A software tool that aids engineers in climate control selection, Therm v3.0 can be used with Windows 95/97 to quickly and efficiently calculate an enclosure's convective heat loss, cooling requirements and potential climate control solutions. Users enter the ambient temperature, desired internal temperature, available voltage/frequency, size or part number of firm's enclosure being used or dimensions of other maker's enclosure, location of enclosure, and heat loss from the internal electronics. Therm v3.0 can calculate an estimated heat loss via measured enclosure temperature rise without knowing the actual component heat dissipation. Users can create their own heat loss database, based on their most frequently used components. Upon completing the calculation, Therm v3.0 specifies which of firm's filter fan, heat exchanger, air conditioner, air/water heat exchanger, or heater to be used for the application. Therm comes on CD-ROM or two 3.5" diskettes.