What is the Gasketelwet? BRL 6000-25 and K25000 explained

Since 1 April 2023 not every installation company may simply work on a central heating boiler, gas fire or other gas-fired combustion appliance. The Gasketelwet — the everyday name for an amendment to the Woningwet — ties that work to mandatory CO certification. For refrigeration and HVAC companies that also maintain gas-fired installations (think of a hybrid heat pump with a gas boiler as peak provision) this is a separate obligation alongside everything you already arrange around F-gases and BRL 100. This article sets out what the law involves, which certification routes there are and what is at stake.

What does the Gasketelwet involve?

The Gasketelwet is not a standalone act by that name — it is the popular term for an amendment to article 2 of the Woningwet. Since the Omgevingswet took effect on 1 January 2024, it has been set out in section 6.5.5 of the Besluit bouwwerken leefomgeving (Bbl) — the successor to the former section 1.8 of the Bouwbesluit 2012. Two articles matter most here:

• Article 6.45 (certification requirement) prohibits carrying out work on gas-fired combustion installations, flue gas discharge provisions and combustion air supplies without a valid certificate — formerly article 1.35 of the Bouwbesluit 2012.
• Article 6.46 (CO reporting duty) requires (near-)accidents to be reported — formerly article 1.38 of the Bouwbesluit 2012.

The trigger was an investigation report by the Onderzoeksraad voor Veiligheid (OvV) into carbon monoxide accidents: too often, fatal CO poisoning turned out to be traceable to incompetent work on central heating boilers and flue gas discharge. The purpose of the law is therefore direct — to demonstrably improve the quality of installation and maintenance work on gas-fired combustion appliances, with a certification requirement as the instrument. The scheme applies to building-related gas-fired combustion appliances up to 100 kW: central heating boilers, gas water heaters, gas fires and air heaters, including the associated flue gas discharge and combustion air supply.

Gasketelwet vs the F-gas Regulation: two separate worlds

Watch out for the confusion that quickly arises here: the Gasketelwet is about gas combustion — the safety of the combustion process itself and the risk of carbon monoxide. That is something fundamentally different from the F-gas Regulation, which is about refrigerants in refrigeration and air conditioning installations and turns on leakage and greenhouse gas emissions. Both use the word "gas", but they are two separate regimes with their own certificates, their own certification bodies and their own legislation.

For a pure refrigeration installer who does not touch gas-fired combustion appliances, the Gasketelwet is not relevant. But as soon as your company also maintains hybrid heat pumps — an electric refrigerant circuit combined with a gas boiler as peak provision — you can end up dealing with both regimes at once, and sometimes even within the same work order.

BRL 6000-25 or BRL K25000 — which do you need?

To comply with the Gasketelwet you choose a certification track. There are two common routes:

• BRL 6000-25 (InstallQ) — the standard route for installation companies, also suitable for companies that already hold a BRL 6000-AB certificate.
• BRL K25000 (Kiwa) — an alternative route aimed mainly at sole traders and small companies; part of the audit can take place remotely.

Both routes are set up to meet the same statutory requirement — which one fits depends on the size of your company and which certification body you already know from other work. If in doubt, request a quote from both; the core of what you have to demonstrate (which work, by whom, with what result) is the same in each.

Both certifications have a validity period with periodic surveillance audits in order to keep the certificate — the exact term and the number of interim check moments differ per certification body. Ask Kiwa or InstallQ about this specifically before you start a track.

Who has to be certified?

Two levels, just as with F-gases:

• The company needs the BRL 6000-25 or BRL K25000 certificate in order to be allowed to offer work on gas-fired combustion installations.
• The technician carrying out the work needs a Bewijs van Vakmanschap CO — the personal-level proof that he or she is professionally competent. See CO-person certificate: what you need to know for the details.

Without both, the work may not be carried out — comparable to how the company certificate and the BRL 200 personal certificate go together for F-gases (see Applying for an F-gas certificate).

What if you work without valid certification?

Article 6.45 of the Besluit bouwwerken leefomgeving (Bbl) prohibits carrying out this work without a valid certificate — that is a public-law norm which municipal building and housing supervision can enforce. Quite apart from that, there is a real practical risk: a work order or inspection report signed off by a technician without a valid Bewijs van Vakmanschap CO does not hold up at an audit — or worse, after an incident. In the case of CO poisoning, the liability question afterwards is the first thing the insurer and the regulator look at, and "who did this, and was that person authorised to do so" is then the first question asked.

How Koldwerk supports this

Koldwerk's CO inspections module only starts on an installation of type gas combustion or hybrid, and blocks the inspection if the selected technician does not hold a valid CO-person certificate — the same hard link that work order sign-off already enforces for F-gas work. Per inspection you record the CO concentration unloaded and under load, run through a fixed checklist (combustion air supply, flue gas discharge, installation space) and get a chronological inspection history per installation with a downloadable report. See CO inspection: checklist and work order requirements for what that inspection looks like in practice.

Further reading

• CO-person certificate: what you need to know
• CO inspection: checklist and what needs to be on your work order
• The F-gas Regulation explained for technicians — the refrigerant regime alongside the Gasketelwet
• What is BRL 100? — the process certification for refrigeration and air conditioning installations

Disclaimer: this article is an explanation in plain language, based on the amendment to article 2 of the Woningwet, in force since 1 April 2023 and, since the Omgevingswet took effect on 1 January 2024, set out in section 6.5.5 of the Besluit bouwwerken leefomgeving (Bbl, art. 6.45 and 6.46) — formerly section 1.8 of the Bouwbesluit 2012 (art. 1.35 and 1.38) — and on public information from Kiwa and InstallQ. Consult Kiwa (opent in nieuw tabblad) or InstallQ (opent in nieuw tabblad) for the current position and the exact certification requirements. Not legal advice.