won't get Nest, the routes that don't use the rating apply: the loan scheme for owners, and 0% VAT and export payments for everyone.
The numbers behind the letters
Ratings and SAP scores
Each letter covers a band of SAP scores. Nest’s health route is defined by a score of 68 or lower, which corresponds to a D rating or below. A home near the edge of a band can move up or down a letter with a single improvement, which is why a recent certificate matters if your eligibility is close.
The certificate also shows a potential rating if its recommendations were carried out, and solar panels often appear among them.
Where to look
If you can’t find a certificate
If the register shows nothing for your address, the home may never have been assessed, or the address may be recorded differently: try the postcode alone and look through the list.
For Nest, you don’t need to commission one before contacting the scheme; ask what it needs first. For a sale or a new letting you’ll need a valid certificate anyway, from an accredited domestic energy assessor.
For landlords and sellers
When you need a certificate anyway
You need a valid energy performance certificate to sell or let a home, so if you're doing either, the certificate you commission for that purpose will also tell you where the home stands for Nest. Landlords with eligible tenants may find the rating is the starting point for a conversation about improvements that cost neither party anything. The recommendations section of a certificate is a useful, if generic, list of what would improve the rating most, and it often includes solar.
A rating is a snapshot of the building, not of the people in it, so two households in identical homes will have the same rating but very different bills. That's one reason Nest looks at the household as well as the home, through its benefit and health routes, before deciding what to fit.
If in doubt, ask Nest what evidence of the rating it needs before you spend anything.
Checked against
- Warm Homes Nest scheme annual report 2024 to 2025 (Welsh Government), read 3 November 2026
- Find an energy certificate (England and Wales) (GOV.UK), read 3 November 2026
- SI 2026/390, Boiler Upgrade Scheme amendments (legislation.gov.uk), read 2 November 2026
- Boiler Upgrade Scheme: what you can get (GOV.UK), read 3 November 2026
Not sure which scheme, if any, fits your home?
Tell us which council area you're in and what you're looking into. Your message reaches SEO-DONS LTD, the publisher of this guide, and we answer by email. We're not a scheme and can't approve anything, but we can point you to the right one.
What happens next
- Your message reaches SEO-DONS LTD, which publishes this guide.
- We reply by email with the scheme page that fits, if there is one.
- Any application is between you and that scheme.