Commercial HVAC Project Plan

A preliminary project scope built from your quote inputs — duct layout and sizing, equipment schedule, and a material takeoff priced for your region.

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Project Inputs
Adjust any input to regenerate the plan.

Includes duct layout, equipment, materials, and code requirements — ready to send to contractors.

Project Summary — U.S. National Average
Rooftop Units (RTUs) · Medium ducts (12"–24") · regional index 1.00× (Baseline mechanical cost index)
Conditioned Area
10,000 sq ft
Design Airflow
10,000 CFM

at 1.0 CFM/sq ft

Cooling Capacity
28.6 tons
Control Zones
3

VAV terminals

Total installed cost range

$140,000$220,000

14.0022.00 per sq ft · project-size factor 1.00×

Duct Layout & Sizing
Trunk, riser, runout, return, outside-air, and exhaust runs sized to ASHRAE velocity targets.
TagRunCFMRoundRectangularVelocityLengthGaugeInsulation
SA-MSupply main trunk (from unit discharge)5,00026"30" × 20"1,356 fpm120 ft22 gaR-6 external wrap
SA-BSupply sub-trunk / riser branch2,50020"24" × 16"1,146 fpm160 ft22 gaR-6 external wrap
SA-RZone runouts to VAV terminals (3 zones)3,33328"33" × 22"779 fpm105 ft20 gaR-6 external wrap
RA-MReturn air main4,25028"33" × 22"994 fpm100 ft20 gaNone required
OAOutside air / ventilation duct2,00020"24" × 16"917 fpm50 ft22 gaR-8 external wrap
EAExhaust air duct1,20014"17" × 11"1,123 fpm60 ft24 gaNone required
Equipment List
Installed unit pricing adjusted for U.S. National Average.
TagDescriptionQtyCapacityUnit CostExtended
RTU-1..2Rooftop Units (RTUs)214.3 tons$21,450$34,320$42,900$68,640
VAV-1..nVAV terminal units with hot-water/electric reheat33,333 CFM$1,100$1,900$3,300$5,700
EF-1..nExhaust fans (restroom / general building exhaust)11,200 CFM$900$1,800$900$1,800
DDCDDC controls, sensors, and BAS integration1$16,000$32,000$16,000$32,000
Equipment subtotal$63,100$108,140
Materials by Region
Takeoff quantities priced at 1.00× the national mechanical cost index.
Material / ScopeQtyUnit CostExtended
Galvanized sheet metal ductwork (fabricated & installed)Medium ducts (12"–24"); 595 linear ft total5,243 lb$6.50 – $11.00$34,080$57,673
Duct insulation — R-6 external wrapSupply and outside-air ducts4,958 sq ft$2.10 – $3.60$10,412$17,849
Flexible duct runouts to diffusers8 ft max per ASHRAE / IECC limits18 ft$5.00 – $9.00$90$162
Supply diffusers, returns, and grillesLay-in and surface-mount mix40 ea$95.00 – $190.00$3,800$7,600
Volume dampers, fire/smoke dampers, and access doorsFire dampers at rated assemblies8 ea$210.00 – $640.00$1,680$5,120
Hangers, seismic bracing, sealant, and fastenersSMACNA hanger spacing595 ft$3.20 – $6.00$1,904$3,570
Roof curbs, structural steel, and riggingPrefabricated curbs2 ea$2200.00 – $5200.00$4,400$10,400
Testing, adjusting & balancing (TAB) and commissioningIndependent TAB agency10,000 sq ft$0.35 – $0.75$3,500$7,500
Materials & installation subtotal$59,865$109,874
Code Compliance — U.S. National Average
Adopted codes: IMC / IECC (edition varies by jurisdiction). Confirm the exact edition with the authority having jurisdiction before permitting.

ASHRAE & SMACNA Standards

ASHRAE 62.1Ventilation for Acceptable Indoor Air Quality
Outdoor air rates by Ventilation Rate Procedure (typically 5 cfm/person + 0.06 cfm/sq ft for offices); provide OA measurement and minimum-position control at each air handler.
ASHRAE 90.1Energy Standard for Buildings
Duct leakage class, insulation minimums (R-6 concealed / R-8 exterior), fan power limits, economizers on most cooling units, and DDC controls with setback scheduling.
ASHRAE 55Thermal Environmental Conditions
Maintain occupied-zone comfort envelope; supply diffuser throw and terminal velocities under 50 fpm in the occupied zone.
ASHRAE 111 / SMACNATesting, Adjusting & Balancing
Independent TAB agency to balance all systems within ±10% of design airflow; document duct pressure class and leakage test results.
SMACNA HVAC-DCSDuct Construction Standards
Gauge, reinforcement, sealing class, and hanger spacing per pressure class; seal class A on all supply ductwork.

NFPA & Life Safety

NFPA 90AAir Conditioning & Ventilating Systems
Fire dampers at rated walls/floors, smoke dampers at smoke barriers, duct materials with flame spread ≤25 / smoke developed ≤50, and smoke detectors in supply systems over 2,000 cfm.
NFPA 96Commercial Cooking Ventilation
Where kitchen hoods are present: welded liquid-tight grease duct, listed enclosure or 2-hour shaft, cleanouts, and hood suppression interlock.
NFPA 72Fire Alarm & Signaling Code
Duct smoke detectors must shut down the unit and report to the fire alarm panel; provide remote test/annunciator stations.
NFPA 101Life Safety Code
Ductwork and equipment must not compromise egress enclosures; stair pressurization and smoke-control interfaces where required.
NFPA 70 (NEC)National Electrical Code
Disconnects within sight of equipment, GFCI service receptacle at rooftop units, and proper working clearances.

Local & Regional Requirements

IMCInternational Mechanical Code
Duct construction, combustion air, exhaust rates, and access clearances per the locally adopted IMC edition.
IECC (Commercial)Energy Code
Duct sealing and leakage testing, insulation, economizers, and commissioning documentation for systems over 480,000 Btu/h.

Project-Specific Compliance Notes

  • Design outdoor air: approximately 600 CFM minimum per ASHRAE 62.1 area-based rate (add occupant-based component).
  • Supply system exceeds 2,000 CFM — duct smoke detector required downstream of filters per NFPA 90A.
  • Building over 10,000 sq ft — ASHRAE 90.1 / IECC commissioning and a commissioning report are required.
  • Confirm the code edition adopted by the local AHJ before permitting; amendments frequently differ from the model code.
Local Contractors — U.S. National Average
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Important Disclaimer

This calculator is for preliminary design guidance only. Final duct sizing, construction, and installation must be performed by qualified professionals and comply with applicable codes and standards.