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Stephen Day

Gas Safe Engineer at iHeat

Stephen Day is a Gas Safe registered and FGAS certified engineer with over 20 years of hands-on experience in the heating, cooling, and renewable energy industry, specialising in boiler installations, air conditioning, and heat pump systems.

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About Stephen Day

Stephen Day is a Gas Safe registered and FGAS certified engineer with over 20 years of hands-on experience in the heating, cooling and renewable energy industry.

Throughout his career, Stephen has designed, installed and maintained thousands of systems across homes and businesses in the UK. His background on the tools, combined with his directorship role at iHeat, gives him a rare understanding of both the technical and operational sides of the industry.

He has helped to secure Which? Trusted Trader accreditation all with a focus on delivering great service and long-term value for customers. He also writes for the iHeat blog, sharing practical advice and explaining heating topics in plain, helpful language.

Stephen continues to stay up to date with the latest heating technologies, building regulations and low-carbon innovations.

Gas Safe ID: 5910722

Expertise

  • Boiler systems and installation
  • Heat pumps and hybrid heating systems
  • Gas safety and compliance
  • System design
  • Renewable and low-carbon technologies
  • Technical training


Articles by Stephen Day are reviewed by iHeat’s technical team for accuracy and reliability.

Stephen Day's latest articles

What Size Air Source Heat Pump Do You Need?

22nd June, 2026 Guides

What Size Air Source Heat Pump...

Air source heat pumps (ASHP) are popular for providing efficient heating solutions. These...

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How to Repressurise a Baxi Boiler

19th June, 2026 Guides

How to Repressurise a Baxi Boi...

Repressurising a Baxi boiler means restoring the correct water pressure inside the boiler...

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Repressurise Vaillant Boiler

19th June, 2026 Guides

Repressurise Vaillant Boiler

Low pressure in a Vaillant boiler is a common issue for many UK households. It affects com...

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Worcester Bosch Boiler Pressure - UK Mega Guide

19th June, 2026 Guides

Worcester Bosch Boiler Pressur...

Worcester boiler pressure should usually sit around 1 to 1.5 bar when the system is cold

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Pressure Release Valve Boiler

19th June, 2026 Guides

Pressure Release Valve Boiler

A pressure release valve (PRV) on a boiler is a critical safety component ensuring that th...

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What Is An Expansion Vessel?

19th June, 2026 Guides

What Is An Expansion Vessel?

An expansion vessel is an essential component of a modern boiler system, serving a pivotal...

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Boiler Losing Pressure: Causes, Fixes & What To Do Next

19th June, 2026 Advice

Boiler Losing Pressure: Causes...

Repeated pressure loss usually points to a leak, faulty component, or another issue within...

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Boiler Not Working? Most Common Problems (And Fixes)

16th June, 2026 Advice

Boiler Not Working? Most Commo...

A complete guide to getting that boiler working again and some common fault codes and how...

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Bosch Climate 3000i Air Con Review

16th June, 2026 Reviews

Bosch Climate 3000i Air Con Re...

After an in-depth look at the Bosch Climate 3000i air conditioning system, we've broken do...

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Air Conditioning for Homes With High Ceilings: What to Consider

12th June, 2026 Advice

Air Conditioning for Homes Wit...

Air conditioning can work well in homes with high ceilings, but room volume, airflow and u...

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Combi Boilers - Advantages And Disadvantages

11th June, 2026 Comparisons

Combi Boilers - Advantages And...

Combi boilers are by far the most popular type of home heating system in the UK, and with...

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Condensing Boilers vs Combi Boilers

11th June, 2026 Comparisons

Condensing Boilers vs Combi Bo...

In this guide, we’re going to be explaining what each of these terms mean so you know exac...

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