In the market, the embodied energy payback time (EPBT) is the scale to measure and compare the viability of PV systems against other technologies. Although the impact of PV panels on the operational energy is significant, it is not considered at the time of EPBT estimation. Including savings in operational energy gained over the PV system life leads to shortening the total EPBT. This study shows that the ratio between PV outputs and savings in energy due to PV panels is about 1:3. For the southern and western PV facades of the UAE office buildings, the embodied energy payback time is 12-13 years. When reductions in operational energy are considered the payback time can be reduced to 3 years. It is obvious that the reduction in the operational energy due to the PV panels represents an important factor when the EPBT is estimated
