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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

New Boiler Installation Costs 2026 (Updated)

01st October, 2026 Guides

New Boiler Installation Costs...

Understand what to budget for a boiler replacement, how conversions and relocation affect...

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Best compact combi boilers In 2026

01st October, 2026 Guides

Best compact combi boilers In...

Compare cupboard-friendly combi boilers by size, hot-water performance and installation sp...

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Best wall mounted air conditioning units

01st October, 2026 Guides

Best wall mounted air conditio...

Compare wall mounted air conditioners for quiet bedrooms, everyday comfort and lower upfro...

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The Best Smart Thermostats in the UK 2026

30th September, 2026 Guides

The Best Smart Thermostats in...

A smart thermostat can make a massive difference to your home and can be one of the best...

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Best Boiler Brands in the UK (2026) Top Manufacturers

30th September, 2026 Guides

Best Boiler Brands in the UK (...

Compare the UK's top boiler manufacturers for 2026.

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Boiler Diverter Valve: Symptoms, Repair and Replacement

30th September, 2026 Advice

Boiler Diverter Valve: Symptom...

A boiler diverter valve directs heat to your heating or hot water.

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What Is A System Boiler?

30th September, 2026 Advice

What Is A System Boiler?

A system boiler provides heating and stores hot water in a separate cylinder.

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Combi Boiler Replacement Cost

30th September, 2026 Guides

Combi Boiler Replacement Cost

Replacing your boiler can be a stressful and costly process. That’s why we have written th...

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How long does it take to fit a new boiler?

30th September, 2026 Guides

How long does it take to fit a...

Most boiler installations take between one and two days depending on your current setup an...

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Can A New Boiler Increase the Value of My House?

30th September, 2026 Advice

Can A New Boiler Increase the...

Have you considered a new boiler to increase the value of your home? We run through why th...

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Most Energy Efficient Boilers in 2026 (UK Guide)

30th September, 2026 Guides

Most Energy Efficient Boilers...

The efficiency of your boiler may not be something you pay much attention to, but is it co...

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What Size Combi Boiler Do I Need?

30th September, 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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