You’ve just had a new boiler fitted - job done, right? Not quite. Before your heating system can officially clock in, it needs to be commissioned.
Boiler commissioning is the final (but vital) step that ensures everything’s working safely, efficiently, and exactly as it should.
Skip it - or let someone rush it - and you could end up with higher bills, a voided warranty, or even a safety risk.
In this guide, we’ll explain what boiler commissioning involves, why it’s essential, and how to make sure it’s carried out properly.
🔑 Key Takeaways:
Boiler commissioning ensures your new system is installed safely and runs efficiently.
It involves a series of tests, checks, and system tweaks by a Gas Safe engineer.
Commissioning must be done to validate your boiler warranty.
You should receive a completed Benchmark Checklist as proof.
A poorly commissioned boiler can cost more to run and be less safe.
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What Is Boiler Commissioning?
Boiler commissioning is the final and critical step after a new boiler is installed.
Think of it as the engineer’s quality control check. It’s a full inspection to confirm your boiler is safe, correctly set up, and performing at its best.
It’s not a quick once-over. Commissioning includes in-depth tests and fine-tuning to make sure everything meets UK safety regulations and the manufacturer’s requirements.
Also known as boiler setup or post-installation checks, commissioning is a legal must-do - and it has to be carried out by a Gas Safe registered engineer.
If it’s skipped or rushed, you could end up with higher bills, a safety risk, and no valid warranty. Definitely not worth the gamble.
What Does Boiler Commissioning Involve?
When a Gas Safe engineer commissions your boiler, they don’t just switch it on and walk away. They follow a detailed process to make sure everything’s working as it should.
Here’s what’s typically included:
Checking gas pressure and flow – Confirms your boiler is getting the right amount of gas to run safely and efficiently.
Testing controls and safety devices – Makes sure thermostats, pressure relief valves, and other safety features are working properly.
Balancing radiators – Adjusts the system so every radiator heats evenly, eliminating cold spots.
Setting flow temperatures – Fine-tunes water temperature for maximum efficiency and comfort.
Completing the Benchmark Checklist – Officially logs all checks in your boiler’s logbook. This is essential for meeting warranty conditions.
These steps make sure your boiler is tailored to your home, compliant with UK regulations, and running at peak performance from day one.
Why Is Commissioning So Important?
Boiler commissioning isn’t just a formality - it’s essential for several key reasons:
Safety – A badly commissioned boiler could leak gas or produce carbon monoxide, a silent but deadly gas. Commissioning helps catch these risks before they become dangerous. [Learn more about gas safety.]
Efficiency – A properly set up boiler runs smarter, using less fuel and delivering consistent heating across your home.
Warranty protection – Most manufacturer warranties (typically 5–10 years) are only valid if commissioning has been done and logged correctly. No commissioning, no cover.
Building Regs compliance – UK Building Regulations require all new boilers to be commissioned to meet modern safety and efficiency standards. Read more about Building Regulations.
“Commissioning isn’t a nice-to-have - it’s a must. It’s the only way to know your boiler’s safe, efficient, and covered by warranty.” - Patrick Garner, Head of Installations at Heatable
Who Should Carry Out Boiler Commissioning?
Boiler commissioning must be carried out by a Gas Safe registered engineer. No exceptions.
Only a qualified professional has the training and legal certification to perform the checks needed to meet UK safety standards.
In most cases, the engineer who installs your boiler will also handle the commissioning - but don’t assume. It’s worth confirming this before the job begins.
To verify someone’s credentials, check the Gas Safe Register or ask to see their Gas Safe ID card. A legit engineer won’t hesitate to show you.
What Is the Benchmark Checklist?
The Benchmark Checklist is your boiler’s official logbook - a blue booklet (or digital version) provided by the manufacturer.
During commissioning, the engineer fills it out with key details about the installation, safety checks, and system settings. It’s then signed and dated to confirm everything’s been done by the book.
You should be given a copy when the job’s complete. Keep it safe - this checklist is your proof of proper commissioning, which you’ll need for warranty claims, future servicing, or even when selling your home.
Can I Check If My Boiler Was Commissioned Properly?
Absolutely - and you should.
Here’s how to confirm everything was done by the book:
Check the Benchmark Checklist – Your engineer should leave this behind, fully filled out and signed. No checklist? That’s a red flag.
Ask for commissioning records – Some installers also provide a separate commissioning certificate for your files.
Look for warning signs – If your boiler is making odd noises, your radiators are heating unevenly, or your energy bills are creeping up, it could point to poor commissioning.
If anything feels off, contact your installer or get a second opinion from a Gas Safe registered engineer. A good company won’t hesitate to confirm the details.
Always ask your installer to show you the completed benchmark Checklist before they leave.
No checklist, no warranty. It’s that simple. Taking this small step ensures your boiler is safe, efficient, and fully covered by its manufacturer's warranty.
Final Thoughts
Boiler commissioning might sound technical, but it’s a simple step that makes a big difference. It protects your home, your wallet, and your peace of mind.
By making sure your new boiler is tested and fine-tuned by a Gas Safe engineer, you’ll get safe, efficient heating - and avoid problems later.
Always ask for the completed Benchmark Checklist. It’s your proof that the job was done properly and your key to keeping that warranty valid.
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