PsyCalc® uses industry standard
calculations to determine psychrometric property values.
Each time a change is made to the input values PsyCalc®
recalculates psychrometric properties. The program uses
calculation methods and equations that have been
generally accepted by the HVAC industry and ASHRAE.
The limits set within the
program are imposed due to inaccuracies in the
calculation methods and/or practical limits of the
technology and industry for which PsyCalc® was created.
The current limits are:
Dry Bulb Temperature -60 to 1500ºF
(-51 to 815.5ºC)
Dew Point Temperature -80 to 200ºF
(-51 to 71.1ºC)
Altitude -500 to 65,000 Ft (-152
to 19,800 m) above sea level
Pressure .7 to 400 psia (5 to
(Moisture content is directly
limited by the dew point limit.)
There is no simple way to
state the accuracy of the calculated values presented by
PsyCalc® over the entire range of its operation. Suffice
it to say that standard industry recognized equations
have been used and every effort made to avoid errors due
It is the users responsibility however to qualify the accuracy and its applicability to the work they do.
PsyCalc® was written for use by the HVAC industry and it is the authors opinion that it provides adequate accuracy
for this industry. Please review the Disclaimer for further