Two things prompted this blog post. The first is an experiment I’ve been doing on my housemates, in which I go round switching lights off when people aren’t in a communally used room (which I count as kitchen, bathroom, front room, study). I have done this on 10 evenings when I’ve been home over the last month. Every evening I have done the experiment, I’ve switched off at least 10 lights. Rather disappointing given that we would all self-identify as being environmentally friendly. Anyway… I’d vaguely been wondering about lighting, and then yesterday whilst looking for data on energy consumption by fuel type for a lecture I was giving, I came across some interesting data from BEIS on appliance ownership. It’s from their annual publication “Energy Consumption in the UK”, and is reproduced below.
As is obvious from the table, we own far more electrical appliances than we did in 1970. The increase in appliance ownership is particularly striking in two sectors; lighting, and consumer electronics. The data on lighting appliances is shown in more detail below (the BEIS spreadsheet I got the data from is available here).
We can see that the increase in ownership of both energy saving bulbs and halogens corresponds closely with the decline in incandescent light bulbs. The EU phase out of incandescent bulbs dates from 2009, and this accelerated the shift that had already started. The increase in halogens would be concerning from an energy efficiency perspective, but they are being banned from sale in 2018, and it’s likely that LEDs (which are much more energy efficient) will fill this void.
The other striking thing about the data is that we have a lot more lights than we did in 1970 (16 per household in 1970, compared to 27 in 2016). What isn’t yet clear is the rate at which improvements in switching, wireless technologies and controllability of lighting are going to occur. It’s certainly the case in my household that a lot more lights are being left on than used to be the case, and this seems to be largely due to preferences relating to ambience and task lighting, combined with the fact that it then becomes necessary to hit several light switches in different parts of the room. Locations of light switches on mains electrical circuits feature in building regulations (there needs to be a light switch by the entrance to a room), but it is difficult to see how regulatory requirements can keep pace with changes in consumer purchases and preferences for lighting.
My guess is that at some point in the next 5 years, our hunger for more lights will outstrip the use of more energy efficient lighting, and that unless the controllability of lighting improves significantly, the total energy use from lighting appliances is going to go up.