Passive solar heating through glazing: The limits and potential for climate change mitigation in the European building stock

Abstract

Glazing transparency provides buildings with valuable solar energy during periods of colder weather, thus contributing to the mitigation of climate change. However, this same transparency also leads to heat loss which can offset heat gains. Although the use of insulated glazing addresses this challenge by multiplying the number of glass panes, at the same time it reduces the solar factor and thus the heating potential. This article aims to estimate the potential for passive solar heating in Europe according to the energy performance of glazing.This potential is undoubtedly a valuable resource for sustainable architecture. However, an analysis based on regional weather conditions shows a wide disparity in the energy savings that can be expected from a south-facing facade. These savings are most often well below a building’s average energy consumption and so a balance has to be found between the thermal resistance and the solar factor of glazing. In addition, the carbon footprint and cost of the most efficient glazing can considerably extend the environmental and economic payback time of a retrofit.This research shows that the potential for passive solar heating is significant but only as long as each architectural situation is analysed according to its specific context and function. This potential would be even greater if windows were designed and used as adjustable facade elements to suit variations in weather and use.