A/B Split Testing - BAXI Heating

A/B split testing is a method whereby you test different emails in a campaign to see which one performs better. Then the remainder of the audience is sent the best performing email. This allows you to understand what your audience wants, and it can improve opens, clicks and click-through rates. By regularly conducting split tests, you can keep your emails engaging for your audience as possible. There are many areas to test, from subject lines to personalisation and creation.

In this split test, we tested the length of the email and differences in Call To Actions (CTAs).


We conducted a split test on two emails, one with more content but the opportunity to book onto events and one with less content to see which one performed better. Regular split tests are important as your audience requirements may change, and to know what the audience wants, you need to test different ideas. Even if your audience requirements are the same changing the design or CTA type may mix it up enough to gain more engagement instead of hitting a plateau. 

See further details of the split test below.

Design A

Design A outperformed with the most clicks and was used in this particular campaign. This email was shorter and included a ‘reprise section’ (after the dotted line). The reprise section incorporated 3 call to action’s in the form of blue text hyperlinks.

Email A

DIstinct Emails Opened


Distinct Clicks (People)


Unique Links Clicked


Baxi test email screenshot A inside iPhone

Design B

In comparison to design A, design B was longer and the ‘reprise section’ (after the dotted line) included 9 call to action’s in the form of blue text hyperlinks with two grey boxes. This design split the dates up nicely and enabled the user to book onto a training event.

Email B

DIstinct Emails Opened


Distinct Clicks (People)


Unique Links Clicked


Baxi test email screenshot B inside iPhone


In Adroit’s experience, emails perform better if the email is concise with a clear Call To Action. It is also important to note that although your brand may have a lot of important content that needs to be shared, that too many call to actions could overwhelm the user and negatively impact the number of clicks.