Document Type : Original Article


1 School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran

2 Institute for Environmental Design and Engineering, University College London (UCL), London, England


Auditing electrical energy in buildings is a feasibility study consisting of a comprehensive assessment of a building's electrical utilities in order to optimize energy consumption. In this paper a bottom-up method to estimate electrical loads is formulated that could help in disaggregating electricity use to specific end-uses in the absence of sub-meters in existing buildings. This method can be used for detailed benchmarking and identification of improvement opportunities. Implementation of the method in an office building, located in Tehran, shows that a satisfactorily match (94.66% for off-peak, 88.69% for mid-peak and 94.46% for on-peak) exists between the calculated loads with the data extracted from electricity bills. The building electrical energy auditing shows a maximum share of consumption for office equipment (32%) and a lower consumption for lighting (28%), space heating and cooling (17%), domestic hot water (12%) followed by catering and other electricity end-uses (11%). Through interpreting the energy auditing results, strategies for increasing energy efficiency has been suggested.


1.    U.S. Green Building Council (USGBC), Buildings and Climate Change,
2.    D. Bouley, Estimating Data Center's Electrical Carbon Footprint, Schneider Electric's Data Center Science Center,
3.    U.S. Energy Information Administration, 2015, Annual Energy Outlook with projections to 2040.
4.     M. Airaksinen, P. Matilainen, 2011, A Carbon Footprint of an Office Building, Energies 4, 1197-1210.
5.     J. Field, J. Soper, P. Jones, W. Bordass, P. Grigg, 1997, Energy performance of occupied non-domestic buildings: Assessment by analysing end-use energy consumptions, Building Services Engineering Research & Technology, 18. 1, 39-46.
6.    N. Fumo, P. Mago, R. Luck, 2010, Methodology to estimate building energy consumption using energy plus benchmark models, Energy and Buildings 42, 2331–2337.
7.    Y. Zhu, 2006, Applying computer-based simulation to energy auditing: a case study, Energy and Buildings 38, 421–428.
8.   T. Catalina, J. Virgone, E. Blanco, 2008, Development and validation of regression models to predict monthly heating demand  for  residential  buildings,  Energy  and  Buildings  40, 1825–1832.
9.   A. Hernandez, F. A. Sanzovo, Use of simulation tools for managing buildings energy demand. Available from: main.html.
10.   F.  W.  H.  Yik,  J.  Burnett,  I.  Prescott,  2001,  Predicting  air- conditioning energy consumption of a group of buildings using different heat rejection methods, Energy and Buildings 33, 151–166.
11.   S. Chirarattananon, J. Taveekun, 2004, An OTTV-based energy estimation model for commercial buildings in Thailand, Energy and Buildings 36, 680–689.
12.   Y. Pan, Z. Huang, G. Wu, C. Chen, 2006, The application of building energy simulation and calibration in two high-rise commercial buildings in Shangai, Second National IBPSA-USA Conference.
13.   F. Gugliermetti, G. Passerini, F. Bisegna, 2004, Climate models for the assessment of office buildings energy performance, Building and Environment 39, 39–50.
14.   F. S. Pedrini, R. Westphal, Lamberts, 2002, A methodology for building energy modelling and calibration in  warm climates, Building and Environment 37,  903–912.
15.   F.   S.   Westphal,   R.   Lamberts,   2005,   Building   simulation calibration using sensitivity analysis, Ninth International IBPSA Conference.
16.   ASHRAE Audit Procedures, 2012,, Retrieved - 03-29.
17.   IEA EBC Annex 11, 2012,, Retrieved -03-29.
19.   P. Ajay -D- Vimal Raj, M. Sudhakaran, P. Philomen -D-Anand Raj, 2009, Estimation of Standby Power Consumption for Typical Appliances, Journal of Engineering Science and Technology Review 2. 1, 71-75.
20.   International Energy Agency, 2001, Report on things that go blip in the night standby power and how to limit.
21.   A.  Meier,  1999,  Standby  power  –  A  quiet  use  of  energy, CADDET Energy Efficiency newsletter, No. 4.
22.   A. C. Menezes, A. Cripps, D. Bouchlaghem, R. Buswell, 2013, Benchmarking small power energy consumption in UK office buildings: a review of data published in CIBSE guide F, Building Services Engineering Research and Technology, 34. 1, 73-86.
23.   H. Hussain Sait, 2013, Auditing of energy consumption of an educational building in hot and humid area, Energy Conservation and Management 66, 143–152.
24.   S. Chirarattananon, J. Taveekun, 2003, A technical review of energy conservation programs for commercial and government building in Thailand, Energy Conservation and Managment 44, 743–762.