The most common way of categorising energy conservation measures is by cost:
- Low- to No-cost measures
- Medium-cost measures
- High-cost measures.
Low- to No-cost measures require very low, if any, investment and design input. Examples of such measures are: modification of thermostat settings, use of windows for natural ventilation and shifting of activities to off peak hours. Medium-cost measures require some level of investment to cover for the works expenditure and therefore some time before they are ready for implementation. However, they still require little or no design input. For the high-cost measures a detailed study and design but also a considerable amount of investment are required for their implementation.
A common classification of energy related behaviours is:
Purchase-related behaviours refer to the purchase of appliances and systems or even alterations to the structure of the building. Usage-related behaviour has to do with the frequency, duration and intensity of use of appliances and systems and of the building itself. Maintenance-related behaviour involves the maintenance undertaken on systems and appliances to ensure their energy efficiency.
More details and literature on classification of energy related behaviours and energy conservation measures can be found here.