Cooling and heating load calculations for air-conditioned and heated buildings have been calculated for three different cities in Jordan, representing three climatic regions; namely, Irbid, Amman and Aqaba. To analyze the insulation effect of buildings, for each region four combinations of wall and ceiling insulation were considered: no insulation; only wall insulated; only ceiling insulated; and both ceiling and wall insulated. The results showed that the average monthly heating load was reduced when only walls were insulated; however, this has a negative impact on the average monthly cooling load. In the case where only the ceiling was insulated, both the monthly cooling and heating loads were reduced. A comparison showed that with both wall and ceiling insulated, the energy requirements could be reduced by more than 40%. In Aqaba, with both walls and ceiling insulated, there would be no need for any heating during the whole year and in both Amman and Irbid there were at least four months in which there would be no need for either heating or cooling.