ENplus and DINplus certificates — what they really mean

Two marks appear on pellet bags: ENplus and DINplus. Both mean something real and both rest on the same standard — but they differ in what exactly they control. Below: what they guarantee, how they differ, how to check whether the certificate on the bag actually exists, and how to tell them apart from private marks.

What a certificate is for at all

A producer can print "A1" on a bag and nothing follows from it — it's just a caption. A certificate is something else: an independent body tests the fuel and audits the producer, and assigns the result to a number that can be looked up in a public database.

So a certificate doesn't say the pellets are "good" in the everyday sense. It says something more specific: that they meet the standard's measurable thresholds and that someone checked this independently.

ENplus

ENplus rests on the requirements of ISO 17225-2 and in several respects goes further than the standard itself. Two worth remembering:

• The scheme allows no demolition wood or chemically treated wood in any class — including the lowest class B.
• Certification covers not just the fuel but the whole supply chain: production, repacking and trading. That matters, because good pellets can be ruined by bad transport and storage, crumbling on the way.

ENplus comes in three classes — A1, A2 and B — and the specific thresholds for ash, durability and calorific value are set out in A1 vs A2.

DINplus

DINplus is issued by DIN CERTCO, part of TÜV Rheinland, the only body entitled to grant the DIN mark for pellets. Certification rests on DIN EN ISO 17225-2 and, importantly for the buyer, applies exclusively to class A1 pellets — there is no such thing as "DINplus A2".

Testing covers moisture, bulk density, fines, calorific value, mechanical durability, ash, pellet length and chemical contaminants. The certificate is valid for five years subject to a positive annual surveillance — for producers that means a yearly inspection with samples taken for laboratory testing.

Which is better

From the point of view of someone buying for a domestic boiler: both are credible and both rest on the same ISO 17225-2 standard. There is no reason to reject pellets just because they carry one mark rather than the other.

One practical difference worth noting: since DINplus applies only to class A1, the DINplus mark on a bag by itself implies class A1. With ENplus you have to look at which class is stated next to the mark — because ENplus A2 is also a valid ENplus certificate, just for looser thresholds.

How to check whether a certificate is real

A logo can be printed. A number in a database cannot.

1. Find the certificate number on the bag or the product page. If a shop boasts of a certificate but never gives the number, that's a warning sign.
2. Check the number in the certifying body's public database — DIN CERTCO runs a database for verifying certificate validity; ENplus keeps its own register of producers and traders.
3. Check the details match — that the number belongs to the producer whose pellets you're buying, and that the certificate is still valid.

That third step is often skipped and it matters: the certificate may have expired or may cover a different product line from the same plant.

Marks that are neither ENplus nor DINplus

Other "certificates" also appear on bags and in shops: private quality programmes, distributors' own marks, titles from consumer surveys. An example we came across while profiling the Koala brand: a document called a certificate, issued by a one-person firm under its own "Polski Pellet A1" programme, citing the same ISO 17225-2 standard. Such a document may rest on sound tests — but it cannot be checked in any public register, and nothing is known about the issuer's procedures or accreditation.

A simple rule: a certificate whose number you can't find in the ENplus or DIN CERTCO register should be treated as a seller's declaration. It may be true; it's just that nobody independent vouches for it. Likewise, titles such as "Consumer Quality Leader" speak to customer satisfaction, not to ash content.

What we do with certificates in our table

We show class and certificate only when the shop itself declares them on the product page. We add nothing from the product name or the marketing copy.

When a shop gives no class, the offer goes into the price table marked as unknown class — visible for transparency, but it will never trigger a price alert. We don't want to notify you of a bargain on fuel whose quality we have no information about from the source.

We do not, however, verify certificate numbers in the certifying bodies' databases — you'll do that yourself before buying, using the three steps above. We say so openly so as not to suggest a check we don't perform. A full description of what we check and what we don't: /metoda (Polish).

Sources

• ENplus® ST 1001:2022 — ENplus® wood pellets: Requirements for companies (Bioenergy Europe / DEPI) — quality classes, permitted raw materials, and the exclusion of demolition and treated wood.
• DIN CERTCO — DINplus certification for wood pellets (TÜV Rheinland) — normative basis, scope of tested parameters, five-year validity with annual surveillance, and the database for verifying a number.