Summary
For optimal email deliverability and sender reputation, unengaged email subscribers should almost universally be segmented and sent separate, targeted re-engagement campaigns, rather than being mixed with active recipients in regular broadcasts. Sending to inactive users significantly harms key metrics, including open rates and click-through rates, and leads to increased spam complaints, ultimately degrading sender reputation and overall deliverability. By isolating unengaged segments, marketers can protect the performance of their campaigns to active subscribers, while dedicating specific efforts to either reactivate or safely remove inactive contacts, thereby maintaining a healthy and high-performing email list. While some tactical exceptions exist for minimal inclusion, the overwhelming consensus from email marketing experts and major email service providers is a strong recommendation for distinct re-engagement strategies for unengaged subscribers.
Key findings
- Improved Engaged Campaign Performance: Separating unengaged subscribers from regular sends demonstrably leads to significant improvements in open rates and overall deliverability for campaigns sent to active, engaged recipients. One marketer reported open rates rising from 6% to 15% and overall deliverability from 98% to 99.9% after making this change.
- Damage from Mixed Sends: Consistently including unengaged recipients in regular email campaigns severely harms sender reputation, lowers overall open and click-through rates, increases spam complaints, and negatively impacts deliverability metrics across the board.
- Holistic Assessment by Mailbox Providers: Most mailbox providers assess sender performance holistically. Low engagement from a segment of unengaged recipients, even if part of a larger send, can drag down the performance of the entire campaign and signal a lack of interest to ISPs.
- Low Engagement in Re-engagement Campaigns: Re-engagement campaigns, by their nature, typically have very low open rates (e.g., 0.2%). This low performance, when isolated, prevents it from negatively influencing the metrics of campaigns sent to active subscribers.
- ISP Engagement Tracking: ISPs closely track subscriber engagement. A consistent pattern of emailing non-openers indicates that emails are not desired, which can lead to increased filtering or blocking, even for messages to active users.
Key considerations
- Strategic Segmentation: Always segment unengaged subscribers into a distinct group, separate from your active recipients, to maintain a healthy email list and protect your sender reputation. This is a foundational step for any effective deliverability strategy.
- Dedicated Re-engagement: Develop and execute a specific re-engagement campaign series for inactive subscribers, typically consisting of 3-5 emails. This targeted approach aims to either reactivate them or identify them for removal, ensuring your main campaigns are not negatively impacted.
- Protecting Reputation: The primary driver for separating these audiences is to safeguard your sender reputation. Sending regular campaigns to uninterested users signals to mailbox providers that your content is irrelevant, leading to lower deliverability for all your emails.
- List Hygiene: View re-engagement campaigns as a crucial component of ongoing list cleaning. The ultimate outcome for unengaged subscribers is either successful reactivation or their safe removal, both of which contribute to improved deliverability and return on investment.
- Volume Control for Mixed Sends: If, in rare cases, a small portion of unengaged users is included in a regular send, their volume should be strictly controlled, ideally no more than 20% of your engaged audience, and the campaign should be sent to the engaged segment first.
- Gradual Re-engagement for Large Lists: For very large lists of inactive subscribers, consider re-engaging them by including a small, rotating segment (e.g., 5,000 names) in daily broadcasts rather than attempting a single, large send to everyone at once.
- Dedicated 'Time Out' IP: For large-scale re-engagement efforts, consider using a separate, dedicated 'time out' IP address to isolate any potential negative deliverability impact from these lower-performing sends.
What email marketers say
14 marketer opinions
The overwhelming expert consensus advises against mixing unengaged email subscribers with active recipients. Instead, marketers should segment these inactive contacts and send them separate, dedicated re-engagement campaigns. This approach is crucial for preserving sender reputation, maintaining high deliverability rates for engaged audiences, and ensuring the overall health of the email list. Sending regular campaigns to uninterested subscribers negatively impacts key performance indicators like open rates and click-through rates, increases spam complaints, and signals to mailbox providers that the content is irrelevant, which can harm deliverability for all sends. While limited, strategic inclusion might be considered in very specific, controlled scenarios, the core strategy should always prioritize isolation and targeted re-engagement or eventual removal of inactive contacts.
