HVAC Estimating: Ductwork, Equipment, and Piping Quantification

By Waqas Malik, CPE

HVAC estimating involves quantifying complex mechanical systems that often represent the largest MEP trade cost. From large rooftop units to intricate ductwork distribution, accuracy is essential.

Division 23 Scope

CSI Division 23 — HVAC covers:

23 05 00 — Common Work Results for HVAC
23 10 00 — Facility Fuel Systems
23 20 00 — HVAC Piping and Pumps
23 30 00 — HVAC Air Distribution (ductwork)
23 40 00 — HVAC Equipment (AHUs, chillers, boilers)
23 50 00 — Central Heating and Cooling
23 70 00 — Central HVAC Equipment

Ductwork Takeoff

Sheet Metal Duct

Measure linear footage by gauge (24-ga to 16-ga based on size)
Rectangular: width × height dimensions
Round: diameter
Separate supply, return, exhaust, and fresh air

Fittings

Elbows, transitions, tees, offsets, reducers
Volume dampers, fire dampers, smoke dampers
Access doors, turning vanes, flexible connections

Duct Accessories

Diffusers, registers, grilles by CFM rating
Terminal units (VAV boxes, fan-powered boxes)
Reheat coils (hot water or electric)

Equipment Pricing

Equipment	Typical Capacity	Cost Range
Rooftop unit	10-50 tons	$8,000-$50,000
Air handler	5,000-40,000 CFM	$15,000-$100,000
Chiller (air-cooled)	100-500 tons	$80,000-$400,000
Boiler (condensing)	500-5,000 MBH	$15,000-$80,000
VAV box	200-4,000 CFM	$500-$2,500

Labor Productivity

SKM (Sheet Metal) Association standards:

Task	Hours per Unit
Duct (up to 12” round)	2.5 hrs/100 LB
Duct (rectangular, 24” wide)	3.0 hrs/100 LB
Diffuser installation	0.5 hrs each
VAV box (ceiling-mounted)	6 hrs each
RTU (curb-mounted)	16-24 hrs each

For complete HVAC estimating with MCAA labor unit application, contact F&K Estimatings. Our mechanical estimators handle projects from small retail to industrial process systems.