Book Assessment

Home Energy Efficiency and Sustainability​ Assessors

Accredited with NatHERS and DELWP

Building Shell

Building shell (or envelope) is the physical barrier between building interior and outside space. It consists of floor, subfloor, walls, ceilings, roof and insulation if any. Openings (doors, windows), penetrations (vents, exhaust fans) and any other features that affect heat transfer between the house and outside space are also considered part of the building shell.  

Fixed Appliances

Fixed appliances are heaters, air conditioners and hot water systems, permanently attached or built into the building shell. 

Plug in App​liances

Plug-in appliances are devices connected to power source, constantly drawing power - like fridges, freezers, chargers, etc and appliances working in  standby mode (TVs, sound, AV, microwave, etc). Appliances using power on demand (lamps, toasters, power tools, hair dryers, etc) are generally not considered in our reports unless they consume considerable amount of energy when used. 


Behavioural power usage is due to "human factor" - individual preferences or habits of people living in the house. Adjusting the way the power is used, without impact on comfort or health, could lead to developing power saving habits (closing door to unused rooms, turning off the lights when not in use, etc)