Warming up your IP allows you to gradually send more emails over your new IP to establish a good sender reputation. All IP’s have at one point started as cold IP’s (no reputation) and need work to build sending reputation up. pre-warmed IP’s have already completed the warming stage and are ready right of way after purchase.
IP warming is the practice of gradually increasing the volume of mail sent with a dedicated IP address according to a predetermined schedule. This gradual process helps to establish a reputation with ISPs (Internet Service Providers) as a legitimate email sender with a pre-warmed IP, you can start sending high volume right away.
When an ISP observes email suddenly coming from a new or “cold” IP address, they will take notice and immediately begin evaluating the traffic coming from that IP. Since ISPs treat email volume as a key determining factor when detecting spam, it is best to begin sending a low to moderate volume, eventually working your way up to larger volumes when using new dedicated IP’s. This gives the receiving email providers a chance to closely observe your sending habits and record how your recipients engage with your email.
Pre-warmed IP’s are $24.99 per month and New Dedicated (COLD) IP’s are $7.95 per month (require warming before high volume sending).
Check out this awesome article “How to warm your dedicated IP“.