SOLAR-5 logo.

Displays 3-D plots of hourly energy performance for the whole building or for 9 schemes and any of 40 different components. SOLAR-5 also plots heat flow into/out of thermal mass, and indoor air temperature, daylighting, output of the HVAC system, cost of electricity and heating fuel, and the corresponding amount of air pollution. It uses hour-by-hour weather data. It contains an expert system to design an initial base case building for any climate and any building type, that an architect can copy and redesign. Contains a variety of decision-making aids, including combination and comparison options, color overlays, and bar charts that show for any hour exactly where the energy flows.


design, residential and small commercial buildings


SOLAR-5 has been validated against DOE-2 and BLAST using the BESTEST procedure.

Expertise Required

Intended to be self-instructional, with built-in help options; requires only basic familiarity with computers and with architectural vocabulary.


Estimated in the thousands; known to run in over a third of the schools of architecture in the U.S. and in dozens of architectural firms.


Architects, students of architecture, building managers, knowledgeable homeowners.


From only four pieces of data initially required (floor area, number of stories, location, and building type), the expert system designs a basic building, filling in hundreds of items of data; user can make subsequent revisions, usually beginning with overall building dimensions, window sizes, etc.


Dozens of different kinds of 3-D plots, tables, and reports. For example, displays heat gain/loss for over a dozen different building components; shows heat flow into and out of the thermal mass of the building, as well as the output of the heating and air conditioning systems; displays air temperatures (outdoors or indoors) and air change rates; predicts the cost of heating fuel and electricity; calculates the building's air pollution 'footprint' for six gasses including carbon dioxide; (the above output plot of heat gain shows why South Windows are such good winter passive solar collectors).

Computer Platform

All Windows platforms and emulators; needs 2 megabytes of RAM

Programming Language

Visual Fortran


Intended for use at the very earliest stages of the design process (when most of the decisions that determine a building's energy performance are made); extremely user friendly; extremely rapid, calculating all 8760 hours of the year using TMY data in condensed format (see our web sites for data sources and conversion routines).


Not intended for complex mechanical system design or equipment sizing.



Department of Architecture and Urban Design


Box 951467
University of California at Los Angeles
Los Angeles, California 90095-1467
United States


+1 (310) 825-7370


+1 (310) 825-8959




SOLAR-5 has now been incorporated in HEED, Home Energy Efficient Design, a newer and more user-friendly version. SOLAR-5 was mostly recently updated in June 2000 and is free. HEED and SOLAR-5 can be downloaded from the web site.