Version 3.1 Full SI (metric) unit support — switch the entire app between Imperial and SI units from one toggle in the Guide tab. • All 4 Lab simulators (AHU, Refrigeration Cycle, Psychrometric Chart, Chiller Plant) now display °C, kPa, kJ/kg, kW, and g/kg when SI is selected • All 8 Engineering Calculators (loads, duct sizing, pump head, superheat/subcooling, cost of operation, SHR) convert inputs and results to metric • Refrigerant reference data (critical temp/pressure, saturation ranges) switches units too • Your preference is saved automatically

Version 3.0 — HVAC Calculators + Refrigerants Database This release adds two major HVAC-specific features that make this app a genuinely useful daily tool for working engineers and technicians: NEW — HVAC CALCULATORS TAB Eight engineering calculators every HVAC designer runs constantly: - Sensible heat load (q = 1.08 × CFM × ΔT) - Latent heat load (q = 4840 × CFM × ΔW) - Mixed air temperature blender - Duct sizing (equal-friction method) - Pump friction head loss - Refrigerant superheat / subcooling diagnostic with charge interpretation - Annual cost of operation - Sensible Heat Ratio classifier Every input is a slider — results update live. NEW — REFRIGERANTS TAB Side-by-side database of 9 common refrigerants (R-22, R-410A, R-134a, R-32, R-454B, R-1234yf, R-290, R-744, R-717) with ASHRAE 34 safety class, GWP, ODP, critical properties, operating pressure ranges, applications, and engineering notes. Filter by family. NEW — WHAT'S NEW SCREEN Auto-presented on first launch with a guided tour of the v3.0 features. NEW — HOME SCREEN The home tab now prominently features the new Calculators and Refrigerants sections so they're visible the moment you open the app. EVERYTHING ELSE All v2.0 features carry forward: the four animated simulators in the Lab, the curriculum, the design projects, the searchable reference, and all 56 illustrations. Your saved progress migrates automatically. Thanks for using HVAC Visual Learning Studio. Tap the feedback link in the Guide tab to send suggestions.

Version 2.0 — Major Visual Refresh This release nearly doubles the illustrated reference gallery and reorganizes it into a clearer narrative flow. WHAT'S NEW - 56 illustrated diagrams (up from 35) — every category expanded with photo-realistic and engineering-grade visuals - 11 organized galleries (up from 7) — including new Whole-House Residential, Indoor Mechanical Room, Single-Family Block Diagrams, and AHU/VAV & Zoning categories - Full-screen viewer with pinch-to-zoom, double-tap reset, and swipe-between-images - Refined narrative ordering — fundamentals → whole-house → multi-unit → commercial → industrial → ventilation → controls → documentation - "HVAC Simulation Lab" — refined title and navigation in the Lab tab THE LAB STAYS LIVE All four animated simulators are unchanged and ready to use: - AHU Simulator — airflow particles, spinning fan, modulating dampers, virtual zone thermostat - Refrigeration Cycle on a P-h diagram with live COP and EER - Psychrometric Chart with live state plotting and process lines - Chiller Plant with staging logic, cooling tower, and animated water flow CURRICULUM, PROJECTS, REFERENCE All curriculum modules, design projects, and reference content from v1.0 carry forward unchanged. Your progress, bookmarks, and last-viewed lesson all migrate automatically. Thanks for using HVAC Visual Learning Studio. If you find this update useful, please leave a review — and tap the in-app feedback link to send us your suggestions. We read every one.