Hiring a service manager who can't actually run a 30-tech service department is the most expensive mis-hire in commercial HVAC. Here's how to vet correctly.
They own dispatch, T&M vs. PM mix, technician utilization, customer retention, agreement renewals, technician training, and gross margin on every work order. The strongest service managers can recite their last quarter's billable utilization, agreement renewal rate, and average ticket size from memory. The weak ones describe their role in feelings.
"Walk me through how you'd take a service department from 65% billable utilization to 78% over two quarters." The answer should reference dispatch board discipline, drive-time routing, after-hours rotation design, technician skills matrix matched to call type, and the conversation they'd have with techs who chronically log low utilization. Vague answers about "accountability" are a fail.
Give them a real scenario: a 250-ton water-cooled chiller at a hospital that's short-cycling on low evap temp during a heat wave. Ask what they'd tell the lead tech to check first, in what order, and what they'd communicate to the customer's facilities director. You're not testing whether they can troubleshoot — you're testing whether they can run a tech through troubleshooting and translate the work to a non-technical buyer.
"What's a healthy gross margin on a PM agreement vs. a demand T&M call in your market?" The honest answer in 2026: PM agreements 35–45%, demand T&M 50–60%, project work 25–35%. If they don't know their own numbers, they're not running the department — someone above them is.
Ask: "Tell me about the last tech you had to let go and the last one you promoted." Listen for specifics — performance data, conversations, timeline. Service managers who can't name specific techs and specific decisions are usually titles, not operators. Also ask: "What's your annual technician turnover rate, and what's your industry's average?" Best-in-class commercial HVAC service shops run 12–18% annual tech turnover; industry average is closer to 25%.
Two former direct-report techs (not handpicked friends) and one former general manager. Ask the techs: "Would you go work for him again, and why or why not?" Ask the GM: "What was his department's billable utilization trend, and what was your gross margin on service?" Both answers tell you more than the candidate ever will.
Blaming techs for performance problems. Service managers own their team's outcomes. Candidates who describe past failures as "I had a bad bench" rather than "I should have coached harder or recruited better" will do the same thing in your shop.