Describes the results of an evaluation of the accuracy of three solar models in general use - MAC, CCF and CMM. Four widely separated sites in Canada were selected for the study. The models were used to produce both total solar radiation and diffuse solar radiation on a horizontal surface and the calculated values were then compared with the measured or recorded values. Finds the MAC model had the smallest errors. The results for diffuse insolation were poor for all the models.

KEYWORDS: Calculating, measuring, comparing, accuracy, Canada, solar radiation, insolation