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Boost Power (OVO Energy)

Creating an innovative scheme to help pay-as-you-go energy customers save for winter



Boost Power needed to improve customer retention but they didn't know why customers were leaving. I led a discovery phase to help the team understand our customers needs. We learnt that a big pain point was trying to cover the costs of energy in winter. Through faciliating collaborative design sessions, we quickly developed concepts and validated them through user testing before launching the 'Winter Wallet', an innovative savings scheme that uses insights from behavioural economics to help customers build up savings for winter. This delighted customers and significantly improved customer retention. I evolved the scheme the following year to quadruple its impact.




OVO Energy launched Boost Power, a Pay As You Go (PAYG) energy brand, in 2017. With PAYG, you need to keep your energy account topped up with credit to ‘keep the lights on’. Boost’s main product, ‘Smart PAYG+’, lets customers do this through a smartphone app linked to their smart meter.

PAYG customers are free to change suppliers whenever they want without paying exit fees. And they were leaving us in droves. The team had lots of ideas for improvements but as we’d never done in-depth customer research, it was impossible to judge if these ideas would solve real customer problems. We needed to take a step back to identify the problems PAYG users actually face. And then agree which problems to go after to improve customer retention.




To better understand customers’ pain points, I reviewed customer feedback from social media and our leavers survey. Many complained about the cost of their energy, particularly in the winter, when they might fork out five times as much than in the summer.

Facebook complaint with screenshot showing high energy costs in winter
Complaint on social media about energy costs in winter


The team had formed the following assumption to explain why people leave:

Customers think they’re paying more in the winter because we’ve put our prices up (we hadn’t) rather than understanding that they’re using more energy.

I was keen to use the research to help get to the bottom of this.

Lots of our customers are lower income mums and as most of the negative feedback was around energy costs, I was keen to explore:

  1. What challenges do these mums face managing a tight budget?
  2. Where does managing their energy costs sit in this broader context of managing their money?
diagram showing broader context beyond managing energy, such as how they manage money more generally
To really understand our customers, we needed to understand the broader context



I believed that interviewing PAYG users in their homes would help us build rapport, making them more comfortable talking about the sensitive subject of money. We’d also get a better sense as to how they lived their lives and what they really spend their money on — reducing any social desirability bias we may have got through interviews in a neutral location.

With a limited research budget, we decided to run a pilot study to help inform the interview guide for the more costly home visits. We ran online interviews through usertesting.com with PAYG users, experimenting with different questions as we went along.

At Boost, we strive to have a multidisciplinary team of problem solvers. It was therefore key that we involved different team members, from developers to copywriters, right from the beginning, to build a shared understanding around the customers’ problems.

I ran a workshop where we watched the usertesting.com interviews as a team and captured observations as we went, which we then grouped into pain points, behaviours, attitudes and understanding and goals.

photo of post-its of user behaviour grouped into themes


Through this activity, some key insights emerged.

  1. Many had negative experiences with other payment methods where they’ve been hit with a huge bill out of the blue. They value PAYG as it allows them to stay in control of their spend.
  2. Generally they top up weekly, so they’re hyper aware of how much they’re spending on energy.
  3. People understood that they’re paying more in winter because they’re using more to heat their home. This contradicted our previously held assumption that people were complaining about higher costs in the winter because they didn’t understand the relationship between usage and costs.
  4. It’s a real struggle to cover the high energy cost in winter There are serious consequences to running out of energy credit. Being disconnected is very distressing.

These insights allowed me and my research partner to create a more focussed discussion guide for the home visits.


I conducted interviews with financially struggling mums around the country. This included our customers and competitor’s customers so we could learn how they’d solved problems that our customers faced.

I made sure that our developers attended the interviews so they could gain first-hand exposure to the insights, which is a lot more powerful than hearing about them in research playbacks.


In parallel to running the home interviews, I ran phone interviews with customers who’d downgraded from our main PAYG+ product. I stayed away from the topic of how they manage their money as I felt they were unlikely to open up as much over the phone. Instead, I focussed on why they were unhappy with the PAYG+ product.


Following the interviews, I ran a workshop with the team to analyse the interview transcripts (which I’d written up in-between interviews).

photo of people arraging post-its
Developers sharing their observations from analysing the interview transcripts


We learnt that interviewees really struggled to save money generally and with no reserves, paying for energy in the winter was using most of their budget.

Some people had strategies like topping up more than they needed in the warmer months, building up a surplus, which would ease the pain in the winter. Not everyone was that savvy. We heard stories about others with no savings who had to choose between heating and eating.

Based on these insights, we came up with an alternative interpretation of the social media comments mentioned earlier.

