CL4M Commercial Cooling and Heating Loads

Uses ASHRAE methods and algorithms to calculate cooling loads, heating loads and air requirements for each space, and coil specifications, for commercial buildings. CLTD's, SHGF's, CLF's and almost all other factors in the ASHRAE load calculations for each surface and space are calculated and displayed for the engineer's inspection. Latitude and longitude of building location may be specified to the degree, altitude to the foot, and calculations are made for any range of days of the year, and range of hours desired. Building may be rotated or reflected and construction types easily changed for studies.
Handles variations in sky clarity, ground reflectivity, building shading, humidity and altitude. Almost unlimited flexibility in wall, roof and glass descriptions, load types and profiles, A/C set points, partial or full return air plenums in each zone. Worldwide application; weather tapes not required. Psychrometric calculations are altitude corrected.
Uses algorithmic calculations rather than disk database lookup for CLTD's, SHGF's, CLF's and psychrometric calculations, for greater speed and accuracy. This is a substantial difference from most similar programs.
Set up for large, multi-story buildings, but sufficiently convenient to be used for smaller buildings and residences. Program code is extensively optimized and fully compiled so at to be exceptionally fast. Critical portions are done at assembly language level for greatest speed.


cooling loads, heating loads, commercial buildings



Expertise Required

Familiarity with ASHRAE commercial load calculation theory and methods; HVAC design experience is desirable. Computer experience not necessary.


Over 500.


HVAC engineers and commercial HVAC contractors.


Overall design characteristics of the building such as wall, roof and glass specifications and dimensions for each zone. Internal load characteristics must be known. Trials may be run to compare results.


HVAC cooling, heating loads, air requirements for each zone and air handler, as well as coil specifications are output. Details of calculations for each surface in every zone may be displayed and studied; zone and air handler load details are printed out, together with building totals.

Computer Platform

PC-compatible, 286 or higher, running any flavor of Windows or DOS.

Programming Language

Fully compiled with portions in assembler language.


Uses ASHRAE methods, in most respects the same as those of National Bureau of Standards publication No. 69. Program runs in all DOS and Windows environments. In wide commercial use for over 10 years. Uses algorithmic calculations rather than table lookup. Believed to be fastest program in commercial use on microcomputers. Free technical assistance by telephone, fax or email.


This is a DOS program, which installs and runs itself through any version of Windows by clicking its Windows icon.



MC2 Engineering Software


2451 Brickell Avenue 15L
Miami, Florida 33129
United States


(305) 860-8044


(305) 860-9146




Site license for most powerful 255-zone version - $995.00, 40-zone version $450.00 - enough capacity for most commercial buildings. Lifetime technical service at no charge by telephone, email or fax. Upgrades from time to time at $75 to $125.