F&K Estimatings
Commercial rooftop HVAC unit

HVAC Estimating that Catches the Scope Gaps.

Mechanical estimating isn't just counting diffusers. It's understanding SMACNA pressure classes, chilled water loops, and the hidden labor in BAS integration. We deliver bid packages that protect your shop.

Real-World Sheet Metal & Piping Intelligence

A 2% error on a 100,000-pound sheet metal job is a massive hit to your margin. Our mechanical takeoff process is designed to account for the real-world friction of HVAC installation. We read the spec book first. If the engineer calls for 2-inch dual-density duct liner on the first 20 feet of all RTU supply drops, we ensure that specific material and labor premium is captured in the bid.

Common HVAC / Mechanical Scope Gap
Risk Impact: $250 - $400 per location (Labor + Material)

Missed: Fire & Smoke Damper Access Doors

Estimators frequently count the fire dampers shown on the mechanical plan but forget that code requires an access door in the ductwork to test and reset the damper. On a hospital project with 150 dampers, missing the access doors and the coordination labor can wipe out $50,000 in profit.

How We Catch It

We cross-reference the mechanical plans against the architectural life-safety plans. Whenever a duct penetrates a fire-rated wall, we automatically add the required fire damper, the breakaway connections, the duct access door, and the labor to coordinate the inspection.

Hydronic Piping & Central Plants

For chilled water and heating hot water systems, we trace every inch of welded steel, grooved mechanical, or copper pipe. We account for the specialized labor required for welding or Victaulic roll-grooving. We also break out the critical accessories: isolation valves, strainers, triple-duty valves, suction diffusers, and the required thicknesses of closed-cell elastomeric or fiberglass pipe insulation.

David Chen
18+ YRS
Preconstruction Expert

David Chen

Lead Mechanical Estimator • Central Plants & Hydronics

"I used to hang duct. I know that installing spiral pipe at 25 feet off a scissor lift takes twice as long as hanging rectangular at 10 feet. We price the labor to match the reality of the field."
ASHRAE MemberFormer Sheet Metal Worker

Typical Mechanical RFI Catches

  • VAV Power: Mechanical schedule shows VAV boxes with electric reheat, but electrical plans show no circuits routed to them.
  • Roof Curbs: RTUs specified, but structural plans don't show the required dunnage or curb supports.
  • Condensate: Split systems shown on interior walls with no clear routing for condensate gravity drains.

The HVAC Precision Protocol

A systematic approach to mechanical takeoffs that captures every duct fitting, control device, and equipment connection.

01

Duct Pressure Class Audit

We verify the SMACNA pressure class for each duct section. High-pressure duct requires TDF/TDC connections and additional stiffeners vs low-pressure spiral.

02

Equipment Schedule Cross-Check

We reconcile the mechanical equipment schedule against plan details. If RTUs are specified but curbs aren't detailed, we flag the gap and price the structural dunnage.

03

Fire & Smoke Damper Log

Every duct penetration through a fire-rated wall is logged with the required damper, access door, and breakaway connection per IBC and NFPA 90A.

04

Controls Integration Map

We map the DDC/BAS sequence of operations against the points matrix, ensuring VAV controllers, temperature sensors, and actuators are fully captured in the bid.

HVAC Estimating Logic FAQ

How do you quantify sheet metal waste?
We don't just use a flat percentage. We calculate sheet metal based on coil widths (48in. or 60in.) and apply specific SMACNA allowance factors for TDC/TDF transverse joints, longitudinal seams, and stiffeners based on the pressure class of the duct.
Do you catch clashes with structural steel?
Yes. During our plan review, if we see a 36x24 medium-pressure trunk line routed through a space with 18-inch bar joists, we immediately flag the constructability issue. We provide this RFI data so you can clarify the scope before you bid.
How do you handle controls (DDC/BAS)?
Controls integration is the #1 area for scope gaps. We read the sequence of operations (SOO) and the points matrix. If the mechanical schedule lists VAVs but the points matrix requires BACnet integration and space temperature sensors, we ensure the wiring, conduit, and programming labor are captured.
Do you estimate refrigerant piping for VRF systems?
Yes. VRF/VRV systems require highly accurate line set lengths to calculate the total refrigerant charge. We trace the suction, liquid, and hot gas lines, calculate the total length, and apply the manufacturer's required charge-per-foot to price the R-410A or R-454B.
Bid-Risk Management

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