Energy savings through enhanced daylight utilisation in residential buildings

The project aims to investigate whether there is a connection between the size of the windows in a home and the residents' use of the artificial lighting. Large windows allow more daylight in the home, and therefore it is reasonable to assume that the artificial lighting is used less in rooms or buildings with large windows. This has been the main hypothesis of the study.

The method of analysis was quite simple, as the residents reported when the first time in the afternoon (after 15:00) switched on the artificial lighting in the selected room types. The stated hypothesis can then be reformulated to express that in rooms with small windows it will be earlier dark, and therefore it is expected that the residents of these homes will turn on the light earlier than in the corresponding spaces with larger windows.

The results of the analyses show against expectations that cannot be found a significant correlation between the window size and use of electric lighting. Although there may be traced tendency for the expected correlation, the material is not sufficient to confirm this hypothesis. The trend suggests that there may be traced a difference of 15, perhaps 30 minutes, between the switch-on time in spaces (kitchens) with small windows in relation to the room with large windows. Although the hypothesis cannot be confirmed, it does not mean that there exist the expected correlation, but the material suggests therefore that the difference is quite limited, 15-30 minutes against an expected difference in the use of electric lighting by up to 60 minutes.