Cold Email Marketing – How to Warm Up A Cold Email Address

Learn about cold email warm ups and why they're essential for your cold email marketing campaigns.

by Asta Geldenhuys

Cold Email Lead Generation | Lead Generation

| 8 min

If you’re planning to launch a cold email marketing campaign using a new email account, you’ll first need to warm up your email address. While this term might sound strange, this process is essential to help build your email’s reputation and boost your delivery rate. Skip this step, and the final destination your emails will reach might well be a spam folder.

Challenges to cold email marketing campaigns

A few hurdles that cold email marketing campaigns have to cross before emails can reach subscribers’ inboxes include email sending limits, spam filtering, and blacklists. Let’s take a quick look at each.

Email sending limits

One way that email servers try to control spam filtering to inboxes is by establishing limits on the number of emails an account can send over a specific time frame. If you exceed this hourly or daily limit, your emails might not get delivered, or, worse, your account could get temporarily banned.

Each email service provider has its own email sending limits. For example, Gmail allows you to send 500 emails per day (though you may not send more than 20 emails per hour). If you use the free Outlook or Zoho plans, this daily limit will be even lower.

Spam filters, traps, and blacklists

After you’ve made sure that you didn’t break these sending limits, you still need to dodge other spam filters. Here, the quality of your contact list and email content and the warmth of your email address will play a role.

How so? If you send cold emails to bad quality email addresses – addresses you haven’t cleaned or verified – you run the risk of getting flagged as a spammer. Once this happens, your cold email marketing campaign is as good as over.

Another risk of sending cold emails to uncleaned and unverified addresses is that some of these addresses might be spam traps. In other words, the goal of these addresses is to find spammers. If your emails are sent to too many spam traps, you could get blacklisted. This will hurt your email deliverability.

While you can use tools to clean and verify your email database (for recommended tools, see our email lead generation guide and our list of recommended data verification tools), you can also mitigate the risks of being blacklisted with a good email warm-up.

What is an email warm-up?

Email warm-ups involve techniques for building your new email account’s reputation and credibility with other email servers. This needs to be done before you run any email campaigns to ensure deliverability. A good way to establish this reputation is by having an active account that sends and receives emails daily.

The challenge with a new email account is that email servers have no way of knowing if the email address is connected to a reputable domain or not, which increases the chances of your emails being blocked, blacklisted, or marked as spam.

If you’re using a new email account to send batches of cold emails simultaneously, this lack of credibility would be an even greater concern, as recipients’ email servers will likely flag your email as potentially harmful and block it from being delivered.

These challenges can be overcome using the following email warm-up techniques.

Email warm-ups: let’s get technical

While warming emails is a pretty straightforward process overall, some of these steps require more technical know-how than others. This includes being able to configure DNS records and knowing best practices for sending cold emails.

Step 1: Set up your email account profile

While tempting, don’t postpone setting up your email account’s profile. Taking the time to fill in all the information requested is an essential step that will help your profile look complete and more credible. So, be sure to add all the required credentials, like your name, surname, avatar, and email signature, to help show email providers that your identity is real.

Step 2: Set up your domain and IP

If your business doesn’t have a domain yet, you’ll need to buy one. A domain (or domain name) is your website’s name –, for example. An IP address is a unique code, or string of numbers, assigned to your domain that helps other servers, local networks, or devices connected to the internet find and identify your website.

Custom email domains linked to your business name (like [email protected]) are better than generic ones for boosting your authenticity. A custom domain adds extra reassurance that emails are being sent from a reliable source.

That said, it’s also critical to warm up your newly registered domain. If your IP address doesn’t have a reputation or hasn’t received a lot of traffic for some time, you will need to warm up your IP address as well. You can do this by setting up your DNS records.

What are DNS records?

Your DNS records refer to your domain name and its corresponding IP address. DNS is short for Domain Name System. Your DNS translates your domain name into your IP address and ensures that other devices, platforms, and tools on the internet can find you. Email servers check incoming emails to confirm they are from an authorized and reputable IP address.

The following are the steps needed to configure your DNS to authenticate your emails.

