The Money Saving Boiler Challenge for Nesta

A quick and easy tool that reduced household emissions by 37,000 tns and provided energy savings of £20m.

Project overview

Nesta is the UK’s innovation agency for social good. Designed to tackle society’s biggest challenges and to deliver impact at scale. Nowhere is this purpose better demonstrated than in the Money Saving Boiler Challenge. The Energy Awards 2023 and PRCA Consumer Award winning campaign tackled two of the most pressing issues of our day; the cost of living crisis and climate change.

Research showed 16% of UK carbon emissions come from household heating, the average gas boiler emits more emissions in a year than taking seven transatlantic flights. With an immediate need for action, and to make the most efficient use of existing heating systems Nesta explored small yet effective improvements.

We created a website to support the tool developed by Nesta. The website provides a step-by-step guide on how users can make a simple change to their boiler settings to reduce carbon emissions and save money.

Our goal was to reach one million households and showcase the impact of collective action. However, the campaign surpassed our expectations with an estimated 3.1 million households taking part. As a result, there were nationwide savings of an estimated £300 million and a reduction of 500,000 tonnes in CO2 emissions.

The Money Saving Boiler Challenge for Nesta

The approach

With only nine weeks to turn the project around, we were excited to pull up our sleeves and get the site ready in time for heating season!

Our objective was to create a website that was easy to navigate, guiding users step-by-step through the Nesta tool, demonstrating how to adjust boiler settings and encouraging users to share the campaign with others.

To ensure the web tool would meet the brief of a usable, trackable and engaging experience, Nesta invited over 3,500 users of an energy advice app to experiment and test:

  • Would the web tool result in more households turning down their combi-boiler flow temperature?
  • For the households that took part were they using less energy?
  • With a reduced flow temperature were the homes still warm and comfortable during the cold winter months?

With the positive initial results from the trial, we used this as input into our user experience and user interface design, we worked together to create a user-friendly website to host Nesta’s tool.

As a nationwide consumer-facing campaign, we needed to ensure the site was resilient and accessible to a wide audience. Importantly not everyone is comfortable making changes to their boiler and there was a risk that users could feel overwhelmed and drop off mid-journey. As the advice was specifically for combi boilers, it also needed to be clear to users, who may not initially know what type of boiler they owned. To help give the user some extra support, we designed the walkthrough with visual references that they could click for personalised instructions. We also identified that users were likely to open the website on their phone while standing in front of the boiler, so the website was designed to be mobile-first as well as meet high accessibility standards.

Once we were confident about the structure of the tool, we needed to encourage users to start the process. The landing page was intentionally simple and lightweight, using solid colours rather than lots of imagery to draw the user’s attention to this important call to action at key points on the page. The supporting content pages such as Blog, FAQ and Evidence demonstrate the impact of the boiler setting change for the more inquisitive users, before steering them back to the landing page to complete the walkthrough. Once the user has completed the steps and optimised their boiler, they can easily click to share via a button which automatically populates a social post with a link and a message to be shared with their network.

Though the action itself was quick and easy to take, Nesta understood that the campaign message was potentially a big ask for users, to make a change to expensive equipment that controls heating in their homes and to share the campaign with others to encourage collective action.

To keep the audience engaged at every step, we made the financial and environmental benefits clear from the start. To create a collective sense of achievement, we also introduced a live totaliser to the homepage, helping to measure and show instant results. When users come to the website, they can immediately see how many boilers have been optimised, what the current campaign target is and how they can join the movement for a more cost-effective and environmentally friendly home.

The Money Saving Boiler Challenge for Nesta

The results

In 2023 the project won the Energy Awards 2023 Campaign of the Year and PRCA’s Consumer Award. The campaign has reached over 31 million of the UK adult population, with 9.7 million people in the original target audience

Between October 2022 and March 2023, more than 214,000 people used the online tool and told Nesta they had turned down their boiler flow temperature. It is estimated this saved a collective of over £20 million in energy bills and 37,000 tonnes of CO2 per year.

We also know that Nesta’s radio campaign, alongside Nesta and others’ influence on government and energy companies, increased the campaign’s reach and advice through other channels, resulting in a much greater impact.

Nesta commissioned pre, mid and post-campaign tracking through an external campaign tracking agency which surveyed a representative sample of more than 2,000 GB adults in each survey. In early October 2022, 21% of people said they had lowered their boiler flow temperature in the past. This rose to 32% in March 2023.

We estimate this equates to, approximately 3.1 million households turning down their boiler flow, saving an estimated 500,000 tonnes in CO2 emissions and a total of £300 million in household savings.

Although the campaign itself has now finished the work continues to have an impact and The Money Saving Boiler Saving Challenge is still live. The site is working hard on increasing awareness and making it easy for households to optimise boiler settings, helping them to save money and reduce their carbon footprint. Nesta believes with the continued impact this work could save several billion pounds over the next 5 to 10 years.

The website was also recommended by Martin Lewis on primetime television as a way to help save UK households money.

“Working with Pixeled Eggs on our first consumer-facing campaign website was a really collaborative and well-run process. The team are hugely knowledgeable and were able to develop a site that seamlessly takes users through the journey and that has gone on to be really well received and high performing. The team at Pixeled Eggs were responsive, creative and added real value throughout the process.”
Elin Price, Campaigns Manager at Nesta

Climate conscious website design

As a sustainable campaign designed to reduce carbon emissions, we needed to ensure the site was as efficient as possible. Taking this into consideration we built the tool to be lightweight to reduce the carbon footprint, whilst being built to last to give longevity and maximum value. The web tool continues to be of use and benefit to the general public, providing continued guidance and support to users.

We achieved this by efficient use of imagery and utilising design-led assets, a clean and efficient layout and creative design, that would reduce and keep page weights to a minimum. This is further supported by streamlined navigation and careful consideration of fonts. The site contains no videos and uses step-by-step guides, FAQs and blogs to provide key information to users. With further build and development infrastructure to minify code and reduce server requests.


Over 3.1 million households turned down their boiler flow.


An estimated reduction in CO2 emissions by 500,000 tonnes.

Money saving:

An estimated £300 million saved as a result of the campaign.

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