Building commissioning: a golden opportunity for reducing energy costs and greenhouse gas emissions in the United States

Abstract

Commissioning is arguably the single most cost-effective strategy for reducing energy, costs, and greenhouse gas emissions in buildings today. Although commissioning has earned increased recognition in recent years, it remains an enigmatic practice whose visibility severely lags its potential. The application of commissioning to new buildings ensures that they deliver or exceed the performance and energy savings promised by their design and intended operation. When applied to existing buildings, commissioning identifies deficiencies and the almost inevitable "drift" from intended performance over time, and carries out interventions to put the building back on course. More formally, commissioning is a systematic, forensic approach to quality assurance and performance risk management, rather than a technology per se. This article presents the world's largest compilation and meta-analysis of commissioning experience and the associated literature, comprising 643 non-residential buildings, 99 million ft 2 of floorspace, $43 million in commissioning expenditures, and the work of 37 commissioning providers. The median normalized cost to deliver commissioning is $0.30/ft 2 ($2009 currencies) for existing buildings and $1.16/ft 2 for new construction (or 0.4% of the overall construction cost). The one third of projects for which data are available reveal over 10,000 energy-related deficiencies, the correction of which resulted in 16% median wholebuilding energy savings in existing buildings and 13% in new construction, with payback times of 1.1 and 4.2 years, respectively. Because energy savings exceed commissioning costs, the associated reductions in greenhouse gas emissions come at a "negative" cost of −$110/tonne CO 2 for new buildings and −$25/tonne for new construction. Cases with comprehensive commissioning attained nearly twice the overall median level of savings and five times the savings of the least-thorough projects. Significant non-energy benefits such as improved indoor air quality are also achieved. Applying the median whole-building energysaving values to the US non-residential buildings stock corresponds to an annual energy-saving potential of $30 billion (and 340 Mt of CO 2 ) by the year 2030.

Uncertainties in energy consumption introduced by building operations and weather for a medium-size office building

“…For medium-size office building models simulated in different climates, the parameters with the largest impacts are lighting control, plug-load controls, VAV minimum settings, supply air temperature reset, and air side economizer control. In future research, it would be interesting to compare the uncertainties derived from simulation against empirical data from commissioning projects [19].…”

Assessment of Automated Measurement and Verification (M&V) Methods

“…Moreover, with NMBE ranging from approximately -1 to 4 for one quarter of the buildings in the dataset, and approximately -1 to -5 for another quarter, the results provide confidence that these M&V approaches will be applicable for many instances of multi-measure programs. This is because multi-measure programs commonly target larger savings, on the order of ten percent or more (for example, median retro-commissioning savings are 16% (Mills 2011)); with errors of just a couple of percent, there is less risk that savings will be 'lost in the noise'. In addition, the accuracies achieved in this study were for a fully automated case.…”

Factors Affecting Green Residential Building Development: Social Network Analysis

“…It is estimated that, in China, the construction industry consumes 40-50% of raw materials and about 20% of energy [1]. Although many functions have been submitted to reduce energy consumption [2][3][4], there are great numbers of high-energy consuming buildings in China, many of which are currently under construction [1]. Green building (GB), as one of the best practices of sustainable development in the construction industry, has drawn much attention [5][6][7][8].…”