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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

The best air source heat pumps available in 2026

01st October, 2026 Advice

The best air source heat pumps...

Compare current heat pump ranges, understand the differences that matter and choose a syst...

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Viessmann Vitodens - A Guide to the Range

01st October, 2026 Reviews

Viessmann Vitodens - A Guide t...

Compare the current Viessmann Vitodens range and find the right boiler for your home.

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Gas boiler vs electric boiler: which is the best?

01st October, 2026 Comparisons

Gas boiler vs electric boiler:...

The cost of running an electric boiler can be high, especially if you live in the UK. Let'...

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Heat Pump Maintenance

01st October, 2026 Guides

Heat Pump Maintenance

Understand the checks you can do at home, what a professional service should include and h...

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How to choose the right heat pump size

01st October, 2026 Guides

How to choose the right heat p...

Learn how heat loss, radiators and hot-water needs determine the right heat pump size and...

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What is a boiler flue and how do I find it?

01st October, 2026 Advice

What is a boiler flue and how...

A boiler flue carries combustion gases outside. Here is how to identify yours and when to...

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What Are Biomass Boilers And Heating Systems?

01st October, 2026 Advice

What Are Biomass Boilers And H...

Biomass is an environmentally considerate and renewable energy source, generated from the...

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Viessmann F2 Fault

01st October, 2026 Guides

Viessmann F2 Fault

The Viessmann F2 fault means the boiler's temperature limiter has responded, placing the b...

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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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