Plumbing Water-Heater Replacement Campaign: 28 Replacements From 1,400 Households

The challenge

Granite State Plumbing was a service-call business — phone rings, tech rolls, invoice closes. The owner had grown to 5 techs purely on emergency response and word-of-mouth. The CRM held 4,200 past-customer households, and a quick filter showed 1,400 of them had a water heater installed by Granite State 8+ years ago. Average residential tank water heater dies between 10-12 years; that 1,400-household pool was a slow-rolling time bomb of failures heading toward the competitor with the fastest response.

The owner had never run proactive marketing. Every replacement the company had ever sold was a panic-call after a tank leaked and flooded a basement. Those calls were profitable, but they were also chaotic — same-day rush installs, often at premium pricing the customer resented, and the customer base ended up with a story about their plumber being expensive rather than helpful.

Two big-box installers had begun direct-mailing the same neighborhood with $899 water-heater quotes. The owner knew his $1,400 quality-install was justified — better tank, code-current install, lifetime workmanship — but he had no marketing channel to make that case before the panic call. He needed to land in the household before the failure, not after.

The PostKnock approach

Playbook used: Equipment Age Replacement

We pulled the CRM's install records, filtered to tank water heaters installed 8+ years ago at residential addresses, and loaded the 1,400-household list into PostKnock's Equipment Age Replacement playbook. The framing was deliberately educational rather than promotional: "Your water heater is X years old. Here's what happens at year 10. Here's what we recommend." — not "$200 off!". For a high-trust home-services category, education-led copy converts better than discount-led.

Wave 1 was a 6x9 postcard with a personalized line referencing the install year ("We installed your water heater in 2017 — it's heading into the high-failure window") and a single CTA: book a free 15-minute proactive inspection. The card included a QR code with the pre-filled service form, a callback number, and a small breakdown of "failure signs to watch for" that read as homeowner education. The card image was the actual brand of unit installed when available — a personalization touch the playbook supports.

Three days after Wave 1, the dispatcher worked the non-responder list with a soft script: "Just checking in — Greg installed your water heater 9 years ago, wanted to see if you'd noticed any issues." Wave 2 dropped at week 4 with creative emphasizing planned-replacement savings ($300-500 cheaper than emergency-replacement on average). Total: 2,800 pieces, ~280 outbound calls, 8-week campaign window aligned with fall heating-season concerns.

Campaign timeline

Week 0

CRM filter on tank-water-heater installs 8+ yrs old, list scrub, 2 creatives proofed.

Week 1

Wave 1 drops (1,400 cards). Install-year personalization.

Week 2

Dispatcher runs follow-up calls. 175 dials, 88 connects.

Week 3-4

Inspections book. 38 free 15-minute inspections scheduled.

Week 4

Wave 2 drops (1,400 cards). Planned-replacement savings angle.

Week 5-6

Inspection conversions. 22 inspections progress to scheduled replacements.

Week 7-8

Final tally: 28 water-heater replacements completed or scheduled.

Results

Twenty-eight water-heater replacements on 1,400 unique households is a 2.0% response rate, which lands at the high end of the 1-3% range for plumbing direct mail (and dramatically above blanket-mail benchmarks because the list was tightly filtered to install-history). Average replacement ticket at this practice is $2,100 (mid-line tank, code-current install, warranty), giving us $58,800 in directly-booked revenue.

Total campaign cost ran $4,180 — $1,680 in postcards (2,800 at $0.60), $297 in PostKnock Pro plan for 3 months, and $2,203 in dispatcher follow-up labor. Net first-year ROI of 14.1x is the visible number — the bigger return is the 9 households who declined replacement now but agreed to an annual reminder, plus the 38 first-time inspections that opened doors for unrelated plumbing work the techs flagged. Three of those flagged jobs converted within the campaign window for an additional $4,200 not counted in the headline ROI.

“I never thought of myself as a marketer. I thought I'd be saving customers from the 2 a.m. flooded-basement disaster. Turns out the customers really wanted to be saved from it.”

— Owner, Granite State Plumbing (composite illustration)

What we’d do differently

• Install-year personalization was the single biggest driver. Generic "is your water heater old?" cards from competitors were ignored; ours that said "we installed yours in 2017" got read.
• We initially priced the inspection at $49. Switching to free for the campaign tripled response. Discount-versus-free thresholds matter more than dollar amounts in trust-based home services.
• Two replacements were undercut by big-box quotes after the inspection. Next campaign we'd include a "why our install costs more" sidebar on the inspection-followup leave-behind to pre-empt the price comparison.