Key opinions
- Improved Engaged Campaign Performance: Separating unengaged subscribers leads to significantly higher open rates and improved deliverability for campaigns targeting active subscribers.
- Negative Impact of Mixed Sends: Including unengaged recipients in regular campaigns demonstrably lowers overall engagement metrics, increases spam complaints, and degrades sender reputation and deliverability.
- Holistic Provider Assessment: Mailbox providers generally assess sender performance holistically; separating audiences helps to isolate the negative metrics from unengaged segments, preventing them from dragging down the performance of engaged sends.
- Low Engagement in Re-engagement: Dedicated re-engagement campaigns, while essential, typically have very low open rates, further justifying their separation from high-performing active campaigns.
- Primary Cause of Deliverability Issues: Sending emails to consistently unengaged subscribers is a leading cause of deliverability problems, as it signals a lack of interest to ISPs.
Key considerations
- Mandatory Segmentation: Always segment unengaged subscribers into a distinct group for targeted re-engagement or removal, safeguarding your sender reputation and list health.
- Dedicated Re-engagement Campaigns: Implement a structured re-engagement series, often 3-5 emails, specifically designed to reactivate inactive subscribers.
- List Hygiene for Deliverability: Re-engagement efforts are a critical part of ongoing list cleaning, aiming to either re-activate subscribers or identify them for removal to maintain optimal deliverability and ROI.
- Limited Inclusion Strategy: If, exceptionally, unengaged users are included in a regular send, their volume should be strictly limited, for example, a maximum of 20% of the engaged audience, and the send should prioritize the engaged segment first.
- Gradual Re-engagement for Large Lists: For extensive lists of inactive subscribers, consider a gradual approach by incorporating small, rotating segments, such as 5,000 names, into daily broadcasts rather than large, one-off sends.
- Consider a Dedicated 'Time Out' IP: For large-scale or risky re-engagement efforts, using a separate, 'time out' IP can help mitigate any potential negative impact on the primary sending reputation.
Marketer view
Marketer from Email Geeks responds that sending a special message to inactives might make more sense than mixing them with standard messages, noting that sender reputation can still be leveraged if the volume and context are reasonable.
4 May 2024 - Email Geeks
Marketer view
Marketer from Email Geeks explains that while some filter providers fingerprint messages, most mailbox providers look at things holistically. They add that if fingerprinting does occur, metrics from less engaged streams won't hurt more engaged messages as much, suggesting that separating might lead to a win either way.
24 Jun 2023 - Email Geeks
What the experts say
2 expert opinions
To safeguard email deliverability and sender reputation, it is crucial to avoid including unengaged subscribers in regular campaigns intended for active recipients. Email marketing experts strongly advise segmenting inactive users and deploying separate, specialized re-engagement campaigns for them. Consistently sending emails to those who do not engage signals a lack of interest to Internet Service Providers, which can severely damage sender reputation, lead to emails being filtered or blocked, and ultimately hurt the deliverability of all your messages. Focusing primary campaigns on engaged audiences while using targeted strategies for re-engagement helps maintain a healthy sending environment and improves overall email performance.
Key opinions
- Sender Reputation Impact: Sending to a full list with many unengaged users significantly harms sender reputation.
- Deliverability Risk: Mixing unengaged subscribers with active ones in regular campaigns can negatively impact overall deliverability.
- ISP Engagement Monitoring: ISPs track recipient engagement; consistent emailing of non-openers indicates low interest and can lead to filtering or blocking.
- Segmentation for Health: Segmenting unengaged subscribers and using specific re-engagement tactics is vital for protecting sender reputation and maintaining email list health.
- Tailored Re-engagement: Separate, tailored re-engagement campaigns are recommended for inactive subscribers rather than including them in main broadcasts.
Key considerations
- Prioritize Engaged Audiences: Focus your main email campaigns primarily on your active and engaged subscriber base to protect deliverability metrics.
- Implement Separate Campaigns: Create and execute distinct re-engagement campaigns specifically designed for unengaged subscribers.
