HVAC Engineering Calculators Directory
Deterministic, peer-reviewed computational engines for building science, fluid dynamics, heat loss, and refrigerant diagnostics. 100% client-side precision with zero database tracking.
All 21 Engineering Tools
Filter by domain or search for specific parameters (CFM, BTU, sensible heat, static pressure, A2L glide):
Digital Ductulator & Air Duct Sizing Tool
Free online ductulator for HVAC engineers. Size round, rectangular & oval ducts via equal friction (Colebrook-White). Real-time 2D visualizer.
Flexible Duct CFM & Friction Drop Chart
Interactive flexible duct CFM chart for 4" to 20" round ducts. Compare airflow across 0.05 to 0.15 in. wg friction rates with sag and compression derating.
HVAC CFM & Airflow Calculator
Calculate HVAC airflow (CFM) from duct size, air velocity (FPM), sensible heat load (1.08 × ΔT), or room ACH. Free client-side precision.
Kitchen Range Hood CFM & Make-Up Air Sizer
Calculate required kitchen range hood CFM for gas and electric cooktops. Check mandatory IRC Section M1503.6 make-up air code requirements.
Duct Friction Loss & Total Equivalent Length (TEL) Sizer
Calculate ACCA Manual D Total Equivalent Length (TEL), Available Static Pressure (ASP), and Design Friction Rate (FR) for residential HVAC duct design.
MERV Air Filter Sizing & Static Pressure Drop Sizer
Calculate HVAC air filter face velocity (FPM) and static pressure drops across 1-inch, 2-inch, and 4-inch deep MERV 8 to MERV 16 pleated media.
BTU Heating & Cooling Load Calculator
Estimate whole-home and room heating and cooling loads (BTU/hr and Tons) based on square footage, climate zone, insulation quality, and window exposure.
AC Tonnage & Room Capacity Calculator
Match room and home square footage to required air conditioning tonnage (1.5 to 5.0 Tons) with regional climate adjustments and SEER2 operating cost modeling.
HVAC Model Number Tonnage Decoder
Decode Carrier, Trane, Lennox, Goodman, Rheem, Daikin & ICP model numbers. Instant nominal tonnage, SEER rating, manufacture year, and CFM airflow.
Mini-Split Multi-Zone Sizing Calculator
Size multi-zone ductless mini-split systems. Match room heat loads to indoor wall/cassette heads (6k to 24k BTU) and outdoor multi-port condensers.
Target Superheat & Subcooling Charging Calculator
Calculate target superheat (fixed orifice) and target subcooling (TXV) across R-454B, R-32, R-410A, and R-22 with EPA fault isolation guidance.
Digital Refrigerant Pressure-Temperature Chart
Interactive digital Pressure-Temperature chart for R-454B, R-32, R-410A, R-22 and 30+ refrigerants. Instant bubble and dew point saturation curves for 2026 A2L.
Psychrometric Chart & Moist Air Calculator
Calculate moist air thermodynamic properties from any 2 inputs (Dry Bulb, Wet Bulb, Dew Point, RH, Enthalpy) with altitude barometric compensation.
Refrigerant Line Set Charge & Weigh-In Calculator
Estimate the manufacturer-specified initial refrigerant weigh-in adjustment for R-454B, R-32, and R-410A line sets using sourced OEM profiles.
Heat Pump Sizing & Balance Point Tool
Calculate heat pump thermal balance point, cold-climate low-ambient heating capacity (47°F, 17°F, -5°F), and auxiliary electric backup heat strip sizing.
Furnace Sizing & AFUE Efficiency Calculator
Calculate required furnace input and output BTU based on home square footage, climate zone, and AFUE efficiency (80% vs 96% condensing).
Hydronic Boiler & Baseboard Sizing Calculator
Size residential hydronic heating boilers based on fin-tube baseboard linear footage, cast-iron radiator EDR, and indirect domestic hot water priority.
Garage & Workshop Heater Sizing Calculator
Size gas unit heaters, forced-air electric heaters, and radiant tubes for 1 to 3-car garages. ACCA Manual J & ASHRAE heat loss with slab insulation derating.
Combustion Air & Confined Space Sizer (NFPA 54 / IFGC)
Size mechanical room combustion air openings per NFPA 54 and IFGC. Instant 50 cu ft/1,000 BTU confined space test and indoor/outdoor louver duct sizing.
Insulation R-Value & U-Factor Calculator
Build multi-layer wall, roof, and floor assemblies to calculate total R-value (R-total) and overall U-factor with IECC 2021/2024 climate zone compliance checks.
Building Heat Loss & Infiltration Calculator
Calculate whole-building peak heat loss combining envelope conductive transmission (U * A * Delta T) and blower door air infiltration leakage.
Governing Standards & Physics
Built on First Principles & Industry Standards
Every tool in this directory executes strictly verified formulas from major engineering authorities:
Airflow & Hydraulics
Governed by Colebrook-White friction factors, Darcy-Weisbach head loss, SMACNA duct leakage classes, and ACCA Manual D sizing protocols.
Read Airflow Pillar Guide →Cooling & Thermal Loads
Standardized on ACCA Manual J (8th Edition), Manual S equipment selection criteria, and AHRI 210/240 performance ratings.
Read Cooling Pillar Guide →Heating & Electrification
Inverter heat pump thermal balance point models, cold-climate COP deratings, NFPA 54 combustion air sizing, and Hydronics Institute baseboard EDR specs.
Read Heating Pillar Guide →Diagnostics & Refrigerants
NIST REFPROP saturation curves, zeotropic A2L temperature glide evaluation (R-454B, R-32), and target subcooling/superheat charging charts.
Read Diagnostics Pillar Guide →The 100% Client-Side Privacy Guarantee
Unlike traditional subscription software, all 21 HVACLogic calculators evaluate formulas directly in your browser. Project numbers, room dimensions, equipment bids, and client data never leave your device. Zero tracking, zero database storage, and instant offline PWA calculation speed.