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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

Best Combi Boilers In 2026

11th June, 2026 Guides

Best Combi Boilers In 2026

Compare the best combi boilers in 2026, including Worcester Bosch, Alpha, Vaillant and Vie...

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Best Boiler Brands in the UK (2026) Top Manufacturers

11th June, 2026 Guides

Best Boiler Brands in the UK (...

Choosing the best boiler brand comes down to reliability, warranty support, efficiency, an...

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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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What Size Combi Boiler Do I Need?

11th June, 2026 Advice

What Size Combi Boiler Do I Ne...

Find out whether the size of your combi boiler will make any difference to its capabilitie...

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How much does a new boiler cost in the UK

11th June, 2026 Guides

How much does a new boiler cos...

Based on data from over 7000 boiler installations completed by iHeat in the past 12 months...

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Best Compact Combi Boilers In 2026

11th June, 2026 Guides

Best Compact Combi Boilers In...

A simple guide to the smallest combi boilers that fit inside kitchen cupboards and tight s...

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Is Air Conditioning Allowed in New-Build Homes?

04th June, 2026 Guides

Is Air Conditioning Allowed in...

Yes, air conditioning is usually allowed in new-build homes, although property-specific re...

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Retrofitting Air Conditioning in Older Homes: What to Consider

03rd June, 2026 Guides

Retrofitting Air Conditioning...

Yes, most older homes can have air conditioning installed, but factors such as insulation,...

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Boiler Losing Pressure: Causes, Fixes & When to Call an Engineer (Gas Safe Guide)

01st June, 2026 Advice

Boiler Losing Pressure: Causes...

If your boiler keeps losing pressure, the cause is usually a leak, trapped air, or a fault...

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Why is My Air Conditioner Blowing Warm Air Instead of Cool?

29th May, 2026 Advice

Why is My Air Conditioner Blow...

If an air conditioner is blowing warm air instead of cool air, it is often caused by dirty...

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Why Is My Air Conditioner Making Noise?

29th May, 2026 Guides

Why Is My Air Conditioner Maki...

Air conditioners naturally make some noise while running, but unusual sounds such as rattl...

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