The introduction of daylight through window systems to building interiors has the potential to save electric lighting energy and heating and cooling loads. Therefore, combined lighting and building thermal energy simulations based on hourly local weather data must be performed to estimate accurate total building energy use. This paper develops a fast and accurate annual daylight simulation approach for spaces with daylight systems and exterior obstructions can be performed. To compute the illuminance contribution from the sky and the sun, a daylight coefficient approach were studied. The proposed annual daylight simulation method consumes much less computation times required for the sun and sky annual daylight simulations, respectively, using the standard RADIANCE rtrace method.