Digiduct vs Duct Sizer Calc HVAC

The Digiduct app is a powerful tool designed for HVAC professionals, supporting everything from design calculations to real-time field verification. Built utilizing the equations and recommendations from the ASHRAE Fundamentals – Duct Design chapter, it ensures your calculations are accurate and reliable, saving you time and reducing errors. Key Features: • Multiple Shape Sizing Options: Supports sizing for rectangular, round, and flat oval ducts, offering flexibility for various duct designs. • Customizable Dimensions: For rectangular and oval ducts, users can lock in one dimension, and the app calculates the other, ensuring precise results based on CFM, pressure drop due to friction, or velocity. • Duct Location Intelligence: offers the user predefined parameters to use as starting point and reference when selecting duct sizes so users at HVAC experience level can make confident selections. Why Choose Digiduct? Unlike other duct sizing tools, Digiduct goes above and beyond. It doesn’t just provide basic size outputs—it evaluates the location and context of your duct (high-pressure vs. low-pressure, shaft vs. plenum), alerting you if your selection exceeds maximum pressure drop or velocity limits. This added layer of intelligence ensures higher accuracy and gives users confidence that their sizing is optimal for the application. Get the assurance of precision with Digiduct—designed to meet the demands of real-world HVAC scenarios.

HVAC Duct Sizing Calculator is the professional duct sizing tool for HVAC technicians, engineers, and contractors. Calculate correct ductwork dimensions based on airflow (CFM), velocity, or friction rate using ASHRAE standard sizes and ACCA Manual D methodology - the industry standard for professional air conditioning system design. SIZING METHODS: CFM-Based Method - Enter airflow and get recommended standard duct sizes instantly Velocity-Based Method - Size ducts by target air velocity (FPM) for proper sizing Friction Rate Method - Default 0.08 in. w.g. per 100 ft or custom pressure drop values DUCT TYPE SUPPORT: Round Duct Sizing - Calculate diameter based on CFM and friction loss Rectangular Equivalent - Find standard rectangular dimensions for any round size Flex Duct Correction - Automatic 10% correction factor for flexible ductwork All Standard Sizes - Results snap to ASHRAE industry-standard dimensions ADVANCED CALCULATIONS: Velocity Check - Ensures airflow stays within safe limits (optimal 400-900 FPM) Pressure Drop Analysis - Darcy-Weisbach calculation per 100 ft of duct Reynolds Number - Full hydraulic analysis for precision engineering Friction Loss Display - See calculated friction for every result OPTIONAL PRO UPGRADE — $2.99 ONE-TIME IN-APP PURCHASE The following features require a separate one-time in-app purchase. They are not required to use the calculator: • Unlimited saved calculation history • PDF export of results • Dark theme • Ad-free experience WHY HVAC PROS USE THIS CALCULATOR: Faster ductwork design than manual slide rules and ACCA charts ASHRAE-compliant and Manual D-verified sizing ensures proper system performance Cross-check velocity and friction rate for perfectly balanced systems Prevents over/undersized ducts that reduce efficiency and increase noise Field calculations without internet connection needed on job sites PERFECT FOR: HVAC design engineers planning new installations HVAC technicians calculating duct replacement sizing HVAC field technicians verifying existing ductwork AC contractors preparing accurate job estimates HVAC students learning Manual D design methodology Residential and commercial HVAC system design Based on ACCA Manual D constant friction method and ASHRAE Handbook fundamentals. Part of HVACTools Suite - the complete HVAC technician app for field calculations, refrigeration tools, and air conditioning diagnostics.