HubSpot Email vs. Furnace
Why the infrastructure matters more than the message
Most teams treat email as a single category. Send a message, hit a list, hope for replies. But the infrastructure behind your sending determines whether your message lands in the inbox or quietly disappears into spam. Traditional CRM platforms like HubSpot Email are built for something very different than cold outreach, and the differences matter.
HubSpot Email
CRM email campaigns and sequences
Cold Email Best Practices
Furnace infrastructure
Sends from shared IP pools with "noisy neighbor" effects
Sends from 20+ inboxes on private, dedicated infrastructure
Uses your main domain, risking reputation; violates Acceptable Use Policy for cold outreach
Uses dedicated sending domains to protect the brand
Sends thousands at once (bulk blast); no send randomization
Sends 20-30 emails/inbox/day with natural sending patterns
Uses HTML templates that look like marketing
Uses plain-text messages that feel 1:1 and personal
Prohibits cold outreach; no domain warm-up, send randomization, or pre-send risk analysis
Built for cold outreach with domain warm-up, natural patterns, and full risk management
CRMs are fantastic for nurturing relationships.
Furnace is engineered to start them safely, predictably, and at scale.
When "good enough" infrastructure kills your deliverability
We've seen this happen, and chances are you know a couple companies that have made the same mistake. Here's a hypothetical scenario that illustrates what can go wrong:
Imagine a fictional B2B SaaS company called "AcmeWorkflow" (completely made up). Their sales director decides to use HubSpot Sequences for cold outreach because the team already uses HubSpot for marketing emails and CRM. Seems logical, right?
They upload 5,000 cold prospects and hit send. The first week looks promising — emails are going out, a few replies trickle in. They think they've cracked the code.
But by week three, deliverability starts dropping. Emails that used to land in inboxes are now going straight to spam. Their reply rate, which started at 2%, plummets to 0.3%. Then they get a warning from HubSpot about their Acceptable Use Policy. They don't know why.
What went wrong (in this hypothetical scenario):
- •They sent from their main domain — acmeworkflow.com — the same domain used for customer support, marketing newsletters, and internal communications.
- •HubSpot Email uses shared IP pools, exposing them to "noisy neighbor" effects where other senders' poor practices can impact their deliverability.
- •HubSpot explicitly prohibits cold email outreach in their Acceptable Use Policy — they risk account suspension or termination.
- •HubSpot Email lacks essential cold email features like domain warm-up, send randomization, and pre-send risk analysis.
- •Their legitimate marketing emails started landing in spam too, damaging relationships with existing customers.
In this fictional scenario, AcmeWorkflow would face account warnings or suspension from HubSpot, have to rebuild their entire email infrastructure from scratch, lose months of outreach momentum, damage their brand reputation, and spend thousands on domain remediation. All because they used the wrong tool for the job.
The infrastructure you use for cold outreach doesn't just affect deliverability — it can permanently damage your domain reputation, get your account suspended, and hurt your entire email program.
Ready to build the right infrastructure?
Schedule a quick call — we'll show you how Furnace systems turn cold outreach into predictable opportunity flow.