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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

Navien NCB 300 Boiler Review

05th January, 2026 Reviews

Navien NCB 300 Boiler Review

Unlocking the Efficiency and Value of the Navien NCB 300 Boiler: A Comprehensive Guide for...

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Best Electric Combi Boilers (Electric-Only Guide)

05th January, 2026 Guides

Best Electric Combi Boilers (E...

The best electric combi boilers in 2026 include models from Electric Heating Company, Heat...

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UPDATED: Heat Pump Planning Permission: Do I Need It for My Home?

05th January, 2026 Guides

UPDATED: Heat Pump Planning Pe...

Heat pumps generally don't require planning permission in the UK, thanks to permitted deve...

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Oil Boiler Ban

05th January, 2026 Guides

Oil Boiler Ban

As preparation steps up for the transition from oil boilers, homeowners confront a multifa...

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Best Home EV Chargers

05th January, 2026 Guides

Best Home EV Chargers

Electric vehicles (EVs) have transformed the way we think about personal transportation, n...

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Best UK Boiler Cover 2026

05th January, 2026 Guides

Best UK Boiler Cover 2026

A broken boiler often means a cold house with no access to heating or hot water, leaving m...

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The Best Budget Boiler in 2026

19th December, 2025 Guides

The Best Budget Boiler in 2026

The best budget boilers are Ideal, Alpha, Baxi, Worcester Bosch and Vaillant models, compa...

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What is an Airing Cupboard?

19th December, 2025 Guides

What is an Airing Cupboard?

An airing cupboard is a heated storage space that uses warmth from a hot water cylinder or...

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Worcester Bosch vs Vaillant Boilers - Which is Better?

19th December, 2025 Advice

Worcester Bosch vs Vaillant Bo...

A clear comparison of Worcester Bosch and Vaillant Boilers and why Worcester Bosch is ofte...

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Combi Boiler Pressure: What It Should Be And How To Fix Issues

12th December, 2025 Guides

Combi Boiler Pressure: What It...

A combi boiler should be around 1.0 to 1.5 bar when cold and up to about 2.0 bar when hot.

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How To Bleed A Radiator

12th December, 2025 Advice

How To Bleed A Radiator

You bleed a radiator by turning off the heating, opening the bleed valve and releasing tra...

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How To Fix Sludge in Radiators

11th December, 2025 Advice

How To Fix Sludge in Radiators

If you’ve noticed your energy bills rising recently, this could be down to a number of rea...

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