Junior Developer

Energy Saving Trust; Greater London; Hybrid; GBP 27,000 - 34,000; Full time

Benefits offered by this job

Generous holiday 25 days + bank

Flexible working arrangements

Pension & life assurance

Enhanced family leave

Green travel perks

Professional development support

Yearly wellbeing allowance

Job summary

Energy Saving Trust is seeking a Junior Developer to help build and maintain the software behind our domestic energy modelling tools. You will contribute to the design, development, testing and maintenance of our energy modelling software, libraries and APIs using C# and .NET.

You’ll work under guidance from the Senior Energy Modelling Developer, tackle well-scoped tasks initially and gradually take ownership as your skills grow.

Qualifications

• Proficiency with C# and Microsoft .NET, demonstrated via work, study or projects.
• Experience with Git and Azure DevOps or similar platforms.
• Ability to write clear tests and documentation.

Responsibilities

• Develop C# and .NET software from specifications and research.
• Maintain and improve libraries, services and APIs.
• Include unit tests and automated testing; support code reviews.
• Use Git and Azure DevOps for planning, development and release.
• Collaborate with analysts and energy modellers on modelling software.

Skills

C# & .NET

Visual Studio

Git

Azure DevOps

Analytical thinking

Tools

Visual Studio

Git

Azure DevOps

Job description

Up To £30,500 Per Annum (depending On Experience)

The role

Looking for a junior developer role where you can keep learning and contribute to work with a clear purpose? Join Energy Saving Trust and help develop the software behind our domestic energy modelling tools.

Up To £30,500 Per Annum (depending On Experience)

The role

Looking for a junior developer role where you can keep learning and contribute to work with a clear purpose? Join Energy Saving Trust and help develop the software behind our domestic energy modelling tools.

You’ll use C# and Microsoft .NET to turn research, calculations and technical specifications into reliable, maintainable code. Your work will support the digital products and services that underpin our efforts to improve energy efficiency and address the climate emergency.

Whether you’ve developed your coding skills through employment, education, personal projects or another demonstrable route, we’re interested in what you can bring, and how you want to grow.

As a Junior Developer, you’ll contribute to the design, development, testing and maintenance of our energy modelling software, libraries and APIs.

This is an opportunity to combine software development with analytical problem-solving, working on the calculations and logic behind our digital services. You’ll improve existing code, develop new features and build your understanding of how energy use in homes is modelled.

You won’t be expected to know everything from day one. With technical direction, code reviews and coaching from our Senior Energy Modelling Developer, you’ll start with well-scoped tasks and gradually take ownership of larger pieces of work as your skills and confidence develop.

The team

You’ll join our Engineering team, working closely with developers, analysts and energy modellers. Together, you’ll translate specialist knowledge into practical software solutions.

Sharing feedback, asking questions and learning from colleagues will be part of your everyday work. You’ll contribute your own ideas while developing your knowledge of software engineering and domestic energy modelling.

What You Will Do

• Develop C# and .NET software that turns energy modelling specifications, research and algorithms into clear, efficient code.
• Maintain and improve libraries, services and APIs, investigating bugs and helping make our software more reliable.
• Build quality into your work through unit tests, automated testing, code reviews and clear technical documentation.
• Use Git and Azure DevOps to manage code and contribute to planning, development and release activities.
• Work with developers, analysts and energy modellers, building your understanding of domestic energy modelling and contributing to improvements in how we work.

What You Will Bring

• A good working knowledge of C# and Microsoft .NET, gained through work, study, personal projects or another demonstrable route, alongside experience with tools such as Visual Studio.
• An understanding of object-oriented programming, clean code and testing basics, plus experience using Git and familiarity with Azure DevOps or a comparable platform.
• Strong analytical and problem-solving skills, with confidence working through numerical concepts and logical challenges.
• Clear communication and organisational skills, including the ability to explain your thinking, manage agreed priorities and recognise when to ask for support.
• A willingness to learn, seek feedback and develop your software engineering and energy modelling knowledge, while contributing to an inclusive and professional team.

Experience with Python, SQL, Agile development or AI-assisted development tools would be useful, as would an interest in sustainability, energy systems or data-driven research. These are desirable, not essential.

Who We Are

Energy Saving Trust is a leading and trusted organisation, dedicated to promoting energy efficiency, low carbon transport and sustainable energy use. We aim to address the climate emergency and deliver the wider benefits of clean energy as we transition to net zero.

At Energy Saving Trust we don’t just offer jobs – we offer careers. For our people, being part of the effort to address the climate emergency makes working for us truly meaningful and rewarding.

Work where you thrive

At Energy Saving Trust, flexibility isn’t just a policy, it’s how we work. Most of our roles can be done remotely, and many of our people choose to work from home full-time. Prefer an office environment? We have welcoming spaces in London, Edinburgh, Belfast, Cardiff and Hadleigh for those who want to connect in person.

We’ll Support You With

• Generous holiday (25 days + bank holidays + extra Christmas leave)
• True flexibility in how and where you work (subject to role requirements)
• Strong pension & life assurance
• Enhanced family leave
• Green travel perks (EV scheme, cycle to work)
• Professional development support
• Yearly wellbeing allowance

These are just some of the benefits we offer.

Want to know more about how we make flexibility real? Check out our Benefits and Culture page

Reasonable adjustments:

We want to ensure that our recruitment process is inclusive of and accessible for, everyone.

If you think you may need additional support or reasonable adjustments made to any part of the recruitment process, please get in touch with [e-mail] or call reception on [phone]. We will do our very best to support you.

Diversity and inclusion

Energy Saving Trust is committed to creating a diverse, inclusive and equitable workplace where everyone can be themselves, with support to be their best.

We strongly encourage applicants from a wide range of backgrounds and with different identities and experiences to apply for roles with Energy Saving Trust.

We are a Disability Confident Committed employer and we ringfence a minimum number of interview slots for candidates who apply via the Disability Confident scheme and meet the criteria for a role. Find out more here.

You can find out more about our commitment to diversity and inclusion here.

Please note, that we are unable to provide visa sponsorship for this post. To apply for this post, you must be able to demonstrate your eligibility to work in the UK