The Sunset Flow: How to Clean Your Email List Without Losing Subscribers

Here’s a truth most e-commerce brands don’t want to hear: 30-50% of your email list is dead weight. These are subscribers who haven’t opened, clicked, or purchased in months. They’re dragging down your open rates, tanking your sender reputation, and silently destroying your deliverability.

The instinct is to keep them. “But they opted in! What if they buy someday?” Here’s the reality: a subscriber who hasn’t engaged in 180+ days has a less than 2% chance of ever purchasing. Meanwhile, keeping them on your list is actively hurting the 50-70% of subscribers who do want to hear from you — because poor engagement metrics cause mailbox providers to filter more of your emails to spam.

A sunset flow solves this. It’s a last-chance re-engagement sequence that gives unengaged subscribers a reason to come back — and gracefully removes the ones who don’t. Done right, it recovers 3-8% of unengaged subscribers while improving deliverability for everyone else.

Key Takeaways

• Unengaged subscribers cost you money through reduced deliverability — they’re not “free to keep”
• A sunset flow recovers 3-8% of unengaged subscribers and removes the rest cleanly
• The ideal sunset flow has 3-4 emails over 14-21 days
• Always suppress (don’t delete) unengaged contacts — you may need them for advertising audiences
• Klaviyo’s engagement metrics and segment conditions make sunset flows straightforward to implement
• Running a sunset flow quarterly maintains list health and protects sender reputation year-round

Why You Need a Sunset Flow

The Cost of Unengaged Subscribers

Let’s run the numbers on a 100,000-subscriber list where 35% (35,000 people) are unengaged:

Direct cost:

• Klaviyo pricing is based on active profiles. At 100,000 profiles, you’re paying approximately $1,380/month. Remove 35,000 unengaged profiles and your bill drops to around $720/month. That’s $7,920 saved per year.

Indirect cost (deliverability damage):

• Gmail, Yahoo, and Outlook track how many of your emails are opened, clicked, and ignored
• When 35% of your recipients never engage, mailbox providers interpret this as “this sender’s emails aren’t wanted”
• Result: more emails going to spam or Promotions tab for everyone, including your engaged subscribers
• Conservative estimate: 10-20% of engaged subscribers’ emails are being filtered due to poor list-level engagement
• On 65,000 engaged subscribers, that’s 6,500-13,000 people missing your emails
• At $0.08 RPR, that’s $520-$1,040 lost per campaign, or $27,000-$54,000 per year if you send weekly

Total annual cost of not running a sunset flow: $35,000-$62,000 for a 100K list. The numbers are proportionally similar for smaller lists.

What Happens After a Sunset Flow

Brands that run their first sunset flow typically see these changes within 30 days:

• Open rates increase 25-45% (because the denominator is now engaged subscribers)
• Click rates increase 15-30%
• Deliverability improves — more emails reaching Primary inbox instead of Promotions/Spam
• Revenue per recipient increases 20-40% (the metric that matters for ROI)
• Spam complaint rate drops 30-50% (unengaged recipients are more likely to mark as spam than unsubscribe)

Yes, your total list size shrinks. But every metric that matters for revenue improves.

Who to Include in the Sunset Flow

Defining “Unengaged”

The definition of unengaged varies by brand, but here’s the framework we use:

Primary criteria (must meet all):

• Has not opened any email in the last 120-180 days
• Has not clicked any email in the last 120-180 days
• Has not placed an order in the last 180 days
• Has not visited your website in the last 90 days

Secondary criteria (additional signals):

• Has received at least 15 emails (they’ve had ample opportunity to engage)
• Has been on the list for at least 120 days
• Is not a recent subscriber who just hasn’t had time to engage

Building the Segment in Klaviyo

Go to Lists & Segments > Create Segment and set these conditions:

Definition: Sunset Candidates

• “What someone has done > Received Email > at least 15 times > over all time”
• AND “What someone has done > Opened Email > zero times > in the last 150 days”
• AND “What someone has done > Clicked Email > zero times > in the last 150 days”
• AND “What someone has done > Placed Order > zero times > in the last 180 days”
• AND “What someone has done > Active on Site > zero times > in the last 90 days”
• AND “Person > Date Added > is before 120 days ago”

This segment updates dynamically. As people disengage, they’ll enter the segment. As they re-engage (open an email, visit your site), they’ll automatically exit.

