Ductulator: Duct & CFM Calc

HVAC Master Calc is a free ductulator, superheat & subcooling calculator, refrigerant PT chart, and BTU load estimator — all in one HVAC calculator app built for technicians, installers, and contractors. Size ducts by CFM, check refrigerant charge, and estimate loads right from your pocket. Fully offline, no subscription, no ductulator wheel needed.

Whether you're sizing ductwork on a new installation, checking superheat during a service call, or estimating BTU loads for a room, this app is built to handle the rigors of field work.

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🛠️ CORE FEATURES
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📐 Ductulator — CFM & Duct Sizing Calculator
- Calculate required CFM (Cubic Feet per Minute) based on room parameters.
- Determine optimal dimensions for round and rectangular ductwork — a digital duct sizer that replaces your old ductulator wheel.
- Supports standard and custom duct sizes for residential and commercial systems.

🌡️ Refrigerant PT (Pressure-Temperature) Charts
- Quick-lookup PT charts for common refrigerants (R-410A, R-22, R-134a, R-404A, R-407C, and more).
- Instantly find saturation pressure for any given temperature.
- Essential for charging, diagnosing, and servicing AC and refrigeration systems.

❄️ Superheat & Subcooling Calculators
- Calculate target superheat for systems with TXVs or fixed orifice devices.
- Calculate subcooling to verify precise refrigerant charging.
- Built-in ranges help you assess system performance immediately in the field.

🏠 BTU Load Estimator
- Estimate heating and cooling BTU requirements for individual rooms.
- Input dimensions, insulation levels, and climate zones for quick air conditioner and heat pump sizing.
- Ideal for preliminary equipment sizing and load verification.

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⚡ BUILT FOR THE FIELD
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✅ Offline Ready — No internet connection required. Use it in basements, rooftops, or remote sites.
✅ Tech-Focused Design — Clean, high-contrast interface designed for easy reading in bright sunlight.
✅ Time-Saving Utilities — Get results in seconds instead of running manual formulas.
✅ Lightweight — Small file size that doesn't drain your battery or waste storage.

WHO USES IT

• HVAC technicians — duct sizing, PT lookups, and charge checks on service calls
• HVAC installers — verify duct runs and equipment sizing before installation
• Contractors & estimators — fast BTU and airflow numbers while quoting
• Apprentices & HVAC students — learn duct sizing, superheat, and subcooling hands-on

Whether you call it a ductulator, duct sizer, air duct calculator, superheat calculator, or PT chart app — HVAC Master Calc gives you the numbers in seconds.

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⚠️ PROFESSIONAL USE DISCLAIMER
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This application is a field reference and estimation tool intended for use by trained HVAC technicians. It does not replace formal engineering calculations, Manual J load reports, or manufacturer-specific data. Results are estimates based on standard HVAC formulas and should be verified by a qualified professional before making installation or design decisions. This app is not affiliated with ASHRAE, AHRI, or any government body. Always follow local building codes and safety regulations.