Customers think they’re paying more in the winter because we’ve put our prices up (we hadn’t) rather than understanding that they’re using more energy.

Customers are venting their frustration because they’re really struggling with the winter energy costs.


We agreed to tackle this and to help focus the creative exercises, I reframed this as:


Help customers save money in the warmer months so they can cope better with energy costs in the colder months




Over the last half century, there’s been a growing body of psychology and behavioural economics research that’s helping us understand why we behave the way we do. To be successful, we’d need to help our customers change their behaviour (start saving for the winter) so it made sense to build our solutions on top of existing evidence of what works.

In our workshop the next day, I presented some of the relevant behaviour change research and then I facilitated a ‘design studio’. To avoid groupthink, where everyone’s thinking about solving the problem in one way, the design studio format allowed the team to generate a variety of ideas independently, receive critique from the group and then iterate on those ideas.

photo of team member sketching ideas on paper
Team member sketching ideas during design studio


photo of team members at board looking at sketches with post-it comments placed on top
Team reviewing ideas from design studio


With the next round of interviews booked in, we had the opportunity to test these concepts so I quickly refined the most promising ideas into a basic prototype. We had 2 ways of helping people cope better with the additional winter energy costs:

1. Energy Savings Pot

You set a savings target and decide what percentage of each future energy top up you make should be transferred to a separate savings pot, which you’d be able to use in the winter.

screenshots of the savings pot concept


2. Scheduled Top-ups

You see a breakdown of your predicted energy usage across the next 6 months. You can setup a scheduled top up into your energy account e.g. £25 a week. This would be more than you’re actually using in the warmer months so credit would build up on your energy account, which you’d rely on in the winter months when your weekly payments on their own wouldn’t cover your energy usage.

screenshots of the scheduled payments concept



I tested the concepts in one-to-one interviews with financially struggling mums held in our office. The idea of a separate savings pot got people really excited.

“I think people would be stupid if they didn’t take it up.... ‘It’s no different to saving for Christmas”

Financially struggling mum


In contrast, the scheduled payments concept got a mixed reaction. Some felt like they’d lose one of the key benefits of being PAYG — the ability to track of how much energy they were using each week.

Something that we’d not previously considered was people’s maths literacy. The testers who struggled with maths, found the percentages confusing with the savings pot concept, and the graphs confusing with the scheduled payments concept.

We also explored different reward mechanics to incentive people to keep saving. Not surprisingly, the idea of rewarding people with a fixed bonus if they hit their target was also very positively received.


Through further user testing and peer feedback, I refined how you contribute to your savings pot. I ditched the fixed percentage idea, which was over complicated and did not suit those who are not maths literate.

We still wanted to keep the incidental nature of contributing to your savings pot - as in, if you’re topping up your energy account weekly, then that’s a perfect opportunity to encourage people to top up their savings pot.

With the next iteration, once you’ve chosen how much to top up your energy account, you’re asked to contribute to your savings pot. We added instant feedback, showing how close you are to reaching your savings target based on the amount you’ve chosen. And to reduce decision paralysis, we set a £20 default amount (spoiler alert: this came back to bite us when we launched).

screens showing revised designs of savings concept

Revised designs for savings pot concept




As summer was coming to a close, we knew we had to launch the most basic version of the savings pot straight away so people still had time to build up savings before winter. We launched the initiative, which we rebranded the Winter Wallet, in the last week of August. The key features of the Winter Wallet were:

  1. Choose a savings target and if you hit this by the end of the savings period, you’ll get a 5% bonus e.g. you’d get £7.50 bonus if you hit a target of £150. Applying the learnings from the concept testing, we converted the percentages into concrete amounts to make it easy to understand.
  2. Add money to your Winter Wallet once you’ve decided how much you want to top up your energy account.
  3. You can’t access your savings until the end of the savings period (unless you called up). We decided on this because
    a) we didn’t have time to build the functionality needed
    b) we learnt from our interviews that our customers have self-control issues when it comes to saving money. Understandably, when managing a tight budget, it’s extremely challenging to save for the future when you’ve got more immediate needs to take care of. I believed that by adding this friction, we’d remove the temptation of taking out your savings too early and increase your chance of successfully saving for the winter, when you need it most. This approach demonstrates how we prioritised what users need over what they may say they want.


We’d hypothesised that helping customers save money for the winter using the Winter Wallet, would lead to happy customers who want to stay with us for longer.

Based on this hypothesis, we created 2 key performance indicators (KPIs) that we’d track and try to optimise:

  1. 20,000 customers opting into the scheme
  2. 30% customers hitting their target (as summer was coming to an end, we knew this would be challenging)

From tracking the opt-in rate in the first week, we could see that we were unlikely to hit that target so we needed to take action quickly.


