This paper aims to review the achievements of previous studies addressing the capability of atriums for providing adequate levels of daylight and visual comfort. This study also performs several simulations using Radiance IES-VE software predominantly with the target to support the literature review results. The analysis discusses ways of daylight transmission through different atrium structures.

In European countries, buildings are the major energy consumers due to the general low energy performance of the existing building stock. To achieve the ambitioned targets for emissions reduction, it will be necessary to take actions for its large scale renovation. However, today's standards are mainly focused on new buildings, guiding the improvement of the energy performance of the existing buildings into expensive processes and complex procedures that seldom are accepted by users, owners or promoters.

A new analysis framework is developed and applied to assess the benefits of building energy efficiency policies and programs. One of the main advantages of the new energy productivity analysis is that it accounts for both economic and energy performances of energy efficiency actions using only one metric. Specifically, the approach applies the concept of energy productivity to the building sector and accounts for both value added and energy savings of energy efficiency measures.

The German government has developed a variety of policy instruments intended to reduce national CO2 emissions. These instruments include a programme administered by KfW bank, which aims at improving the energy efficiency of buildings. It provides attractive credit conditions or subsidies to finance refurbishment measures which improve the energy efficiency of buildings significantly. The refurbishment programme leads to a reduction in energy use, which benefits private investors by reducing their energy bills.