Filter Buy sells replacement air filters for homes and businesses across the continental US — hundreds of sizes and major brands — with messaging built around seasonal reminders, allergies, and simple replenishment.
Their email program leaned on timely campaigns: daylight savings as a nudge to swap filters, spring allergy angles paired with product picks, and bright mobile layouts with free-shipping banners and clear green CTAs. That creative consistency mattered once we could scale volume to engaged segments without tanking deliverability.
Campaign creative
Seasonal sends and replenishment messaging — mobile-first layouts with clear offers and branded green CTAs.
The challenge
After two years on SendGrid, FilterBuy moved to Klaviyo with almost no engagement data, only a few automations, and no regular campaigns. They needed migration support, list warm-up, and a plan to grow email revenue safely.
The solution
Post-migration, we built a tailored content and sending strategy: segment by recency, prioritize high-engagement flows first, and expand automations so behavior could inform campaigns.
The idea behind this was to ensure great engagement numbers, good warm-up of the list, and to provide the needed engagement numbers as a base for developing a target audience for the first campaigns.
— Dejan Georgiev, Senior Account Manager, Essence of Email
The results
By April 2019, email revenue reached 138× the December 2018 baseline — driven by disciplined segmentation and scaling volume only where engagement supported it.
Email revenue growth
Indexed to December 2018 — the program reached 138× that baseline by April 2019 with segmentation-first sending.
Spam complaints were initially above a healthy threshold. Klaviyo’s guidance is clear: mailing unengaged subscribers trains mailbox providers to treat you as a bulk sender. We built engaged segments so mail went to people who wanted it.
Spam complaint rate
Engaged segments and disciplined cadence brought complaints down from 0.24% to 0.06% while volume scaled.
In the first four months, spam rate fell from 0.24% (December 2018) to 0.06% (April 2019) while send volume increased dramatically — proving that engagement-first sending scales better than list-wide blasts.
Total email sent
Volume ramped as engagement segments proved out — April reached roughly 640K sends in this window.
Book a strategy call to explore what a similar program could look like for your brand.