I introduced a variety of feedback mechanisms to learn quickly what customers were doing and why.

diagram showing different feedback mechanisms to understand the what and the why

Launching our on-site survey helped us learn whether customers who’d visited the Winter Wallet landing page intended to sign up to it in the future and if not, what were the barriers to doing so. Creating a conversion funnel highlighted where people were dropping out of the sign up flow.

diagram of conversion funnel
Conversion funnel showing where people where dropping out




I devised a series of A/B experiments to optimise the numbers opting in and hitting their target.

Experiments to drive opt-ins

Were customers seeing the homepage promo but didn’t have the motivation to click through?

Returning to the behavioural economics literature allowed me to build on learnings from similar experiments. For example, an experiment ran by the ‘Common Cents Lab’ found that using ‘claim your discount’ rather than ‘sign up for a discount’ had successfully increased open rates and click through rates in an email experiment. The authors of the experiment reasoned that ‘claim’ signals a sense of ownership which triggers feelings of loss aversion. Loss aversion is the tendency to prefer avoiding losses to acquiring equivalent gains. The word also trigger the scarcity bias (we unconsciously assume things that are scarce are more valuable than things that are abundant). We tried changing the language to ‘Claim your 5% savings bonus...With our Winter Wallet’ which led to a massive 56% improvement in sign up rates.

original version of screen compared with variations tested
A/B test of different call-to-actions


Were users even paying attention to the homepage promo?

We experimented with making the promo stand out more by changing its background colour. This created more contrast between the now blue promo and the rest of the page. This resulted in a 22% improvement in sign-ups to the Winter Wallet.

original version of screen compared with bluevariation
A/B test of different colour promo


Or were they intrigued by the Winter Wallet promo but needed to focus on the more immediate goal of topping up their energy?

Hardly anyone was clicking the promos we had throughout the top up flow so I suggested we include a message once they had completed their top up task, with an animation to draw extra attention to it.

This created a huge spike in sign ups.

screenshot showing thank you page with Winter Wallet promo
Effective Winter Wallet promo after user has topped up energy account


Too frictionless

There’s a danger when you’re trying to optimise for a certain behaviour that you make the action too frictionless. Customers who sped through the top flow, repeatedly clicking on the Confirm button, accidentally added the default £20 contribution to their Winter Wallet. We learnt through feedback from the customer services team that this was driving calls from upset customers who couldn’t afford to lock away that money in their Winter Wallet.

Why didn’t we pick this up through the user testing we performed pre-launch?

In a test environment, it’s difficult to recreate real-life scenarios — someone desperate to top up their energy (possibly about to be disconnected), where English is their second language. With user testing, these biases can creep in without you realising. For us, the fact that they were using usertesting.com meant that their reading level was high enough to follow the onscreen instructions. Also, user testers tend to spend more time working through a prototype than they would in reality.

Fortunately, we had the right feedback mechanisms in place to quickly capture and address these issues. In this case, I removed any default so the user had to actively pick an option (including ‘Not now’ if they didn’t want to contribute anything to the Winter Wallet) before they could move onto the payment page.



Nearly 25,000 Boost Smart PAYG + customers opted in to the Winter Wallet, and they managed to save a whopping 1 million pounds.

7,000 of these customers reached their ambitious targets and received their 5% bonus credit, meaning we credited those customers with a total of around £35,000 towards their energy bills this winter

Remember we’d hypothesised that helping customers save money for the winter using the Winter Wallet, would lead to happy customers who want to stay with us for longer?

To ensure we had the right data to support or reject this hypothesis, we made sure we had a control condition of customers who weren’t exposed to the Winter Wallet. An analysis of the 2 condition shows you’re significantly more likely to stay with us if you were in the Winter Wallet condition.

In addition to improving retention, our customers have been very positive about the Winter Wallet on social media, which should help attract new customers to the brand.

screenshot showing customer feedback from social media




While our Winter Wallet trial had been a success, when we analysed saving behaviours and survey feedback, we saw that 70% of people who joined the scheme didn’t actually meet their savings target, and 30% didn’t save at all.


My analysis of the behaviour and user feedback revealed some key learnings:

1. Not enough time to save

Launching the scheme near the end of summer made it challenging for people to save as much as they wanted in time for winter

2. Customers weren’t motivated enough to keep saving

Our experimental features to encourage people to contribute more money to their Winter Wallet weren’t very effective

3. Our savings incentive didn’t impress

While people valued a way to help them save, our 5% fixed bonus would only earn, for example, £2.50 on a £50 savings target


Our second run of the scheme gave us an opportunity to increase the initiative’s impact. We wanted to help those who struggled the most to save by offering a savings scheme that people can easily stick with — maximising both engagement, and total money saved.

