Solar Photovoltaic Panels are considered as one of the most powerful alternative renewable and sustainable energy sources. However, a major challenge is the effect of dust accumulation on the photovoltaic panels in natural outdoor environment as it reduces the transmissivity of the light on the surface of the solar panels. For many small communities, the decision of implementing mono or polycrystalline PVs should consider economic aspects. This study is a case study that is held at The British University in Egypt at El Sherouk city to study the effect of different parameters such as dust accumulation, water cooling and coating on the performance of both mono- and poly-crystalline panels at El-Sherouk City. The effects of high temperature and dust accumulation on different solar panels placed in natural outdoor conditions at El- Sherouk City are studied and the electrical performance of the solar panels is represented by measuring several characteristic parameters of dusty and cooled PV panels compared to cleaned and non-cooled panels. The effect of the tilt angle on the accumulation of dust on the surface of the solar panels is, also, studied. The mono-crystalline solar panels are installed at tilt angles 0°, 15°, 30°, 45°, and 60° for one month without cleaning, by any method. The results shows that the power reduction percentage is 17%,20%,25%,27% and 30% for tilt angles 60°,45°,30°,15° and 0°; respectively. Tilt angles 15° and 30° show to be optimal for the installation of the PV solar system, as they produce the highest amount of output power. It is found from the study that the accumulation of dust on the surface of different types of solar panels can reduce the efficiency by 30%. While the high temperature can reduce the efficiency by up to 10 %.