Your Guide to Unvented Hot Water Certification (G3 Explained)
If you’re a plumber or heating engineer looking to install or maintain unvented hot water systems, you’ve likely asked: Do I need a qualification? The answer is yes — and it’s crucial for safety, compliance, and protecting your business.
This guide explains why the Unvented Hot Water qualification (G3 Building Regulations) is essential and what it covers.
What is an Unvented Hot Water System?
Unvented systems store hot water under pressure, providing strong flow rates for showers, baths, and multiple outlets. Unlike traditional vented systems, they don’t rely on a cold-water tank in the loft. Typical installations include:
Working without the correct certification could breach building regulations and invalidate manufacturer warranties. It also increases safety risks, such as overpressure or even explosion, and could lead to legal action if any faults cause damage or injury.
What Does the Unvented Qualification Cover?
The course is designed for plumbers and heating engineers. It covers:
Most training courses run over one day and result in a certificate valid for 5 years.
What Are the Benefits of Getting Qualified?
Completing the Unvented Hot Water course allows you to legally self-certify your work, giving you the freedom to install and maintain systems without relying on a third party. It also opens up new job opportunities and services you can offer, helping to grow your business. Being fully qualified increases customer trust and boosts your professional credibility, while reducing the risk of costly mistakes or call-backs.
How Long Does It Take to Get Unvented Hot Water Certified?
The Unvented Hot Water Certification (G3 qualification) typically takes one day to complete. The course combines classroom-based theory with practical assessments to ensure you fully understand system installation, maintenance, and safety.
At the end of the day, you’ll complete a written assessment and practical tasks. Successful candidates receive their certificate, which is valid for 5 years.
What Will You Learn on the Unvented Hot Water Course?
The course is designed to give plumbers and heating engineers the knowledge and skills needed to work safely and legally on unvented systems. You’ll cover:
- The principles of unvented hot water systems and how they operate
- G3 Building Regulations and legal requirements for installation and maintenance
- Safety devices, pressure relief valves, and system controls
- Installation best practices, including siting and pipework considerations
- Fault-finding, servicing, and maintenance procedures
- How to identify potential risks like overpressure and contamination
- Certification and notification requirements for compliance
By the end of the course, you’ll be able to confidently install, commission, and maintain unvented hot water cylinders — and legally self-certify your work.
At T-Gas Northern in Thirsk, we specialise in helping plumbers and heating engineers gain the qualifications they need to expand their skills and services. Our experienced trainers guide you through every part of the Unvented Hot Water (G3) certification — making the process straightforward and practical.
✔ Fully accredited Unvented (G3) training
✔ Small class sizes for personal support
✔ Hands-on practical assessments
✔ Flexible course dates to suit your schedule
We’ll also talk you through what happens next — from certification to legally self-certifying your work — so you leave confident and ready to take on unvented installations.
