Also see CONScalcs, a suite of five construction calculators that includes HVACcalcC for only $59.95. If purchased separately, would cost $112.00. HVACcalcC is a powerful yet easy to use graphical simulation of a hardware calculator with features specifically designed for users involved in HVAC design and contracting work.It features built-in formulas for calculating eqivalent duct diameters, relative humidity, fuel consumption, and infiltration and friction loss.HVACcalcC can be used as a standard decimal calculator with square root and 9 memories for general problem solving. In addition, data is provided on thermal properties of various building materials. The user can also toggle between Metric and Imperial units modes.