Varitrane Duct Designer

Varitrane Duct Designer logo.

Designing supply duct systems can be tedious... it involves time consuming calculations and requires assumptions about fitting size and performance. VariTrane Duct Designer streamlines this task and improves calculation precision, allowing you to optimize your designs from fan to diffuser and be more productive! The program consists of three applications:

  • Duct Configurator helps you model and size supply duct systems, as well as determine required fan static pressures. Re-size non-critical paths to reduce system first cost while optimizing the system design. Choose between the static regain and equal friction methods of design. Design constant volume or VAV systems with detailed control over diversity. Make VAV box selections directly in the program through a seamless interface with the Trane Official Product Selection System providing highly accurate system pressure and sound analysis. Three different fitting entry methods provide a wide array of choices for making fitting selections. Choose from all available fittings, customize the available fittings, or let the program select lowest loss fittings for the system.
  • Ductulator transforms Trane's popular manual duct sizing and layout calculator into a convenient PC-based tool. Use it to quickly size system components and determine the appropriate nominal duct size for equal friction applications.
  • Fitting Loss Calculator lets you quickly identify the optimal fittings and sizes for each duct section by comparing their efficiency and cost.
These applications, combined with an integral database of accurate performance data for hundreds of ASHRAE and United McGill fittings, let you model new or existing supply duct systems, whether round, rectangular, or flat oval. After you complete your design, print reports with detailed information about all aspects of the duct system, including bill of materials. Screen Shots


duct sizing, static regain, equal friction, fitting loss



Expertise Required

Basic knowledge of duct systems, methodologies, and terms.


Approximately 1000 users worldwide.


Mechanical engineers and system designers in need of accurate duct system modeling capabilities.


Enter data in easy to follow tab formatted interface. The tabs include Main, Fan, Sections, VAV boxes, Diffusers, and Spreadsheet.


VariTrane Duct Designer calculates airflows, velocities, detailed pressure drops, and diversity and produces thirteen different reports. Nine reports show calculation results including Project Summary, Sections, Diffusers, VAV Boxes, Trane Acoustical and Selection Data, Run-out Analysis, and Fitting and Section Bill of Materials. Four reports are dedicated to entered values. The critical path is clearly marked for quick analysis.

Computer Platform

PC-compatible, Windows 9x, NT, ME, XP, Pentium processor, 16 MB RAM (32 MB recommended), 50 MB free hard disk space (120 MB required for TOPSS VAV selection integration).

Programming Language



Ability to optimize design by re-sizing non-critical paths and adjusting for thermal and leakage changes. Make detailed VAV selections with acoustical analysis directly in the program. Ability to make detailed fitting analyses. Model new or existing systems making large-scale changes quickly and easily through the spreadsheet editor.


Does not model return or exhaust ductwork.



Trane Company


3600 Pammel Creek Road
Building 17-1
La Crosse, Wisconsin 54601-7599
United States


(608) 787-3926


(608) 787-3005




Purchase the Distribution Suite, which includes both VariTrane Duct Designer and Trane Pipe Designer, for $595 for a standard single license or $892.50 for a site/LAN license. VariTrane Duct Designer alone costs $495 for a standard single license and $792.50 for a site/LAN license. Call the Support Center to receive special pricing for educational purposes or current promotional discounts. A yearly renewal fee of 23 percent of the purchase price entitles customers to unlimited free phone support, as well as automatic updates and documentation. All Trane C.D.S. software programs have an unconditional 30-day money-back guarantee. Download software updates at our website. Experienced HVAC engineers and specialists support the software Monday through Friday 8 a.m. to 5:30 p.m. On-site training available at Trane headquarters as well as regional training at sites throughout the U.S. or at your office. Contact the C.D.S. Support Center for more information.