Estimating guide · HVAC
How to bid HVAC jobs
HVAC estimates combine expensive equipment with labor-heavy installation. Winning bids price both accurately — equipment from real quotes, labor from real units. Here's how mechanical contractors build an HVAC bid from the drawings.
1. Review the scope and the equipment schedules
Read the mechanical drawings, schedules, and Division 23 specs before taking anything off. List every piece of equipment — rooftop units, air handlers, splits, VRF systems, exhaust fans, VAV boxes — with capacity, CFM, voltage, and options.
Send the schedule to suppliers early. Equipment is often the largest single cost on the job, and lead times may affect your schedule and pricing.
2. Take off ductwork
Measure duct by system and size. Sheet metal is commonly priced by weight: convert rectangular duct to pounds using the gauge required by the specs or SMACNA tables. Round and spiral duct is usually priced by the foot.
Count fittings separately — elbows, transitions, takeoffs, and offsets take far more fabrication and installation labor than straight runs.
- Duct insulation or lining by square foot
- Flex duct and connections to diffusers
- Hangers and supports, especially at high ceilings
- Fire, smoke, and volume dampers
3. Count air devices and accessories
Diffusers, grilles, and registers come straight off the plans and the air device schedule. Count by type and size, and confirm finish and border types so your supplier quote matches.
4. Price piping
Measure refrigerant, condensate, hydronic, and gas piping by size and material. Add fittings, valves, insulation, and supports. On hydronic systems include pumps, expansion tanks, air separators, and chemical treatment.
5. Apply labor units
Convert every quantity to labor hours using your units — per pound of duct, per fitting, per device, per foot of pipe, per piece of equipment. Adjust for working height, access, occupied buildings, and night work.
Add crane picks for rooftop equipment, rigging, and any roof curbs or structural supports in your scope.
6. Carry controls, TAB, startup, and commissioning
Controls, test-and-balance, and commissioning are frequently subcontracted and frequently forgotten. Get quotes or carry a clear exclusion for each, plus startup, training, and warranty.
7. Finish with general conditions and markup
Add permits, supervision, project management, trucks, small tools, and closeout documents. Then apply overhead and profit appropriate to the market and the job's risk.
Frequently asked questions
Should I price HVAC jobs by the ton?
Price per ton is a useful sanity check, but it hides big differences in ductwork and controls. Build the estimate from takeoff and compare to $/ton afterwards.
How is ductwork priced?
Rectangular sheet metal is commonly priced by the pound based on gauge; round and spiral duct is often priced by the linear foot plus fittings.
What do HVAC estimators most often miss?
Fittings, dampers, controls, crane picks, and test-and-balance are the usual gaps.
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