What it does
Cool Calc is a web-based HVAC design suite for Manual J loads, Manual S equipment selection and Manual D duct work.
Cool Calc connects Manual J loads to Manual S equipment selection and Manual D ducts. Geometry can come from LiDAR, a floor plan, satellite tracing or free drawing. An account lets users build/explore a project before payment; Manual J results require a per-project purchase or subscription. The per-project offer includes J/S/D and Scan, while Pro offers unlimited projects; Pro+ automation/API features are still presented with a waitlist. Browser work needs internet, but the documented LiDAR scan can be captured offline on supported iPhone Pro/iPad Pro hardware and opened later on other devices. Projects can be shared inside or outside an organization. The terms put responsibility for retaining customer records on the user and reserve commercial API licensing for outputs incorporated in a paid solution.
Strengths
- Connected load, equipment and duct workflows
- Several geometry-entry methods
Watch out for
- Viewing completed results requires payment under the described workflow
Best for
- Preparing a residential HVAC design calculation
Sources
- Cool Calc - Web-based Manual J,S, and D Design Software (Oct 26, 2026)
- Cool Calc Plans, Devices and Sharing (Oct 26, 2026)
- Cool Calc Terms of Use, Updated2025 (Oct 26, 2026)