A/B Testing in Cold Emails
Every marketer knows the feeling you’ve crafted the perfect email, hit Send, and waited… only to wonder, why didn’t more people reply?
The truth is, even the best emails fail when we rely on assumptions instead of data.
That’s where A/B testing and strategic email marketing come in.
In this article, you’ll learn:
- What A/B testing really means (and why it’s a must)
- When and why to use email marketing
- Tips for writing cold outreach emails that actually convert
- Two real email examples (A vs B) for inspiration
- How to publish and automate everything inside HubSpot
1️⃣ What Is A/B Testing — and Why It Matters
A/B testing is simply comparing two versions of the same email to see which performs better.
You can test:
- Subject lines
- CTA buttons
- Tone of voice (formal vs casual)
- Visuals or structure
In HubSpot, this is built-in. You send Version A to half your audience, Version B to the other half, and HubSpot reports which one wins based on open or click rates.
🎯 Goal: Take the guesswork out of outreach and continuously improve results using real data.
2️⃣ When & Why to Use Email Marketing
Email remains the highest-ROI channel in digital marketing — $36 return for every $1 spent.
You should use email when you need to:
- Nurture leads after they visit your site or download a resource
- Re-engage prospects who went cold after initial contact
- Educate customers through newsletters or success stories
- Convert cold leads into meetings through personalized outreach
📈 Pro Tip: Segment your lists by behavior (visitors, form-fills, free-trial users) so each email feels tailored — not templated.
3️⃣ Tips & Tricks for Writing Cold Outreach Emails
Here’s what separates emails that get ignored from those that spark action:
- Personalize your hook — mention something specific about the recipient (their company, city, or latest post).
- Be clear and concise — under 250 words; get to the point quickly.
- Use one strong CTA — “Book a 15-min call” or “Reply YES,” never both.
- Leverage psychology — Cialdini’s persuasion principles:
- Reciprocity → Give value first.
- Social Proof → Show others’ success.
- Authority → Demonstrate expertise.
- Scarcity → Limited offer or slots.
- Reciprocity → Give value first.
- Optimize subject lines — 10-40 characters, curiosity + clarity.
- Follow up — most replies come after the second or third email.
4️⃣ Real A/B Test Example
Below are two versions of a real outreach email we used for a campaign.
✉️ Email A
Subject:
“How the top Spanish schools in Barcelona fill their classes every semester”
Body:
Hi ,
We’ve helped several leading language schools in Barcelona increase student sign-ups by over 40% using smart digital funnels — and I thought you might find our latest breakdown useful.
It’s a short read that shows exactly how schools are turning Google searches and ChatGPT queries into new enrollments — without spending more on ads.
👉 See the full guide here
If you find it helpful, I’d love to offer a quick free audit of your current funnel and share a few ideas tailored to your school.
Warm regards,
Founder, The True Reach
📍Barcelona | www.thetruereach.com
✉️ Email B
Subject:
“We helped 3 schools fill their September courses — yours could be next.”
Body:
Hi ,
Enrollment season is almost here — and the top schools we work with are already hitting their numbers.
We just published a case study showing how one Barcelona school filled all 8 group classes through a simple marketing funnel (no paid ads, just smarter content and automation).
➡️ Read the case study before enrollment closes
We’re offering 3 free strategy calls this week to review funnels for language schools. Would you like to reserve one?
Best,
The True Reach
📍Barcelona | www.thetruereach.com