HVAC Ladder

New in 1.2: a guided tour that wires a real transformer circuit, a full Symbol Glossary, and instant dark mode. Draw clean ladder diagrams right from your pocket.

I'm a working HVAC tech, and I got tired of sketching ladder diagrams on the back of a napkin or trying to draw one on a whiteboard app that wasn't built for it. So I made this.

HVAC Ladder lets you draw clean control diagrams right on your phone — standing at the unit, in the truck, wherever you are. Tap a symbol from the library, drop it on a rung, label it, done. When you're finished you can export a PDF or PNG and send it to the office, a tradesman, or the customer.

What's in it:

• The symbols you actually use — contacts, coils, switches, thermostats, pressure and float switches, HOA selectors, transformers, overloads, fuses, and more • Single-phase and three-phase — add or drop the L3 leg, set your supply voltage, add a disconnect with fuse sizes • Thermostat and HOA terminal blocks that wire out to their own rungs • Notes you can drop anywhere on the drawing • Dark mode for working in a dim equipment room (your exports still print clean on white) • Example diagrams built in, so you can open one up and see how it's put together • Export a PDF or PNG, or save the file to pick back up later

No account, no subscription, no internet needed. It's just a tool that does the job.

Built by a tech, for the trade. If something's missing or you've got an idea, reach out — I'm listening.

Happy wiring.

Made with Godot.