The ASHRAE Fundamental Handbook heat gain tables were last updated in 2009.
As a result of this, it is important to accurately assess the energy consumed by plug loads as overestimation can result in oversized HVAC systems increasing capital and operating cost while undersized systems result in thermal comfort problems for occupants. Plug load best practices guide: Managing your office equipment plug load. This leaves plug and miscellaneous loads as one of the main contributors to the overall energy consumption of buildings, accounting for up to 50% of the building's total energy consumption (NBI 2012 New Buildings Institute (NBI).
At the same time, the power consumption of the heating, ventilation, and air-conditioning systems is reduced due to the improvement in their energy efficiency. Recent advances in building envelope systems and fenestration have resulted in improved building envelopes, reducing both the air leakage and the heat transfer with the surroundings.
