We talk to HVAC contractors, plumbers, and electricians every week who run Google Ads campaigns that cost more to manage than the jobs they generate. The problem isn't Google—it's strategy. With $500/month, you're not going to out-spend your competitors. You're going to out-think them. We've helped local service businesses cut cost-per-lead in half by doing three things differently: ruthlessly narrow keywords, geofence aggressively, and measure backwards from job profitability.
Start with Job Economics, Not Vanity Metrics
Before you touch Google Ads, know your numbers. If a typical job is worth $800 profit and your close rate is 30%, a lead is worth $240 to you max. If your average cost-per-click is $3 and it takes 4 clicks to get a lead, you're spending $12 per lead—solid. If you're spending $60 per lead because you're bidding on "emergency plumber near me," you're underwater. Imagine a water damage restoration company whose modest monthly budget actually turns a profit—only because someone accidentally set the location radius to 5 miles instead of 50. The lesson is real: tighten your geography first.
- Calculate your actual job profit (revenue minus labor, parts, overhead)
- Divide by your documented close rate to get lead value
- Set max cost-per-lead at 10-15% of lead value
- Track which lead source converts to which job type
Use Long-Tail Keywords and Negative Keywords Aggressively
Broad match on "plumber" will drain your budget in a week. You'll be paying for searches from people three states away, calls at 2am you can't service, and DIY searches. Set every account to phrase match or exact match only—no broad or broad match modifier. Your budget is too small to educate Google's algorithm. Instead, bid on what converts: "water heater replacement [your city]", "slab leak detection $$$", "emergency toilet repair on weekend". These keywords get 20-30 searches/month instead of 500, but they convert at 40-50% vs 8% on generic terms.
Negative keywords are where budget actually gets saved. Picture a roofing contractor unknowingly spending a chunk of budget on "roofing schools", "roofing jobs", and "free roofing estimates". Add 40 negatives in week one—school, job, employment, free, DIY, cost, estimate without phone call trigger—and spend-per-qualified-lead drops immediately.
Your $500/month is better spent on 50 ultra-qualified searches at $10 each than on 1,000 semi-qualified searches at $0.50 each. Math wins.
Build Separate Campaigns by Service Type and Margin
If you offer 4 services (heating, cooling, plumbing, electrical), you need 4 campaigns with different budgets aligned to profitability. Heat pump installs have 45% margins; emergency callouts have 65%. Spend proportionally. Picture an HVAC company in Minnesota allocating budget evenly across all services—chasing low-margin emergency calls while high-margin seasonal installs get no impressions. Rebalance the daily budgets toward the high-margin campaigns and every dollar of spend starts working harder.
- Identify your 2-3 highest-margin services
- Allocate 60% of budget to those services
- Use day-parting: stop ads at 9pm or on days you can't service calls
- Test one offer per campaign: "$99 diagnostic", "free estimate", "same-day service"
Measure Everything, Optimize Weekly
With $500/month, you don't have time for monthly reviews. Check your Google Ads account every Friday. Kill keywords with cost-per-lead above your threshold—even if they only spent $30 that week. Pause any keyword that got 15+ clicks with zero conversions. Move budget from 6% CTR keywords to 12% CTR keywords. Imagine a plumbing company in Austin keeping a keyword alive for sentimental reasons (it brought their first job) while it quietly racks up months of clicks and zero new jobs. Pause it, reallocate the budget to a keyword that's actually converting, and that single change pays for the whole weekly review habit.
Want this working inside your own stack?
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