HVACalc

HVAC Design & Diagnostics

Only for iPhone

$0.99 · In‑App Purchases · Designed for iPhone. Not verified for macOS.

iPhone

New in 1.2: Manual J-lite per-surface loads, selectable duct aspect ratios, and reference-tested formulas — from rule-of-thumb to defensible in seconds. HVAC Calculators puts a field-ready reference in your pocket. Browse 40 purpose-built tools for system design, airflow, refrigeration, diagnostics, and economics so you can check loads, balance air, and verify performance before you leave the rooftop. **What you can do** Size comfort systems with BTU Load, AC/Furnace/Boiler/Heat Pump, ventilation load, make-up air, humidity control, and expansion valve calculators, plus an optional Manual J-lite per-surface envelope mode for defensible heating and cooling loads. Dial in airflow with Duct Sizing (round or rectangular, 1:1 through 4:1 aspect ratios), CFM vs ACH, friction loss, fan law, grille/diffuser sizing, and static pressure tools. Keep refrigeration and hydronics on point with refrigerant charge, line sizing, coil performance, pump head, water/gas pipe sizing, and glycol concentration helpers. Troubleshoot faster using superheat & subcooling, temp rise/drop, dew point, wet bulb, relative humidity, moist air enthalpy, compressor efficiency, and an ASHRAE 62.1 ventilation workflow. Run the numbers behind the job with unit conversions, wire size and Ohm’s Law, motor amperage, energy cost estimates, efficiency payback, ROI, and life-cycle cost comparisons. **Built for the field** Real-time answers update as you type, with optional formula callouts when you need to explain the math. Smart search plus categorized sections so you can jump straight to the right calculator. On-device calculations mean you can keep working even when the mechanical room has no signal. Unit preferences (°F/°C, in. w.c./Pa/kPa) persist across sessions so every calculator opens the way you expect. Help and abbreviation references keep apprentices productive and remind veterans of rarely used constants. Light and dark mode support for easy reading in any environment. Core calculators are free forever. An optional one-time Pro upgrade unlocks the full suite of 40 tools. Whether you’re sizing a replacement rooftop, double-checking duct velocities, or building a payback story for an upgrade, HVAC Calculators gets you from rule-of-thumb to defensible numbers in seconds. Disclaimer: These tools provide quick estimates for educational and planning purposes. Always confirm final selections with manufacturer data, engineering references, and all applicable codes and standards before installation.

Ratings & Reviews

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Version 1.2 — Accuracy upgrade • Manual J-lite mode in BTU Load. Per-surface envelope calculation with walls, ceiling, floor, glazing (U-factor + SHGC), infiltration via ACH50, and internal gains. Loads scale to ASHRAE design temperatures for the selected climate zone. Quick Estimate stays available for ballpark sizing. • Duct sizing aspect ratios. Rectangular ducts now pick from 1:1, 1.5:1, 2:1, 3:1, and 4:1 — the calculator returns both dimensions. • Area-based window loads. Glazing in Quick Estimate now scales by area × U·ΔT plus SHGC solar gain instead of per-window constants. • Climate-aware design temps. Every climate zone exposes 99% winter, 1% summer, and coincident humidity ratios from ASHRAE Fundamentals. • Tightened formulas, twenty new reference-case tests locking psychrometric and load math to published ASHRAE values.

Version 1.2.0

The developer, Bob Sanford, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Linked to You

    The following data may be collected but it is not linked to your identity:

    • Identifiers
    • Usage Data

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Accessibility

The developer has not yet indicated which accessibility features this app supports. Learn More

Information

Seller
  • Bob Sanford
Size
  • 9.8 MB
Category
  • Reference
Compatibility
Requires iOS 16.6 or later.
  • iPhone
    Requires iOS 16.6 or later.
  • Mac
    Requires macOS 13.5 or later and a Mac with Apple M1 chip or later.
Languages
  • English
Age Rating
4+
In-App Purchases
Yes
Copyright
  • © @ 2025 Bob Sanford
  • Developer Website
  • Privacy Policy

    • More by Bob Sanford

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