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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 Shower for Combi Boiler

18th December, 2025 Guides

Best Shower for Combi Boiler

A combination boiler, commonly known as a combi boiler, is an advanced heating unit that p...

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Which Boiler is Best for a 3 Bedroom Home?

18th December, 2025 Guides

Which Boiler is Best for a 3 B...

Picking the correct size combi boiler for your home

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Best Heating for Off-Grid Homes

18th December, 2025 Guides

Best Heating for Off-Grid Home...

Homes that are not connected to the mains gas grid in the UK need alternative heating syst...

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Vaillant Boiler F22

12th December, 2025 Guides

Vaillant Boiler F22

The Vaillant F22 fault means your boiler pressure is too low and needs topping up.

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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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Boiler Losing Pressure, What Should You Do (How To Fix)

11th December, 2025 Advice

Boiler Losing Pressure, What S...

A boiler losing pressure is usually caused by a leak, trapped air, or a faulty valve - her...

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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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Different Types Of Radiator Bleed Valves/Knobs Explained

11th December, 2025 Guides

Different Types Of Radiator Bl...

Radiator dials, often referred to as bleed valves or knobs, are crucial for managing the p...

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Radiators Not Heating Up: How to Fix?

11th December, 2025 Guides

Radiators Not Heating Up: How...

If your radiators aren’t heating up, it’s usually caused by trapped air, sludge, or a boil...

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What Temperature Should My Boiler Be Set At In Winter?

09th December, 2025 Guides

What Temperature Should My Boi...

Most homes stay warm in winter with heating set at 60 to 70°C and hot water at 50 to 55°C.

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Central Heating System

09th December, 2025 Guides

Central Heating System

A simple breakdown of the main central heating systems in UK homes and how to decide which...

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