This HVAC system type recommender helps narrow the field of system options for a project. Answer a handful of questions — building type, size, climate zone, zone count and control needs, design priority, and central-plant availability — and the tool ranks candidate systems such as VAV, fan coils with DOAS, VRF, PTAC/PTHP, packaged rooftop units, central chiller plant, and heat pumps, showing the top three with pros and cons.
It is a discussion starter, not a final design. The ranking reflects common engineering judgment about where each system fits best; the right choice for a given project still depends on detailed load, energy, and cost analysis.
Formula & Method
Score = building-type match + size match + climate match
+ zone-control fit + priority fit + plant-availability fit
Rank systems by total score → show top 3
Each candidate system carries tags for the building types, sizes, and climates it suits. The tool adds weighted points for every match — more for a building-type fit, fewer for secondary factors — then sorts by total. There is no single governing equation; this is a rule-based selection method, the kind of decision matrix used in ASHRAE system-selection guidance, made transparent so you can see why a system ranked where it did.
Frequently Asked Questions
How does the system type recommender work?
It is a rule-based scoring tool. You answer questions about building type, size, climate, zone count, priority, and whether a central plant is available, and each candidate system earns points where it matches your project. The systems are then ranked, and the top three are shown with their pros, cons, and a best-match label. It is a starting point for discussion, not a final design decision.
When should I choose VAV versus VRF?
VAV with a central air handler is strong for larger multi-zone commercial buildings where good part-load efficiency, dedicated outside-air control, and economical zoning matter. VRF suits projects that need individual room control without a central air handler and excellent part-load efficiency, but it has refrigerant piping length limits and usually needs a dedicated outdoor air system for ventilation.
Does climate change the recommendation?
Yes. Climate affects both load profile and equipment suitability. Air-source heat pumps lose capacity in very cold climates, hot and humid climates push toward systems with strong dehumidification and dedicated outside-air handling, and mild marine climates open up simpler low-cost options. The tool weights each system's fit to the selected climate zone.
Is this a substitute for a full HVAC design?
No. The recommender narrows the field quickly, but final system selection requires load calculations, a life-cycle cost analysis, ventilation design per ASHRAE 62.1, energy code compliance per ASHRAE 90.1, and coordination with architecture and structure. Use the result to frame options, then validate the chosen system with detailed engineering.
This calculator handles one step. AIM Works runs the complete MEP design workflow — thermal load calculations, duct & pipe networks, equipment selection, code compliance, and an AI design assistant — in one tool.