2.4 Construction Estimating, Markup & Bid Preparation
Key Takeaways
- A complete HVAC estimate is built from five direct-cost buckets - material, labor, labor burden, equipment, and subcontracts - before any overhead or profit is added.
- Markup and margin are different arithmetic: markup is measured against cost, margin against selling price, and adding a 20% markup produces only a 16.7% gross margin.
- To hit a target gross margin, divide total cost by (1 minus the margin), so $10,000 of cost at a 20% target margin must be sold for $12,500, a 25% markup.
- Labor burden - FICA, FUTA, SUTA, workers compensation, general liability, and benefits - typically adds 25% to 45% on top of base wages and must be inside the estimate, not in overhead.
- Lump sum, unit price, cost plus a fee, guaranteed maximum price, and time and material contracts shift cost risk differently, and the estimating method has to match the contract type.
2.4 Construction Estimating, Markup & Bid Preparation
[!IMPORTANT] Why the exam cares: Estimating is one of the eighteen scored subject areas on the Alabama Heating and Air Conditioning examination. The questions are arithmetic, not opinion - they ask you to separate direct cost from overhead, to apply a markup correctly, or to recognize which contract type puts the cost overrun on the contractor. The single most-missed idea in the whole subject is the difference between markup and margin.
An estimate is a prediction of cost. A bid is a price. Contractors fail when they treat the two as the same number. This section walks the estimate from takeoff through the priced proposal.
Step 1: The Quantity Takeoff
The takeoff is a measured count of everything the job consumes, produced from plans, specifications, and a site survey - never from memory.
- Measure in the unit you buy in. Duct board and sheet metal are taken off in square feet, refrigerant line set and flex duct in linear feet, registers and grilles in each, insulation in square feet of surface.
- Take off by system, not by trip. List the condensing unit, air handler or furnace, coil, line set, pad, disconnect, whip, thermostat, filter cabinet, plenums, trunks, branches, boots, grilles, condensate line, float switch, and permits as separate lines. A single missing $180 float switch on 40 changeouts is $7,200 of unbilled cost.
- Do not net out waste. Add a waste and shrink allowance - commonly 5% to 10% on sheet metal, flex, and insulation.
- Record assumptions on the estimate sheet. Every assumption that later turns out to be wrong is a change order only if you wrote it down.
Step 2: The Five Direct-Cost Buckets
| Bucket | What it contains | Common pricing source |
|---|---|---|
| Material | Equipment, duct, fittings, refrigerant, controls, fasteners, sealants | Current supplier quotes; hold quotes in writing |
| Labor | Installer and helper hours from labor units | Historic productivity, then published labor units |
| Labor burden | Employer payroll taxes, workers compensation, liability, benefits | Computed as a percentage of base wage |
| Equipment | Lift rental, crane, brake, vacuum pump, recovery machine, truck cost | Rental rate or internal ownership rate |
| Subcontracts | Electrical, crane, structural, drywall patch, crane rigging | Written sub quotes with scope attached |
Everything else - office rent, estimator salary, dispatcher, advertising, insurance on the building, owner salary - is overhead and is recovered by markup, not by burying it in a labor rate.
Step 3: Labor Units and Labor Burden
A labor unit is the number of installer hours a task historically takes. Once the hours are known, the cost is hours x fully burdened hourly rate.
Labor burden is the difference between what an employee is paid and what the employee costs. For a $25.00/hour Alabama installer, a representative burden build-up looks like this:
| Burden component | Rate applied | Cost per hour |
|---|---|---|
| Social Security and Medicare (FICA employer share) | 7.65% | $1.91 |
| Federal unemployment (FUTA, net of state credit) | 0.6% on the first $7,000 | $0.02 |
| Alabama unemployment (SUTA, $8,000 wage base) | example 2.7% of the $8,000 base | $0.10 |
| Workers compensation (HVAC class code) | example 6.2% of payroll | $1.55 |
| General liability allocated to payroll | example 2.1% of payroll | $0.52 |
| Health insurance, paid time off, training, uniforms | fixed dollars per hour | $4.00 |
| Fully burdened cost | $33.10 per hour (a 32.4% burden) |
A contractor who bids labor at the $25.00 base wage loses $8.10 every hour worked and will not see it until the year-end financial statement.
Step 4: Markup Is Not Margin
This is the arithmetic the exam tests.
Markup is measured against cost; margin is measured against the selling price. Because price is always larger than cost, the margin percentage is always the smaller of the two numbers.
| Applied markup | Selling price on $10,000 cost | Resulting gross margin |
|---|---|---|
| 10% | $11,000 | 9.1% |
| 20% | $12,000 | 16.7% |
| 25% | $12,500 | 20.0% |
| 43% | $14,300 | 30.1% |
| 50% | $15,000 | 33.3% |
To price from a target margin, do not multiply - divide:
A contractor who wants a 30% gross margin on $10,000 of cost must sell at $10,000 / 0.70 = $14,286, which is a 42.9% markup. Adding "30%" to cost yields $13,000 and a 23.1% margin - a $1,286 shortfall on one job.
Step 5: Overhead Recovery, Contingency and the Final Price
- Overhead recovery is normally expressed as a percentage of direct cost or of revenue. If annual overhead is $240,000 and expected annual revenue is $1,200,000, overhead is 20% of revenue and every bid must carry it.
- Contingency covers identified but unquantified risk - unknown attic access, asbestos-wrapped duct, hidden framing. It is not a substitute for a complete takeoff.
- Escalation protects long-lead equipment quotes. Written supplier quotes should state a firm-price period, and the proposal should mirror it.
- Bid errors: a mathematical mistake discovered before award can often be withdrawn; after award, the contractor is generally bound. Double-check extensions and unit conversions before the bid is delivered.
Step 6: Match the Estimate to the Contract Type
| Contract type | Who carries cost overrun risk | Best used when |
|---|---|---|
| Lump sum (stipulated sum) | Contractor | Scope is fully defined by drawings and specs |
| Unit price | Shared - owner pays for actual quantities | Quantities are uncertain but unit work is repetitive |
| Cost plus a fee | Owner | Scope cannot be defined at signing, emergency work |
| Guaranteed maximum price (GMP) | Contractor above the cap, owner below | Owner wants open books but a ceiling |
| Time and material (T&M) | Owner | Service, diagnostics, and small repairs |
Worked Example: Residential Changeout
A 3-ton gas furnace and coil changeout in Hoover:
- Material: equipment $3,400, line set and fittings $260, plenum and transitions $180, thermostat $140, permit $85 = $4,065
- Labor: two technicians, 12 hours each = 24 hours at $33.10 fully burdened = $794.40
- Equipment: recovery machine, vacuum pump, brake allocation = $60
- Subcontract: none
- Total direct cost = $4,919.40
The company needs a 35% gross margin:
Rounded to $7,570, that is a 53.8% markup on cost and a 35.0% gross margin on price. Selling at cost plus 35% would have produced $6,641 and only a 25.9% margin.
An HVAC contractor computes total direct cost on a light commercial rooftop replacement at $18,000 and wants to earn a 25% gross margin. What selling price achieves that margin, and what markup percentage does it represent?
An Alabama installer is paid a base wage of $24.00 per hour. Employer FICA is 7.65%, workers compensation is 6% of payroll, allocated general liability is 2%, and benefits add a flat $3.60 per hour. Ignoring unemployment taxes, what is the approximate fully burdened labor cost per hour?
A public school district cannot define the full scope of a mechanical retrofit at signing but insists on a ceiling it will not exceed. Which contract type places the cost of an overrun above that ceiling on the contractor while letting the owner keep any savings below it?