About AnyHVAC

Practical HVAC tools. Free and easy to use.

AnyHVAC started with a simple idea: everyday HVAC calculations shouldn't require jumping between multiple websites, spreadsheets, reference books, and disconnected tools.

Our Mission

Build practical HVAC calculators, references, and resources that are easy to use, transparent in how they work, and available without a paywall.

Our Approach

Practical

Built around common HVAC design, field, and engineering workflows.

Transparent

Calculations and assumptions should be understandable, not hidden behind a black box.

Accessible

Core AnyHVAC tools are intended to remain free and easy to access.

Independent

Support, sponsorships, affiliate relationships, and advertising do not affect calculation results or engineering outcomes. Paid relationships will never change a result or determine the best engineering choice.

Project background

AnyHVAC is a project by Idea House, focused on practical HVAC design relationships: airflow, duct geometry, pressure loss, moist-air properties and air mixing. Calculators are paired with explanations, worked examples and references so users can understand the inputs and interpret the results in a project context.

The site provides calculation and reference assistance, not project-specific professional engineering services. Use the methods alongside applicable specifications, codes, manufacturer data and professional judgment. Read the Engineering Disclaimer for the full scope and limitations.

Calculation methods and references

The method depends on the question being answered. References support understanding of the approach; they do not constitute an endorsement, certification or independent review of AnyHVAC.

Duct sizing uses an equal-friction approach with round and rectangular comparisons. The Duct Design Quick Reference explains sizing relationships and project checks, with ASHRAE Handbook—Fundamentals, Duct Design as a technical reference.
Psychrometric properties are calculated with the MIT-licensed PsychroLib backend, with explicit unit, moisture-input and atmospheric-pressure handling.
Mixed-air analysis converts incoming airflow to dry-air mass flow using specific volume, then balances humidity ratio and enthalpy at a common pressure. It uses the same psychrometric property engine and reports a warning when the single-phase mixing model reaches saturation.

Support AnyHVAC

AnyHVAC is free to use. If the tools save you time, you can optionally support future development.