Changes

This page covers the current readiness release under local development. It is not a claim that these changes are deployed to ductstatic.com.

SI units (2026-09-10)

• Unit system toggle: a header switch flips the whole tool between English (imperial) and SI (metric) — CFM/in/ft/in. w.g. against L/s, mm, m, Pa. Your choice is remembered between visits.
• Every surface converts together: the diagram labels, property panel, duct sizing, results tables, and the calculation report all switch to the active system.
• Length shown when you place a duct: the quick-entry flyout now labels its length field in the current unit system (ft or m).
• Conversions stay grounded: the engine keeps computing in SI internally and projects stay saved in imperial, so reopening a project in either system shows the same physical result.

Readiness release (2026-09-08)

The following changes are prepared for review in the local repository and are not yet deployed:

• Reliable calculations: editing the model now marks results out of date until you recalculate; printing recalculates the current model rather than exporting stale results.
• Complete project round trips: saved projects now include site conditions, safety factor, report metadata, and an engine version, so reopening reproduces the same inputs.
• Air properties: the initial density matches the displayed default conditions, and valid values such as 0°F are preserved instead of being replaced.
• Input validation: nonsensical inputs and out-of-model conditions are explicitly rejected or flagged rather than silently coerced.
• Calculation report: a dedicated, versioned report with project metadata, assumptions, and a clear pressure basis replaced the print-the-page export.
• Example project: a one-click example lets you inspect a completed calculation before building your own.
• First use: a mobile-friendly intro defers full modeling to desktop; the visit counter and prominent donation were removed.

Before this release (deployed)

Later release history will be listed here as deployments land. For now, treat DuctStatic as an estimation tool for review, and verify results with a qualified engineer.