Editorial

We hear a lot about net zero carbon buildings but much less about net positive carbon ones in which there is energy spare to feed back to the grid. It was welcoming, especially at this time of very high fuel costs, to read the article Cutting Bills with Energy-Positive Homes in the August 2022 issue of the CIBSE Journal. Research on this topic has been carried out at Cardiff University in recent years and so unsurprisingly these 14 new low-cost social homes are located at Stormy Downs in Bridgend and are part of the Welsh Government’s three-year Innovative Housing Programme. The homes are passively designed for low energy and use solar PV, lithium-ion battery storage and heat pumps to collect, store and distribute the energy flows. There are no other heating or cooling appliances. The construction cost is about 35% higher than the average build cost for Building Regulations designed social housing but the typical annual running costs are − £59 as reported by Hoare Lea. As energy loads for the building decrease to very low levels the energy loads for equipment become even more significant and these are loads that are highly affected by the homeowner in using, for example, washing machines, fridges, dishwashers, ovens, plug-in sockets and towel rails. To attain carbon positive, which results in money being paid back to the consumer, residents need to be aware of how they can manage their energy consumption pattern. Care is also needed in choosing the tariff offered by the energy supplier. Windows play a big role in achieving healthy and happy environments to work in. They are the entry points for natural light which is so important for health and wellbeing. They provide us with views which can offer interesting stimuli to our minds so offsetting the close eye focus needed for seeing computer screens which can be tiring. But then the downsides are overheating which can result in high energy consumption, glare and the transmission of UV radiation. In the August 2022 issue of Physics World, there is an article titled A Novel Window into Smart Glass. Part of this insight, which covers a range of research on increasing the performance and functionality of glass, is focused on windows for buildings. Electrochromic windows are not new but thermochromic ones are more recent. The window energy performance is controlled by changes in temperature rather than voltage. This is achieved by using a coating of vanadium dioxide or other materials such as perovskites (semiconductors which when light is incident on them transport electric charge and are used in the latest high-efficiency solar cells) which undergo phase transitions hence becoming less or more transparent to solar radiation. There is still more research needed but early indications are that thermochromic windows could offer significant energy savings. Now these are brief headlines of some research which has been reported in the last month.