When I was doing my postgraduate information security course with the Open University a few years ago, I came across the concept of folk models. It was a term used by Willett Kempton in a number of papers, such as Variation in Folk Models and Consequent Behaviour (American Behavioral Scientist, 1986). For example, how people think their heating system works (the folk model) affects how they use it and whether they are more likely to turn up the output temperature or the thermostat setting.

This came back to me recently when we had a heating engineer round. We’d been finding the amount of water wasted while waiting for it to heat up perturbing and we wondered if the boiler was at fault. Particularly unpleasant was the way the shower would take ages to heat up, no matter how you fiddled with it; sometimes, we’d just give up. It turns out that the fiddling was the problem and our folk model was leading us astray.

In our previous house, the boiler was in the kitchen, with no more than 2m of pipe to the kitchen sink and not a lot more going up to the bathroom above. Apparently, that is ideal siting for a combi boiler. In the new place, it sits in the room I use as my studio. The nearest tap is 5-6m away along the pipes and some are a lot further still, which means a lot of cold water to flush and a good length of cool pipe to run the heated water through before it gets to the outlet.

With the shower, the approved technique is to set the temperature you think you want before turning on the shower to full power. There is some waiting involved but adjusting the heat and power during operation is less ideal. The shower tries to draw differently from the boiler and it takes time for the adjustment to take effect by which time we’ve probably tried tweaking the controls some more. So far, that new information, adjusting for the fact that our previous system disguised the weaknesses of the design, seems to be working out and I’m taking a lot less unwanted cold showers as a consquence.