1. Set up email validation with SPF

SPF is short for Sender Policy Framework. It prevents your email domain from being used to send emails without your knowledge. Hackers often used forged email addresses to send spam and phishing emails from trusted domains. SPF is an email authentication technique that lets receiving mail servers know that an authorized IP address has sent the email.

2. Set up email ownership with DKIM

DKIM records (short for Domain Keys Identified Mail) are digital signatures that you add to your domain server to verify that any emails you send out are not tampered with before reaching a recipient’s server. Authenticating your domain with DKIM records helps prevent email spoofing and increases successful email deliverability.

Step 3: Warm up your email address

To manually warm up an email address instead of relying on a tool to automate the process, you’ll need a database of clean and reputable email addresses (not connected to any cold email marketing campaign). You’ll also need time to send emails to this network, initially one by one (i.e., not in batches) and in increasing numbers, to build your domain authority.

There are recommended formulas for sending schedules that you can use for manually warming up your address. For example, send between 10 to 20 emails a day to your contacts in the first week. After the first week, double the number of emails you sent, and so on.

For this approach to be successful, however, you will also need to ask your email recipient network to look out for and reply to your emails. Ideally, you should receive no less than one reply for every four emails sent (if you are looking to build your domain reputation). Also, be sure that the emails and their replies look authentic, as this will also help build your credibility.

Tools for automating cold email warming

An alternative to the labor-intensive process is to leave this task to tools that can automate your email warm-up for you. These tools help increase your domain reputation by creating positive engagement for your new email account.

How so?

  • They integrate with your email account and send and receive emails on your behalf to increase your email activity.
  • They also automate positive interactions with your email address. Here, your automated emails are sent to their large email databases, where your emails are automatically moved from SPAM into inboxes and marked as important. You’ll also receive replies!

The following are the more popular mail warming tools out there.


Mailwarm boosts your sender reputation by interacting with your emails daily. It automatically sends several emails via your email account to its list of Mailwarm accounts. Plus, it also ensures you receive replies, which positively affects your domain, IP, and email reputations.

Lemwarm by Lemlist

Lemwarm is an email warm-up service that sends emails via your new account to its more than 20,000 strong user base. This means that emails are sent only to real users with email addresses that have been verified. Its service uses an algorithm to create a message and subject line to ensure that the content is unique. Moreover, it will also generate conversations by sending a reply to these unique messages.


Mailgun offers comprehensive email deliverability solutions that will help you to improve delivery rates and protect your sender score. Its features include email authentication to verify your sending domain, IP reputation management, and a managed IP warm-up that fits your specific needs. One of the advantages is that Mailgun will assign a dedicated technical account manager to evaluate your current email strategy. So, you’ll also receive customized advice about how you can improve your cold email marketing strategy.


To improve your email reputation, AutoWarmUp will send automatic emails to the thousands of real users and businesses in its system. Its free service also includes sending automatic replies by mimicking the timing of real human behavior.


Warmbox is used by more than 2,000 businesses, including big brands like Best Buy and Ingram Micro. Warmbox sends emails generated by its artificial intelligence from your inbox to its network of over 10,000 safe, private inboxes. It will then automatically remove the emails from the spam folder, open them, mark them as ‘favorite’ and reply to them. While Warmbox doesn’t offer a free plan, it boasts seamless integration with all email server inboxes.


NeverSpam will automatically send emails to its network of email accounts daily. It will also move these emails from the spam folder to the priority inbox and mark them as important to improve your sender reputation. Lastly, it will also craft and send replies automatically.

Key takeaways on email warming

Most things in life take time. Warming up a new email account or domain is no exception. This process will test your patience and can’t even guarantee 100 percent deliverability. One certain thing is that if you skip this process, your emails will go straight to spam. You might even get blacklisted.

Contact SiteCare for help with your cold email marketing campaigns, or read our cold email marketing benchmarks blog for industry-related, cold email marketing metrics for measuring your own cold email marketing success.

Contact SiteCare

Asta Geldenhuys | Lead Generation Project Manager

Asta is the Lead Generation Project Manager at SiteCare. For three+ years, she has streamlined operations, managed 145 email marketing campaigns, and helped generate 1,400+ leads for global B2B businesses. She has also enjoyed approximately 2,350 cups of coffee while raising three cat kids and documenting life in Cape Town as an amateur photographer.

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