DuctCalc.ca – SaaS Engineering Tool with Stripe & iOS App

Founded and built DuctCalc.ca, a specialized SaaS application for HVAC mechanical engineers. This niche engineering tool enables professionals to calculate air duct sizing, velocity, and pressure drop on-the-go. Features a freemium model with Stripe subscription billing and a native iOS app.

Tech Stack

• Custom WordPress theme and plugin
• HTML5 Canvas for 2D duct visualization
• JavaScript algorithm for engineering calculations
• Stripe API integration for subscriptions
• Swift / iOS native app with in-app purchases
• PHP / MySQL backend

Challenge

HVAC engineers needed a quick, mobile-friendly tool to calculate duct sizing in the field. Existing solutions were desktop-only or overly complex. The solution needed accurate engineering calculations, visual representation, and a sustainable business model.

Solution

Designed and coded the engineering algorithm from scratch based on ASHRAE standards. Built an interactive HTML5 Canvas visualization showing duct shapes in real-time as parameters change. Implemented Stripe subscription billing with custom cancellation handling. Developed a native iOS app with in-app purchases, now published on the App Store. The freemium model offers basic calculations free with premium features available via monthly subscription.