Back in the 1990, whilst combining work at Delft University of Technology and the Energy Research Centre of the Netherlands, I studied the selection of 'energy saving building components'. Research in the next 25 years has taken me in different directions, but energy efficiency has always remained a core interest. So with the current energy crisis of 2022, what is there in this earlier work that might be of use who are trying to cope with the current high prices of energy?
The first thing that comes to mind is a general guideline that was promoted 25 years ago as the 'Trias Energetica'. Whilst old it still makes a lot of sense. It says that there are three principles to consider when making buildings energy efficient, which should be applied in the given order:
A second thought from my research is that whilst energy use may be an important consideration, we need to be aware that the thermal performance of a building may be linked to other performance aspects. Obviously, a simple and rigorous measure to save energy is to turn of your heating system, or to shut off radiators in rooms that are not used. However, this may have unintended consequences, such as health problems for the occupants (think of asthma). So care is needed when considering this approach. Similarly, it is often recommended to insulate cavity walls - however cavity walls also play an important role in keeping moisture out of the building. The outer leaf is often wet but as long as this is separated from the inner leaf by a cavity with circulating air there is no problem. Filling the cavity with insulation material may connect the wet outer leaf with the inner leaf, leading to serious moisture problems later.
A third important issue is that savings that can be achieved by individual energy saving measures mostly depend on the context. There are leaflets and advice making the rounds that one can save £145 per year whilst reducing carbon emissions with 640 of carbon per annum by insulating cavity walls, or save £200 per year by installing a new energy efficient boiler. Obviously, these savings completely rely on the starting point. Keep in mind that there is no point in putting double glazing in a bus shelter with an open door opening. Similarly, a highly insulated loft will not help you save much energy if the walls remain uninsulated, and windows are single glazing. In general it is worth keeping in mind that windows and doors are often the building elements that have the lowest resistance to the passage of heat.
For those that have an interest int he wide range of options, below is a list of energy saving building components that I compiled back in the past. Note that some of these 'measures' are architectural in nature, such as zoning of the building, or the area of glazing. Others align with building physics and science, such as thermal insulation in walls. Yet others are more the domain of systems and services. For more details on each alternative, and how it may help increase energy efficiency, please look at other sources of information such as that of engineering societies like CIBSE, REHVA or ASHRAE.