HVAC Install Bid Calculator: Loaded Labor, Overhead & Markup Explained
Why Gut-Feel HVAC Bids Lose Money
Most HVAC bids start with material cost plus a flat labor rate, then a markup percentage slapped on top. The problem: the labor rate quoted is almost never the true cost of that technician standing on the job site. Wages are only part of it.
Step 1: Calculate Loaded Labor Cost (Burden)
Say a lead installer earns $28/hour. Add:
- Payroll taxes (FICA, FUTA/SUTA): ~10% = $2.80
- Workers' comp (HVAC class code often 5-10%): ~7% = $1.96
- Health insurance/benefits: $3.50/hour
- Paid time off allocation: $1.20/hour
Loaded labor rate = $28 + $2.80 + $1.96 + $3.50 + $1.20 = $37.46/hour — not $28. That's a 34% burden most bids never see.
Step 2: Add Truck and Tool Overhead
Every labor hour on a job also carries a share of fixed costs: truck payment, fuel, insurance, tool depreciation, phone, and shop overhead. If your shop spends $18,000/month on overhead and your two-tech crew logs 320 billable hours/month combined:
Overhead per labor hour = $18,000 / 320 = $56.25/hour
Add this to loaded labor: $37.46 + $56.25 = $93.71/hour true cost per tech-hour before a single wrench turns for profit.
Step 3: Price Materials at Landed Cost
A condenser unit priced at $2,400 wholesale isn't $2,400 to you once you factor delivery fees, restocking risk on returns, and tax if not resold. Add 3-5% landed cost adjustment: $2,400 × 1.04 = $2,496.
Step 4: Build the Job Cost Before Markup
Example install: 14 labor hours, one condenser + air handler at $2,496 + $1,850 = $4,346 in materials.
- Labor cost: 14 × $93.71 = $1,311.94
- Material cost: $4,346
- Total loaded job cost: $5,657.94
Step 5: Apply Markup to Cost, Not Price
A common mistake: applying a 20% margin as if it were a 20% markup. If you want a 20% margin, divide, don't multiply:
Bid price = Cost / (1 - margin) = $5,657.94 / (1 - 0.20) = $7,072.43
Multiplying by 1.20 instead would give $6,789.53 — a bid that looks fine but actually delivers only a 16.5% margin once costs are subtracted.
Step 6: Reserve for Callback Labor
HVAC installs commonly return 3-5% of jobs for warranty adjustments — refrigerant leaks, thermostat wiring, airflow balancing. Adding a 4% callback reserve to loaded labor cost before markup keeps that risk priced in rather than eaten later.
What a Spreadsheet Needs to Compute
A working bid calculator needs to run these numbers automatically for every job: fully loaded labor rate (wage + taxes + insurance + benefits), per-hour overhead allocation from monthly fixed costs and billable hour volume, landed material cost with tax and delivery, a callback labor reserve percentage, and margin-based (not markup-based) price conversion — producing one bid number that reflects true job cost, not a guess dressed up as a price.