Even though better energy efficiency is great, the video highlights how policy for efficient housing requires minimising draft, which implies convection heating. This means that (at least on this topic) policy is still not addressing the really fundamental problems. To give an analogy: we did not get the modern computer by building a better vacuum tube, we did it by switching to an entirely different technology.

Kris de Decker has written extensively on this topic: why convection heating is problematic, which alternatives exist, and the problems with focusing exclusively on energy efficiency[0][1][2][3]. In short:

- On a meta-level, the actual problem we are trying to solve is not one of heating. Heating is a solution. The problem we are solving is how to stay warm. Framing it this way opens up entirely new options to explore.

- Air is a natural insulator with low thermal capacity, so an incredibly inefficient transport medium of heat. When heating up a cold room, the ambient air may heat up quickly, but the objects in a room can stay cold for very long.

- Convection heating requires that the heated air does not escape the room, so we end up with a trade-off between heating and fresh air. Personal anecdote related to this: I live in house that is so well-insulated that I cannot sleep with the window closed, feeling exhausted and out of breath in the morning (likely more due to the rise of CO2 than a lack of oxygen, but the result is the same). These days I sleep with the window open, under three layers of blankets, and the heating to a bare minimum.

- Convection heating also heats up the entire space, which is really wasteful: we really only care about heating the humans and other living things inside this space. To point out how ridiculous this really is: hot air naturally rises to the ceiling first, where nobody needs it. (admittedly, when a space remains damp and cold for a very long period of time, there is the problem of mould to consider. There are solutions for that, and they are more sustainable than wasting heat with convection heating)

- Because the heat in the air is absorbed at the windows, we have to put the convection heater next to it to get an even heat gradient in the room. So in other words: we put our heat source right next to the biggest heat-sink in the room.

Other methods of staying warm, like radiant heating or electrically heated clothing (yes, this exists) can bypass most if not all of these issues.

The problem is that we are trying to make modern lifestyle more efficient without radically questioning the lifestyle itself.

Elizabeth Shove had a good paper on this problem, although it can get quite dense[4]. Kris de Decker has a more accessible summary of it[3]. I'll highlight some stuff from Shove's paper:

> Programmes of energy efficiency are politically uncontroversial precisely because they take current interpretations of ‘service’ for granted. But in normalizing specific definitions of service, methods of evaluating efficiency carry normative assumptions about ‘need’ forward, invisibly bedding them into future programmes of research and development.

> In conclusion, the un-reflexive pursuit of energy efficiency is problematic not because it does not work, or because the benefits are absorbed elsewhere, as the rebound argument suggests, but because it does work– via the necessary concept of equivalence of service – to sustain, perhaps escalate but never undermine [...] increasingly energy-intensive ways of life.

> In response, it is tempting to call for greater interdisciplinarity, and new ideas are definitely needed. However, as Daniels and Rose perceptively observed, it is no accident that the field of energy efficiency is ‘devoid of any vision of history’ (Daniels & Rose, 1982) This is not something that can be fixed since it is an unavoidable consequence of how programmes of efficiency are conceptualized. In the end, it is impossible to imagine how organizations like the IEA, the EU or the UK Committee on Climate Change might come to recognize and explicitly evaluate their own role in making and shaping present and future ‘needs’. At the same time, and as historians might well point out, the ambition of reproducing ‘present’ standards of living, now and in the years ahead, is doomed to fail.

Better energy efficiency is important, but only one path. And on it's own, it will be as effective as insisting on building smaller vacuum tubes.

[0] http://www.lowtechmagazine.com/2015/03/radiant-and-conductiv...

[1] http://www.lowtechmagazine.com/2015/03/local-heating.html

[2] http://www.lowtechmagazine.com/2013/11/heat-your-clothes-not...

[3] http://www.tandfonline.com/doi/full/10.1080/09613218.2017.13...

[4] http://www.lowtechmagazine.com/2018/01/bedazzled-by-energy-e...