Warmup

Pre warmed inboxes vs warming them yourself. I tested both and the numbers are clear

warmup_data · 2026-03-12T00:00:00Z

Bought 20 standard inboxes and warmed with Instantly for 21 days. Bought 20 pre-warmed from PuzzleInbox that were ready day 1. Compared inbox placement at

warmup_data · 2026-03-12 · 2,190 views

I wanted real data on whether pre-warmed inboxes are actually worth the premium over warming them yourself. So I ran a controlled test.

Group A: 20 standard Google Workspace inboxes purchased from a generic provider. Connected to Instantly warmup on day 1. Warmed for 21 days before sending any cold emails. Cost: $2.50 per inbox = $50 total. Plus Instantly warmup (included with my plan).

Group B: 20 pre-warmed Google Workspace inboxes from PuzzleInbox. Ready to send on delivery. Cost: $4 per inbox = $80 total.

Inbox placement measured via GlockApps at each checkpoint:

Day 1: Group A: 31% inbox placement. Group B: 85% inbox placement.
Day 7: Group A: 52% inbox placement. Group B: 87% inbox placement.
Day 14: Group A: 71% inbox placement. Group B: 88% inbox placement.
Day 21: Group A: 79% inbox placement. Group B: 89% inbox placement.

Group A did not hit 80% inbox placement until day 18. Group B started at 85% on day 1 and climbed from there.

What this means in real numbers: Group B was sending cold emails and booking meetings from day 1. Group A sat idle for 18-21 days. Over those 3 weeks, Group B's 20 inboxes at 15 emails/day sent 6,300 cold emails. At a 3.5% reply rate, that is 220 replies. At 50% meeting conversion from positive replies, that is roughly 55 meetings that Group A completely missed.

The cost difference: $30 more for pre-warmed inboxes ($80 vs $50). The value of 55 meetings at even $100 per meeting in expected revenue: $5,500. The ROI on that $30 premium is absurd.

There is also a risk factor. 3 of my 20 self-warmed inboxes (Group A) never reached 80% placement even after 21 days. Something in the warmup did not work properly, maybe bad luck with the warmup network, maybe those specific accounts got off to a rough start. I had to replace them. That is a 15% failure rate on self-warmed inboxes. All 20 PuzzleInbox inboxes performed consistently.

The data settled this question for me. I only buy pre-warmed now. The 3 weeks of lost sending time plus the risk of warmup failure makes self-warming a bad deal even though the per-inbox cost is lower. You pay more per inbox but you make far more per inbox.