You are currently viewing Why Email Warm-up is Essential for a Cold Email Campaign?

Email warm-up is crucial in a cold email campaign; it is the secret sauce for sustainable email deliverability. Keeping your inbox warm is essential to achieving the highest email deliverability. Email warm-up is an important factor in enhancing email marketing performance.

Many marketers face email deliverability issues due to sending bulk emails, high bounce rates, spam complaint rates, unsubscribe rates, and low engagement rates. Nowadays, email clients have implemented high-standard spam filters that check your email activities and block emails from landing in recipients’ inboxes. To avoid these restrictions, it’s better to implement an email warm-up solution that bypasses spam filters and improves email deliverability.


What is a cold email campaign?

The cold emails campaign is sending emails to non-opt-in contacts. Sending cold emails is not the best practice of email marketing. However, some marketers and sales professionals do that due to high sales pressure and lack of marketing budget.

To get opt-in contacts, you need to spend a lot of money on advertising to get the right people on your list. Many marketers prefer spending less money on advertising due to budget constraints. That’s why they use data mining, data extraction, or third-party email lists to reach the right decision-makers in their niche.

Sending emails to non-opt-in contacts carries the risk of poor email deliverability. If you are extracting contacts from Zoominfo, Uplead, Discovery, Apollo, or Dropcontact, then using email verification tools is necessary to reduce bounce rates. Even if you’re sending emails to your subscriber list, it’s still necessary to verify emails for high email deliverability.


Why do you need to warm-up emails?

If you are sending emails to a cold email list, warming up your inbox is necessary to avoid the spam folder. By conducting an email warm-up, you can deliver your messages to recipients’ inboxes and achieve a better engagement rate for your cold email campaign.

If you notice a sudden drop in email deliverability, the first thing to do is use an email warm-up solution. This boosts your sender reputation and ensures your messages land in customers’ inboxes.

Benefits of warming up emails

  • Ensure your cold email lands in the inbox
  • Increase sender reputation
  • Stop your emails from going to the spam folder
  • Enjoy a higher open rate and engagement rate
  • Help you build trust and reputation with ISPs

Overall, email warm-up is the best way to enhance email deliverability. Read more in our email warm-up guide.


What is the misconception of email warm-up?

Many marketers believe that email warm-up is a one-time activity. They think that once emails are warmed up, they can start sending bulk emails. However, this is a misconception about the email warm-up process. Email warm-up is an ongoing process; even after warming up emails, it’s necessary to gradually increase the volume of emails sent.

Suppose you are sending 500 emails per day; in that case, you should prepare your emails for such a volume through an automated warm-up process. It will take more than 15 days to 1 month to be fully prepared for sending 500 emails. An email warm-up tool builds sender reputation and authentication with an email service provider, which helps increase deliverability.

If you are warmed up email for sending 500 emails but you are sending 1000 emails then after a few days you will see a dip in email deliverability. Therefore, it’s important to maintain consistency and gradually increase the volume. Always keep your email ready based on your requirements and maintain consistency for long-term email deliverability.


Which is the best email warmup tool?

We have analyzed over 10 email warm-up tools, and based on their features, ease of use, automation capabilities, and pricing, we recommend Warmbox. You can find our comprehensive review of Warmbox here.

When you sign up, use the code WELCOME15 to receive a special 15% discount on any plans.


How can you warm-up your inbox with Warmbox?

1. Log in to
2. Choose your email provider (Gmail, Outlook, Yahoo!, Sendgrid, Sendinblue, etc.) and link your inbox.
3. Set up your warm-up campaign parameters (like the warm-up recipe, sending volume, reply rate, etc.).
4. Wait a few weeks for the warm-up process to take effect.
5. Relax and enjoy the boost in deliverability.
6. Keep calm! Warmbox will automatically maintain your inbox warmth as long as your campaign is active.

Make the most of your cold emailing campaigns with Warmbox!



Warming up your inbox for cold email campaigns is a crucial step in ensuring the success and effectiveness of your email marketing efforts. By gradually increasing your email sending volume, establishing sender reputation, and bypassing spam filters, you can significantly improve your email deliverability rates.

Warming up your inbox not only enhances the chances of your emails reaching recipients’ inboxes but also helps to build trust and credibility with Internet Service Providers (ISPs). Ultimately, investing the time and effort into warming up your inbox can lead to higher open rates, engagement rates, and overall success in your cold email campaigns.