When considering the use of solar technologies, in all cases the surface area available for collecting solar energy needs to be balanced against the demands for electrical power or hot water. Thus, a single-storey building may have more potential for using solar energy than a 10-storey building. However, there are also innovative ways to increase the surface area available for solar collection. One option is the use of PV laminates on the glazing, as these will provide solar shading and generate electricity at the same time. So such technology is well worth considering when the project includes a need to reduce solar heat gains — in a highly glazed building for instance. It is also becoming increasingly common to introduce brise soleil in refurbishments (and new-build projects) to reduce solar heat gains. Given that brise soleil should be at the optimum angle to provide shading, its is then also optimally positioned to collect solar energy via PVs or evacuated tubes for hot water. Nor do these principles need to be confined to major refurbishments. For example, many retail stores have reduced energy wastage by the simple expedient of constructing a porch outside their doors. So why not roof the porch with solar thermal panels and give the hot-water systems a renewables boost at the same time? Where variable heat sources are being used for DHW, one of the biggest challenges is to cope with the variable heat input while maximising the renewable energy available. In some cases, refurbishment may allow the opportunity for extensive, super-insulated underground hot-water storage, which could iron out much of the inter-seasonal fluctuation. There is also scope for combining PVs with grass roofs. It is well established that grassing a roof with sedum will help to absorb heat before it warms the building fabric, as well as providing some evaporative cooling to the building. It is also established that PVs are more efficient at lower temperatures. So if PV panels are mounted around the perimeter of a grassed roof, the cooler micro-climate will increase the energy collected by the PVs while retaining the other benefits of a sedum roof. While most solar thermal installations are designed to supply or pre-heat domestic hot water (DHW), there is the potential to use the hot water to drive absorption chillers. On the plus side, this provides a balanced demand scenario, as most hot water would be generated when cooling demands are highest. On the negative side, absorption chillers have a low COP, are expensive and have demanding maintenance requirements. Rather than considering every single option, which it certainly has not done, the purpose of this article has been to provoke and encourage a structured and reasoned approach to determining the most suitable options. Considering fabric improvements first and thinking about the characteristics of the location second are certainly good starting points. Ant Wilson is a director with Faber Maunsell.