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Bio-Gard increased product orders with Doordrop Media and Partially Addressed Mail

April 2021

Bio-Gard increased product orders with a tactical approach to door drop media and partially addressed mail

Biogard creative

Campaign Objective

  • Bio-Gard wanted to raise awareness and continue recruiting customers for Muck Munchers Biological Septic Tank Treatments during the Covid-19 lockdown in 2020
  • Bio-Gard were keen to select channels that could reach target homes, whilst remaining GDPR compliant
  • Bio-Gard appointed Whistl to plan both the door drop media and partially addressed mail (PAM) campaigns, targeting prospect rich postcodes and postcode sectors across the UK.
  • The strategy was to deliver tangible communications, engage with homes owning a septic tank and convert them to buy Muck Munchers.


  • The strategy used two forms of advertising mail, delivered directly to targeted homes. The reach of the two methods could then be compared for engagement and performance:
  • Door drop at the postcode sector level
  • PAM to individual postcode prospects.
  • Whistl created profiles and predictive models to identify the key individual postcodes and postcode sectors with high penetrations of septic tanks, to maximise response using:
    • Anonymised historic customer sales data
    • Bio-Gard’s extensive UK prospect database
    • Mosaic demographic modelling
  • Creatively a 4-page leaflet was created for the door drop schedule, while PAM used a more traditional direct mail envelope format with 'Dear Septic Tank Owner' vs. 'Dear Homeowner' salutations tested.
  • Each creative explained how Muck Munchers work and 50% of households also received a £1 NHS charity donation promotional message to understand impacts on response rates.

Campaign Results

  • The campaign reached 610,000 households, generating 2,866 orders, confirming that targeting was attracting an audience who owned a septic tank.
  • 0.47% response rate produced a 5-month 48% return on investment.
  • Year-on-Year response levels increased 31% and ROI by more than double.
  • Doordrop provided greater reach, with 88% of orders from new customers, boosted by existing customers receipt for re-order of products.
  • Partially Addressed Mail generated near 100% new customers and over 50% ROI.

Bio-Gard Case Study


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