- Monitor Engagement Signals: Be aware that ISPs use engagement metrics to determine sender trustworthiness, making it critical to manage your unengaged segments.
- Proactive Segmentation: Regularly segment your list to identify and isolate inactive subscribers, preventing them from negatively impacting your overall sending reputation.
Expert view
Expert from Spam Resource explains that sending to a full list, including many unengaged users, can negatively impact sender reputation. He advises focusing main campaigns on engaged users and running separate, tailored re-engagement campaigns for inactive subscribers, as mixing them can hurt deliverability.
9 Feb 2024 - Spam Resource
Expert view
Expert from Word to the Wise shares that consistently emailing non-openers can damage sender reputation because ISPs track engagement. Low engagement from a large segment of recipients indicates a lack of interest, which can lead to emails being filtered or blocked. Therefore, it's better to segment unengaged subscribers and use specific re-engagement tactics rather than including them in regular campaigns.
9 May 2024 - Word to the Wise
What the documentation says
6 technical articles
Email marketing platforms and experts consistently advise against including unengaged subscribers in regular campaigns for active recipients. Instead, it is crucial to segment inactive contacts and deploy separate, targeted re-engagement efforts. This strategy is essential for protecting sender reputation and maximizing overall email deliverability. Mixing unengaged users with active ones can severely dilute engagement metrics, increase spam complaints, and signal to Internet Service Providers that your content is irrelevant, ultimately leading to messages being filtered or blocked. By maintaining distinct campaigns for re-engagement or eventual removal, businesses can ensure their primary communications reach a responsive audience and preserve the health of their email list.
Key findings
- Mandatory Segmentation: Leading email service providers like Mailchimp, Constant Contact, and Aweber explicitly recommend segmenting unengaged subscribers for separate treatment, rather than mixing them with active recipients.
- Reputation Harm from Mixing: Consistently sending emails to unengaged subscribers in regular campaigns significantly harms sender reputation and can lead to increased spam complaints and lower overall deliverability, as noted by SendGrid and Validity.
- Impact on Engagement Metrics: Inactive subscribers negatively impact key engagement metrics, such as open rates and click-through rates, which can drag down the performance perception of your entire mailing list.
- ISP Perception of Irrelevance: Internet Service Providers closely monitor subscriber engagement. Sending to non-responders signals a lack of interest, potentially leading to increased filtering or blocking of all your emails, even those sent to active users.
- Goal of Re-engagement Campaigns: Dedicated re-engagement or 'win-back' campaigns serve a dual purpose: to prompt inactive subscribers to re-engage or to facilitate their safe removal, thereby improving list health and deliverability.
Key considerations
- Prioritize Segmentation: Always segment your email list to identify and isolate unengaged subscribers, as this is fundamental for maintaining a healthy sending reputation and high deliverability.
- Utilize Targeted Campaigns: Develop and implement specific re-engagement campaigns designed to encourage interaction from inactive contacts, keeping them separate from your main marketing efforts.
- Focus on List Health: Regularly assess and clean your email list by either re-engaging or removing unengaged subscribers, ensuring your primary sends reach the most responsive audience.
- Monitor Deliverability Signals: Be aware that including unengaged recipients in your regular sends sends negative signals to ISPs, which can lead to poorer inbox placement across the board.
Technical article
Documentation from Mailchimp Knowledge Base explains that re-engagement campaigns are specifically designed for unengaged subscribers, strongly implying they should be separate from regular campaigns. The goal is to either prompt these subscribers to re-engage or to safely remove them from the list, thereby maintaining a healthy audience and good sender reputation for improved deliverability.
7 May 2025 - Mailchimp Knowledge Base
Technical article
Documentation from SendGrid Blog explains that sending emails to unengaged subscribers can significantly harm sender reputation. While not explicitly stating 'separate campaigns,' their emphasis on 'list cleaning' and 'removing inactive users' strongly implies that these subscribers should not be mixed with active recipients for regular campaigns, highlighting the negative impact on overall deliverability if they are.
31 May 2025 - SendGrid Blog
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