Important: Who to Exclude

Don’t sunset these groups:

• Recent subscribers (< 120 days): They haven’t had enough time or emails to establish a pattern
• Customers with high lifetime value: A customer who spent $2,000+ might be worth keeping even if they’ve been quiet. Create a separate, gentler re-engagement flow for high-CLV unengaged contacts
• Subscribers who recently visited your site: If Klaviyo’s on-site tracking shows recent activity, they’re engaged — just not with email. They may prefer browsing to clicking email links

The Sunset Flow: Step by Step

Flow Architecture

Trigger: Customer enters the “Sunset Candidates” segment

Time delays and emails:

• Email 1: Immediate
• Email 2: 5 days after Email 1
• Email 3: 5 days after Email 2
• Email 4: 5 days after Email 3
• Suppression: 3 days after Email 4

Total duration: 18 days from entry to suppression

Email 1: The Re-Engagement Hook

Goal: Get their attention and give them a reason to stay.

Subject line options:

• “We haven’t heard from you in a while”
• “Is this goodbye? (We hope not)”
• “Your inbox, your rules — but we’d love you to stay”

Content framework:

• Acknowledge the gap: “We noticed you haven’t opened our emails recently”
• Remind them of value: What they’re missing (new products, content, exclusive offers)
• Give a compelling reason to re-engage: Exclusive discount, early access, or a curated selection based on their past purchases
• Clear CTA: “I’m still interested” button that clicks through to your site (any click counts as engagement)
• Subtle stakes: “If we don’t hear from you, we’ll stop sending emails to keep your inbox clean”

Design:

• Text-heavy (images can be blocked by email clients, and unengaged subscribers often have images off by default)
• Single, prominent CTA button
• Short — 150-200 words max

Email 2: The Value Proposition

Goal: Show them what they’re missing with specific, tangible value.

Subject line options:

• “Here’s what you’ve missed (it’s good)”
• “3 things that happened since we last connected”
• “Before we part ways — one more thing”

Content framework:

• Lead with your best recent content: New bestsellers, popular blog posts, customer stories
• Include a compelling offer (if you didn’t in Email 1): 15-20% off their next order
• Social proof: “Join 50,000+ subscribers who look forward to our emails”
• Stronger urgency: “We’ll remove you from our list soon if we don’t hear back”
• Same clear CTA button

Email 3: The Final Offer

Goal: Maximum incentive for subscribers who need a strong push to re-engage.

Subject line options:

• “Last chance: 20% off before we say goodbye”
• “We’re about to remove you — but first, a gift”
• “Final email: Here’s 20% off to stay”

Content framework:

• Direct: “This is one of the last emails you’ll receive from us”
• Best offer: Your strongest incentive (highest discount, free shipping + discount, free gift)
• Make it easy: One-click to stay, one-click to shop with the discount applied
• Reinforce what they’ll miss: “No more early access, exclusive offers, or first looks at new products”

Email 4: The Goodbye

Goal: Final notice before suppression. Also serves as a win-back trigger for the most loss-averse subscribers.

Subject line options:

• “Goodbye (for now)”
• “We’re removing you from our list tomorrow”
• “This is our last email to you”

Content framework:

• Brief and respectful: “We’re removing you from our email list to keep your inbox clean”
• One last CTA: “Wait, I want to stay” button
• No discount — this email is about the relationship, not the transaction
• Include a note that they can always resubscribe later
• Thank them for being part of your community

Post-Flow: Suppression

3 days after Email 4, for anyone who didn’t open, click, or purchase during the flow:

Add them to a Suppression List in Klaviyo. Do NOT delete them.

