The Pyramid of Conservation is a visualization of a home energy efficiency to-do list. It is designed to prioritize steps and develop an appropriate action plan.
It starts with the basics – a home energy audit – followed by low cost items such as programmable thermostats and hot water settings, before moving up through lighting, air sealing, insulation, windows etc.
Interestingly, high-cost, slow-return investments such as solar panels and residential wind turbines are right at the top of the pyramid – very much the ‘cherry on the cake’.
Energy efficiency is an input-output concept. It means ‘doing more with less’ and cannot be argued with. It’s good business sense and produces multiple benefits beyond a financial return [72, 77].
Energy conservation is a much more severe requirement and it requires ‘doing less’. This often involves trade-offs – flying less affects business or family relations. Absolute reductions in energy use could affect business productivity or citizens’ health and well-being.
It is risky to take the concept of reducing energy consumption too far. It can be safely applied to the technical performance of products or subsystems. It should not curtail necessary activities in projects, buildings or cities.
We implement efficiency measures, and electricity consumption increases. Have we done something wrong? Not necessarily: when we use electricity for more energy services, we’re comparing apples with oranges.
Energy efficiency works well as a technical metric for individual energy services. For systems such as homes, buildings, organisations or cities, in which energy consumption is the aggregate of many services, measuring efficiency is much more complicated (yet it is where the biggest savings are).
Note also the difference between energy efficiency (doing more with less) and energy conservation (doing less). The latter is the bigger challenge.