Best software for hvac design

If you mean professional HVAC engineering/design software, there isn't one universal winner—but for most commercial HVAC work, I'd put Carrier HAP and Trane TRACE 3D Plus at the top.

My picks

🥇 If I had to choose one: Carrier HAP

HAP is particularly strong because it goes beyond simply calculating heating and cooling loads. It can size HVAC systems and components, model energy use, and handle systems such as RTUs, VRF, VAV, central AHUs, chilled/hot-water systems, heat pumps, etc. It uses the ASHRAE Heat Balance method for load calculations. www.carrier.com

Carrier's current HAP v6 also incorporates EnergyPlus capabilities and graphical 3D building modeling, which makes it considerably more capable than the older versions of HAP. www.carrier.com

🥈 TRACE 3D Plus

I'd choose TRACE 3D Plus if you're doing sophisticated commercial engineering, particularly when energy modeling, system alternatives, central plants, and economic comparisons are important.

TRACE 3D Plus uses the DOE EnergyPlus engine and can take a project from building model → load calculation → HVAC system modeling → energy/economic analysis. trace3dplus.help.trane.com

Important distinction

If by "HVAC design" you mean actually drawing the ductwork, piping, equipment and construction plans, then neither HAP nor TRACE is the whole solution.

A typical professional workflow is more like:

Revit / AutoCAD → architectural & HVAC drawings HAP / TRACE → loads, equipment sizing, energy analysis Duct/piping software → detailed distribution sizing Manufacturer selection software → final equipment selection

If you're doing residential HVAC, the answer changes substantially—Wrightsoft Right-Suite or Elite RHVAC may be much better than HAP/TRACE because of Manual J, Manual S and Manual D workflows.

If you tell me whether you're designing residential, light commercial, or large commercial/industrial HVAC, and whether you need load calculations, duct design, equipment selection, or full construction drawings, I can narrow it down to the best 2–3 programs for your specific work.