Why suppress instead of delete:

• Suppressed profiles don’t count toward your Klaviyo billing
• You retain their data for analysis and custom audiences (Facebook, Google)
• If they re-engage in the future (visit your site, make a purchase), you can un-suppress them
• Deleting is permanent — you lose all historical data

Setting Up Suppression in Klaviyo

1. Create a list called “Sunset Suppressed”
2. At the end of your sunset flow (after the final time delay), add a Profile Property Update action that adds the person to this list
3. In all your campaign sends and flow triggers, exclude the “Sunset Suppressed” list
4. Alternatively, use Klaviyo’s built-in suppression feature: add a Suppress Profile action at the end of the flow

Optimizing Your Sunset Flow

A/B Tests Worth Running

Subject lines: The sunset flow is where unusual, pattern-breaking subject lines work best. Test:

• Direct (“We’re removing you from our list”) vs. Curiosity (“Is this the end?”)
• Question (“Still want to hear from us?”) vs. Statement (“We miss you”)
• With emoji vs. without (emojis can cut through a cluttered inbox)

Offer strength: Test no offer vs. moderate discount vs. aggressive discount in Email 1. Sometimes a simple “click here to stay” with no offer outperforms a discount — the commitment is the incentive.

Flow length: Test 3 emails vs. 4 emails. Some audiences re-engage faster; others need more time.

Timing between emails: Test 3-day gaps vs. 5-day gaps vs. 7-day gaps. Shorter gaps create more urgency but also more pressure.

Benchmarks for Sunset Flow Performance

Metric	Below Average	Average	Above Average
Re-engagement rate (any open/click)	< 3%	5-8%	10%+
Conversion rate (purchase during flow)	< 0.5%	1-2%	3%+
Unsubscribe rate from flow	2-4%	5-8%	8-12%*

*A high unsubscribe rate in a sunset flow is actually positive — it means people are self-selecting out, which saves you the suppression step and is a cleaner exit.

What to Do With Recovered Subscribers

Subscribers who re-engage during the sunset flow should be treated carefully:

1. Move them to a “re-engaged” segment for 60 days
2. Send them your best content during this window to rebuild the habit
3. Monitor their engagement closely — if they go quiet again within 60 days, suppress without running the full sunset flow again
4. Don’t immediately blast them with high frequency — ease them back in with 1-2 emails per week

Running Sunset Flows on an Ongoing Basis

A sunset flow isn’t a one-time event. It should run continuously.

The Ongoing Setup

Because your sunset segment is dynamic (people enter as they become unengaged), the flow triggers automatically whenever someone meets the criteria. You don’t need to manually initiate it.

But you should audit it quarterly:

• Is the segment criteria still appropriate? (Adjust the 150-day window based on your data)
• Are the emails still performing? Check open/click rates and re-engagement rates
• Is the offer still competitive? Update discounts and value propositions
• How large is the “Sunset Suppressed” list? Track growth rate — if it’s growing faster than your list, you have an acquisition or content problem

Preventing the Need for Sunset

The best sunset flow is one that doesn’t need to exist. Reduce the flow into your sunset segment by:

• Setting engagement expectations at signup: Tell subscribers what they’ll receive and how often
• Sending relevant content: Segmentation and personalization keep subscribers engaged
• Respecting frequency preferences: Give subscribers control over how often they hear from you
• Maintaining deliverability: Emails that land in spam create unengaged subscribers
• Monitoring early warning signs: Create a “cooling off” segment (90-120 days no engagement) and adjust content/frequency before they hit the 150-day mark

The Preference Center Alternative

Before suppressing someone, give them one more option: a preference center.

In Email 3 or Email 4 of your sunset flow, include a link to a preference center where subscribers can:

• Reduce email frequency (weekly instead of daily)
• Select content topics they’re interested in
• Switch to SMS-only or a monthly digest
• Confirm unsubscribe

This captures subscribers who still want a relationship with your brand but were overwhelmed by frequency or irrelevant content. We typically see 5-10% of sunset flow recipients update their preferences instead of fully disengaging — and those adjusted preferences lead to significantly better long-term engagement.

The Bottom Line

A sunset flow is not about giving up on subscribers. It’s about respecting their inbox, protecting your deliverability, and focusing your resources on the subscribers who actually want to hear from you.

Every unengaged subscriber you keep on your list is making your emails less effective for everyone. The math is clear: a smaller, engaged list outperforms a larger, disengaged list on every metric that matters for revenue.

Run the sunset flow. Trust the data. Your deliverability (and your revenue) will thank you.

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