Sole trader in refrigeration engineering: which certificates and insurance do you need?

You're a sole trader, you work on refrigeration installations and heat pumps, and you notice that "just a VCA course and a KVK registration" falls well short of enough. In refrigeration engineering, sole proprietorships face the same certification obligations as large installation companies — you just have to carry them on your own. This article sets out which certificates you personally need, when you must hold a company certificate yourself, and which types of insurance are worth considering.

BRL 200: the personal certificate always applies, without exception

If you work on equipment containing F-gases — air conditioners, heat pumps, refrigeration installations, refrigerated transport — you need a valid BRL 200 personal certificate (category A1, A2, B, C, D or E, depending on the type of work). That applies to everyone who carries out this work, so also to sole traders, and there is no exception based on company size. This certificate is valid for 7 years.

How you apply for this certificate and what the exams per category involve is covered in Applying for an F-gas certificate: how it works and BRL 200 F-gases — what your technician's personal certificate covers.

BRL 100: the company certificate — here it becomes less clear-cut for sole traders

The BRL 100 company certificate is intended for companies that independently carry out work on F-gas installations belonging to third parties (customers). The official guidance from Ondernemersplein/ILT is firm on this: as a sole trader working with F-gases, you need both a personal certificate (BRL 200) and a company certificate (BRL 100). This is the rule you should assume applies in practice.

In addition, certifying bodies and training providers circulate descriptions of a possible exception: if, as a sole trader, you work exclusively on the basis of a written agreement in which an already BRL 100-certified company records that you carry out F-gas operations on their behalf, you might not need a company certificate of your own. This exception is not mentioned consistently, or with the same degree of certainty, across the channels we consulted for this article — one source describes it explicitly, the other (including the ILT guidance itself) does not mention it.

So don't simply assume this without having it confirmed yourself. Ask your certifying body (Kiwa, DEKRA, Bureau Veritas, SGS or similar) or the client you put this to, explicitly whether your situation falls under this arrangement — and then actually record the written agreement, verbal agreements are not sufficient. If you work for varying clients or independently, assume that you simply need your own BRL 100.

A second point to keep in mind: if you work structurally and (almost) exclusively under the certificate of one client, that comes substantively close to the criteria the Belastingdienst uses to assess false self-employment (Wet DBA). Certification and tax self-employment status are two separate tests, but an arrangement that is convenient for one question can turn out to be precisely a risk for the other. Consider discussing this with a bookkeeper or lawyer before entering into a fixed "on behalf of" arrangement.

More about what BRL 100 precisely involves and how the audit works: What is BRL 100, and why does it affect your work order? and The BRL 100 annual check: what the auditor expects.

STEK: company certification, also for a sole proprietorship

STEK is a separate certification scheme for refrigeration engineering companies, with baseline requirements around quality, sustainability and safety, plus modules per application (F-gases, CO₂, heat pumps). Here too: work may only be carried out by a certified technician who is employed by a certified company. For a sole trader who works independently for third parties or wants to buy or sell F-gases themselves, an own STEK company certificate is therefore relevant. If you work exclusively for an already certified company under a written arrangement comparable to the one described above, that may be different, just as with BRL 100 — check this directly with STEK.

The difference between STEK and BRL 100, and which of the two (or both) is relevant for your work, is set out in STEK vs BRL 100 — what is the difference, and which one do you need?

Please note: from 1 September 2026, a renewed STEK company certificate is declared equivalent to BRL 100 — with a valid STEK certificate you then automatically meet the statutory BRL 100 requirement, and as a sole trader you no longer need to apply for both certificates separately. For existing certificate holders the transition arrangement is not yet finalised; check this directly with STEK or your certifying body.

Is a company certificate practically feasible as a sole trader?

BRL 100 and STEK are originally company certifications, with requirements around a quality system, administration, logbooks and a periodic surveillance audit (roughly every 2 years) — for a sole proprietorship that is a real time and cost burden alongside your hours on the road. Before you put time and money into this, it's worth getting clear for yourself:

• Do you work structurally, independently, for end customers, or almost exclusively as a subcontractor for one or a few certified companies?
• Is a written agreement possible that exempts you from having a company certificate of your own, and has that been confirmed by the certifying body itself?
• Does the investment weigh up against the kind of assignments you miss out on without a company certificate of your own?

Without a BRL 200 personal certificate you cannot work at all, regardless — that is not negotiable, and the risks of continuing to work without a valid certificate are not minor, see ILT fines for F-gases: risks without a valid certificate.

Insurance: not a legal obligation, but a real consideration

Unlike the certification obligation, liability insurance is not a legal requirement for a sole-trader installer in refrigeration engineering. In practice, however, a client, main contractor or trade association regularly does ask for it as a condition for an assignment or membership. Two types of insurance come up most often in this sector:

• Public liability insurance (AVB) — covers damage that you, your tools or your (any) product cause to others or to someone else's property. Think of a leak at a customer's premises or damage to an installation during work.
• Professional liability insurance (BAV) — covers financial loss suffered by a customer as a result of an error or negligence in the practice of your trade, for example incorrect advice or a missed fault that leads to consequential damage.

In addition, for a sole trader without staff it's worth looking into income protection insurance (AOV) — if you're unable to work, your revenue stops too — and into equipment or tool insurance for your measuring instruments and charging set. For concrete policy conditions and coverage amounts, the best approach is to compare quotes from different insurers or an insurance intermediary in the installation sector; this article will not fill that in for you, because coverage and premiums vary strongly per insurer and risk profile.

More background on what public liability insurance precisely covers in refrigeration engineering and what to pay attention to: Public liability insurance for refrigeration engineering companies

In short: the checklist for the sole trader

• BRL 200 personal certificate (category depending on your work): always mandatory, no exception.
• BRL 100 company certificate: in principle also mandatory for you yourself if you work independently for third parties; a possible exception for a written "on behalf of" agreement with a certified company has not been unambiguously confirmed — check this yourself with your certifying body.
• STEK company certificate: relevant if you independently carry out refrigeration engineering work for third parties or buy or sell F-gases yourself.
• KVK registration as a sole proprietorship, plus a clear picture of the Belastingdienst's self-employment criteria if you mainly work for one client.
• Public liability and/or professional liability insurance: not legally mandatory, but often a condition of assignment.
• AOV and equipment insurance: not a certification matter, but a practical consideration for a sole proprietorship.