From room loads to a quoted machine — one tool.

You design or specify HVAC for real buildings. HVAC Builder takes you from envelope and internal loads to per-room comfort and per-system energy — solved with real thermodynamics against a real weather year — and then puts suppliers' actual machines next to your numbers, one quote request away.

Open the builder — free

No credit card. 25 free point solves every month, more on any paid tier.

Buildings tab: rooms and machines as blocks — click a machine's port, then a room, to assign it

Whole-building simulation

Draw rooms as blocks — area, envelope UA, day/night gains, solar aperture, setpoints. Assign each to a machine and run the year: unmet hours, temperature histograms, and energy per room and per system. Recirculating units breathe their rooms' actual return air.

Machines you can trust — or open up

Use suppliers' ready-made systems as sealed blocks, or build your own from compressors with AHRI 540 maps, real coil geometry, and evaporative media. Same solver either way — no brochure numbers.

Order from the numbers

Component selections and duty-matched supplier systems carry one-click quote requests. Your RFQ arrives at the vendor with the design attached — sizing conversations start half-finished.

A workflow that matches how projects actually run

DesignAssemble the air-handling system in 3D — or start from a supplier preset or the AI assistant.

VerifySolve the design point; check states, duties, COP on the psychrometric chart.

Scale upModel the building: rooms, gains, setpoints; assign one or several machines per room.

SimulateRun a real typical meteorological year (50 cities, PVGIS) with load-following control.

DeliverPrint-styled reports — spec report per system, building report with room comfort and system energy. PDF or HTML.

Building run results: per-machine load-duration curves and peak-day profiles showing sizing margin against delivered capacity

Defensible numbers

Every result comes from published physics — ASHRAE psychrometrics, IAPWS-IF97 water properties, AHRI 540 compressor maps, CoolProp refrigerant data, EnergyPlus-published correlations — and the solver reports its convergence instead of handing you a silent partial result. Estimates, clearly labeled as estimates, that you can defend in a design review. Every source, linked →

Find a machine that fits your building

Suppliers publish complete machines here — each with its own public page, its manufacturer's data, and performance solved by the engine you design with. Filter by capacity and market, open one in the builder, drop it into your building model, and see how it behaves in your climate before you ask anyone for a price.

Browse published systems Browse components

The public systems directory: supplier machines filtered by capacity band, market and supplier, with counts on every filter