Ductwork & air distribution
Rectangular, round, and flex duct quantified by size, gauge, and insulation class off the mechanical plans — with fittings, dampers, and turning vanes counted, not averaged.
HVAC EstimatingMechanical estimates
Mechanical estimates
that hold up at commissioning.
Your Buildbid agent reads the mechanical drawings, equipment schedules, and specs, then returns ductwork, piping, and equipment — priced at your rates, in minutes.
Ductwork by size and gaugeEquipment at your vendor quotesLoad-based pricing checks
What the agent takes off. Every mechanical line.
Quantities come off your drawings and specs. Costs come from your book. Nothing is filled in from a per-ton average.
Equipment schedules
RTUs, AHUs, chillers, boilers, VRF systems, and split systems matched to the schedule line by line, priced at your vendor quotes and lead times.
Load-based pricing
Tonnage and capacity checks against the load calcs, so undersized or oversized equipment gets caught at estimate time — not at commissioning.
Piping & hydronics
Chilled water, heating water, refrigerant, and condensate piping by material and diameter, with insulation, valves, and accessories itemized separately.
Air terminals & devices
VAV boxes, diffusers, grilles, registers, and exhaust fans counted per floor and per zone, tied back to the airflow schedule they serve.
Controls & automation
Thermostats, sensors, actuators, and BAS points scoped from the controls drawings and sequences, so the controls allowance stops being a guess.
Labor & crew productivity
Sheet metal, piping, and startup hours modeled at your crew's production rates — not a national average that flattens your margin.
Testing, balancing & commissioning
TAB, duct leakage testing, and commissioning support surfaced as line items you decide on, instead of scope that shows up after the award.
What you get back
Quantity takeoff
Every duct, pipe, and equipment item with units, locations, and the drawing it came from.
Equipment comparison
Schedule quantities against your vendor quotes, so substitutions and lead times are visible before you commit.
Labor hours by activity
Hours per system and per floor, so you can check the schedule against the number.
Your rates, your markup
Material, equipment, and sub rates you set — applied the same way on every bid.
And the summary: a bid you can defend line by line, out the door before the addendum deadline.
Where HVAC bids leak money.
Four assumptions that decide whether a mechanical bid makes margin. Your agent makes each one explicit, priced, and visible before you submit.
Ductwork by the pound
A pounds-per-square-foot rule either gives away sheet metal on a simple job or loses the bid on a complex one.
Equipment substitutions
An alternate unit with different weights, curbs, or electrical needs changes three other trades' scope — and your number.
Controls scope creep
Sequences in the specs that never made it into the estimate come back as a change order you eat.
TAB and commissioning
Balancing and testing are in Division 23. They should be in the price, not absorbed as overhead.
How it works
1
We build your agent
Tell us how you price mechanical work — your duct assemblies, labor units, vendor discounts, and markups. We train a custom AI agent on your way of bidding.
2
Drop in your plans
Upload the mechanical drawings, equipment schedules, and specs. Your agent reads them and builds a detailed HVAC takeoff.
3
Get the estimate fast
Review quantities, labor hours, and a complete line-item estimate in a fraction of the usual time — then tweak, approve, and send the bid.
How to estimate HVAC bids
Bidding HVAC jobs well means pricing ductwork, equipment, and labor from the drawings — not from rules of thumb. Here is a practical process for mechanical contractors.
- 01
Read the equipment schedules first
List every RTU, AHU, split system, fan, and terminal unit with tonnage, CFM, and options. Equipment is often the largest single cost, so get vendor quotes early.
- 02
Take off ductwork by size and gauge
Measure duct by run and size, convert to pounds by gauge, and count fittings separately. Fittings and transitions carry far more labor than straight duct.
- 03
Count air devices and accessories
Diffusers, grilles, registers, dampers, and flex connections come straight off the plans. Match each to the air device schedule.
- 04
Price piping and hydronics
Measure refrigerant, condensate, and hydronic piping by size and material, then add insulation, hangers, and valves.
- 05
Apply labor units by activity
Turn every quantity into hours with your labor units — hanging duct, setting equipment, piping, and startup — then adjust for height and access.
- 06
Don't forget controls, TAB, and commissioning
Controls, test-and-balance, and commissioning are frequently subcontracted or forgotten. Carry a number or a clear exclusion for each.
Should I price HVAC by the ton?
Price per ton is a useful sanity check, but bids should be built from the takeoff. Two jobs with the same tonnage can have very different duct and piping scope.
What do HVAC estimators miss most often?
Duct fittings, equipment substitutions with different connections, and controls scope that grows after the award.
Buildbid.ai builds a custom AI agent that does these steps on your plans, at your rates, so every HVAC bid goes out faster and more consistent.
Read the full HVAC estimating guide →Ready to put an AI agent
on your mechanical estimates?
Send us a set of mechanical drawings and how you price ductwork today. We'll show you the takeoff and the number a custom Buildbid agent comes back with.