Humans find it difficult to reliably predict their future behaviour; we like to think of ourselves as rational creatures. In reality, we often act in irrational ways. So rather than interview customers to see how we could redesign Winter Wallet to help them save better, I decided to delve deeper into behavioural economics for fresh insights.


In his book, 'Designing for Behaviour Change', Stephen Wendel recommends three strategies for changing behaviours:

Our original solution for the trial was basic. We tried to build a habit of customers saving into their Winter Wallet by prompting them during existing routines, like when they added credit to their balance. But this meant they still had to consciously decide how much (if any) to add to their Winter Wallet.

Saving for the future is hard if you’re financially struggling today. It can be mentally taxing every time you face the decision to put money away to help your ‘future self’ over your immediate needs now.

So I recommended we explore using the 'Cheat' strategy by automating savings: we designed a straightforward set-and-forget mechanism where people could set their savings target and Boost would do the rest. Each day a small amount of credit would automatically transfer from their energy balance to their Winter Wallet to ensure they met their target on time. Customers also needed to be able to handle unpredictable life events so we made it easy for them to lower or pause their contributions.


Now we had an idea to automate savings, I analysed contemporary behaviour change research to draw out insights to guide us further. I discovered that:

  1. Non-savers are 70% more likely to show interest in a prize-linked savings account than savers.
  2. Research shows people are more likely to choose a gamble over a guaranteed fixed reward — suggesting that a ‘chance to win’ mechanic could be a more cost-effective way of encouraging people to save
  3. South Africa’s First National Bank found that a prize-linked savings account was more effective at helping those who are financially struggling than a fixed-interest one
  4. Research has also shown that low-income groups are the most likely to gamble on scratchcards and lotteries

This led me to develop the hypothesis that a prize draw mechanic could better motivate customers to both start, and continue, saving. We could run a monthly prize draw for all savers offering a chance to win various amounts of energy credit, including free energy credit for a year.


As we further developed our new approach to encouraging people to save, I was conscious we had no evidence that these research insights would work in our context.

I recommended that we treat the prize draw as an experiment so we could explore different ways to distribute prizes and see how winning different amounts impacted customer’s likelihood to keep contributing to their Winter Wallet.

It was also critical that I got buy-in from key stakeholders as these ideas were being developed. I collaborated with the PM and commercial team to model scenarios based on the proposed changes. Then we made a compelling case to the MD to get approval for the £100,000 prize fund for the initiative. We then worked with Legal to ensure the prize draw mechanic was compliant. Following legal approval, we briefed Marketing who promoted the proposition to both existing customers as well as using it as a point of difference to drive acquisition. The scheme went live in April 2019.

With the prize draw experiments, I'd made 2 explicit assumptions:

1. Winning any prize will make you more likely to continue saving, compared to winning no prize

2. Winning a low value prize will make you less likely to continue saving, compared to winning a higher value prize.

We tested these assumptions in our first monthly prize draw. The results showed my first assumption was correct — customers who won a prize were more likely to continue saving. Interestingly, my second assumption was wrong — we found that people who won £1 were more likely to continue saving than people who'd won £2.

This led us to try replacing our £2 prizes with 50p ones instead. The results of this experiment showed that people who won 50p were more likely to continue saving than people who won £1. We applied these insights to the remaining monthly prizes draws to help us maximise the number of customers saving.


After optimising Winter Wallet v2, we focused our efforts on promoting it to maximise its adoption. Based on my recommendations, we used the monthly prize draws to drive a sense of urgency to sign up, and we saw engagement peak before each prize draw.

By A/B testing our promotions I worked on at different times in the month, we learnt how to optimise things further; for example, sending an SMS the evening before a prize draw was twice as effective at encouraging sign up compared to those sent on other days.



Did our changes help more people save?

Yes! More than 30% of our customers took part, each saving over £100 on average. Collectively, they saved £4.4 million, quadruple the amount saved in our 2018 trial.

The prize draw mechanic proved an effective means of encouraging saving behaviours from people who find saving challenging. Adoption peaked in the days before a prize draw as customers didn’t want to miss out. And those already saving tended to avoid pausing towards the end of the month when the potential of winning a prize was near.

Customers valued being empowered to save – the Winter Wallet helped Boost double their trustpilot score (from 2 out of 5 to 4 out of 5).

montage of 5 star customer reviews on trustpilot

In addition, Winter Wallet has been recognised at industry awards, winning the 'Enhancing Customer Experience' category at the Marketing Society's Brave Awards and Highly Commended in The Drum Marketing Awards 'Customer Insight' category.