Standards-compliant calculators for hvac technicians in NZ & Australia. Free, no signup required. Works on mobile.
Each calculator opens on its own page — bookmark the ones you use most.
Calculate heating and cooling loads. Recommends kW AC or heat pump size for any room or zone.
Size round and rectangular HVAC ducts. ASHRAE velocity limits, pressure drop per 100 m.
Factory charge and pipe run adjustment for R-32, R-410A and R-134a split systems.