BREEAM is the Building Research Establishment Environmental Assessment Method for buildings provides an overview of an existing and established a checklist methodology currently used for the environmental evaluation of the building. This method includes the simultaneous evaluation of heat and electricity consumption that would assess the energy performance / efficiency of the buildings.
BREEAM is supposed to be the world's most widely used method of reviewing and improving the environmental / energy performance of buildings, where "BREEAM for Offices" is widely used for "reviewing and improving the environmental performance of office buildings". BREEAM is developed in the United Kingdom by the Building Research Establishment (BRE) in the 1990; it includes both a checklist assessment and a detailed methodology for both new and existing office buildings, regardless of occupancy durations and densities. In the existing buildings the assessment method can be carried out on existing occupied office buildings, by applying the "Management and Operation BREEAM" section.
Within the "Management and operation BREEAM" section of the assessment method, energy performance issues regarding heat and electricity efficiency are covered accordingly, and it is the review of these aspects that are of significance to the assessment of building energy performance.
Generally the assessment method, is largely based on checklist assessment criteria, credits the setting of minimum requirements with regards to the energy and Co2 emissions (GHG) of a building, as well as an annually based reviews and reporting procedures for both internal and external purposes. The other particular areas of interest in this assessment method are related to the "Health and well-being" and "Energy" sections. In the "Health and well-being" section, factors pertaining towards indoor air quality are assessed and ranked. The criteria in the section includes considerations for HVAC and natural air ventilation systems, the use of daylight management, load control for temperature adjustments, and the operational compliance of other mechanical services in the building including;
Heating /cooling systems
District hot water systems
The "Energy" section of BREEAM analyses both the heat and electricity consumption of an existing commercial office building. The assessment recommends audit procedures, performed after every three years, suggest improvements based on the audits and monitoring using previous data. The assessment tool similarly favors maintenance records covering the calibration and operation for all heating and cooling system controls.
It is of interest to note that this assessment tool is not offered in its entirety except through licensed BREEAM assessor organizations and the checklist assessment reviewed is based on a pre-assessment checklist. The purported aim of this methodology lies in rating the assessed building, in order to compare similar commercial office buildings against a BREEAM performance rating score.
4.3.2 LEED system
The Leadership in Energy and Environmental Design (LEED) for Existing Buildings is another method for the assessment of energy performance for existing buildings. It is currently used throughout the United States and is based on the original "LEED Green Building Rating System for Improving Building Performance through Upgrades and Operations".
In-contrast with the "BREEAM pre-assessment checklist", LEED for Existing Buildings is a "set of performance standards for the sustainable operation of existing buildings" which earns the "LEED 2.0" certification upon satisfactory compliance. In general, the system addresses building operations and performance improvements. The focus area of this system is within the sections of energy efficiency performance and system upgrades towards
The improvement of building energy
Indoor air quality
Lighting performance in relation to "green" performance standards
The LEED EB "Existing Building" system works in a similar manner to the BREEAM assessment, given that credits are awarded for compliance to certain performance standards, and the final score is tallied accordingly in a final scorecard. However, the public-version of this assessment standard is significantly more detailed than that of the BREEAM pre-assessment checklist.
In the "Energy and atmosphere" section, 3 prerequisites are to be satisfied before accreditation of the existing system can take place. These involve the verification and assurance that the "fundamental buildings systems and elements are designed, installed and calibrated, to operate as required" and for the establishment of a minimum energy performance for the base building systems.86 Compliance to these prerequisites are listed within LEED EB with methodological procedures, and are benchmarked on existing requirements based on the United States Environmental Protection Agency (US EPA) Energy Starâ„¢ label and the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) 90.1-1999 system.
Issues pertaining to the optimization of energy performance focuses on the intent of "rising levels of energy performance above the required standard to reduce the use of fossil fuels and to reduce the adverse impacts on the environment associated with excessive use of energy", with regulated energy components including the HVAC systems, building envelope and lighting systems, as per defined by ASHRAE.87 What is of interest is the unit of measure for performance - typically the energy metric, kWh of energy consumption per square meter of net building area - expressed in terms of the annual energy cost in US dollars in LEED EB. Requirements for compliance involve the provision of calculations showing that the actual energy efficiency and performance of the building exceeds those described by ASHRAE. 88
The "Indoor environmental quality" section focuses largely on the establishment of indoor environment conditions for the comfort of the occupant. It includes sections on the establishment of minimum indoor air quality performance and the provision of an adequate level of lighting, ventilation, temperature control, hazardous chemical control and carbon dioxide monitoring for occupant health and comfort.89 While this may not affect the energy performance of a building directly, the gain of energy efficiency and low energy use in a building must not be achieved through a compromise of these standards, therefore, the review of the indoor environment is important in the assessment of energy performance in a building.