What is LEED? – Energy and Atmosphere

This is the fifth post in a series on the LEED green building rating system. The first post provided an Introduction to LEED, the second looked at the Sustainable Sites credit category, the third at the Location and Transportation credits, and the fourth at Water Efficiency.

LEED logo images

Energy and Atmosphere

Improving energy efficiency is one of the easiest ways to save money and improve the sustainability of a building. Therefore almost a third of the points available in LEED are found in this category.  Projects can earn these points by making the building more efficient that a code baseline building of similar size and shape, commissioning the building systems, and adding renewable power sources to the project.

Fundamental Commissioning and Verification

This is a required measure and must be completed to qualify for LEED certification.  Commissioning involves testing the equipment to verify that it is performing according to the design intent.  The commissioning agent, or person performing the testing, can be a member of the project team, but should not be directly involved in the building design.  Systems that need to be commissioned include: HVAC, electrical, plumbing, and renewable energy.  Exterior enclosures are also reviewed by the commissioning agent.

Fundamental commissioning includes: design review, development and inclusion of a commissioning plan into the construction documents, developing checklists and testing procedures, testing of the systems, maintenance of a trouble log, and reporting all findings to the building owner.

In addition, the project must develop an operations and maintenance plan designed to keep the building operating efficiently.  The plan should include: set points and schedules for the building system controls, a systems narrative, preventative maintenance plan, and an ongoing commissioning plan.

Minimum Energy Performance

This is a required measure and must be completed to qualify for LEED certification.  There are three options to meet this prerequisite.  The first involves providing a whole building energy simulation showing that the design will save at least 5% of the total energy use as compared to a code building of similar size and shape.  Projects must meet this requirement without including renewable energy sources.

The second option is to comply with the mandatory and prescriptive measures included in ASHRAE Standard 90.1-2010.  The standard provides requirements for  HVAC and service water heating requirements, including equipment efficiency, economizers, ventilation, and ducts and dampers.

Projects less than 100,000 square feet can earn this prerequisite by following the prescriptions of ASHRAE Standard 90.1-2010 Sections 1-3, which provide strategies and requirements for certain building systems.

Building-Level Energy Metering

This is a required measure and must be completed to qualify for LEED certification.  Projects must include whole building-level meters or sub-meters that can be aggregated to provide whole building use quantities for all energy consumption (natural gas, electricity, biomass, steam, propane, etc).  The project must also agree to provide this data on a monthly basis to the US Green Building Council for a five-year period.

Fundamental Refrigerant Management

This is a required measure and must be completed to qualify for LEED certification.  Projects should not use chlorofluorocarbon (CFC)-based refrigerants in new heating, ventilating, air-conditioning, and refrigeration systems.  If systems or equipment are re-used, a phase-out plan must be provided.

Enhanced Commissioning

This credit is worth 2-6 points.  Enhanced commissioning is performed in addition to the fundamental prerequisite above.  In order to receive this credit, the commissioning agent must be an independent contractor not already on the project team.  To earn 3 points, the commissioning process must include, in additional to the fundamental tasks: submittal review, verification that maintenance documentation and training is included in the construction documents, verification of training effectiveness and seasonal testing, reviewing operations 10 months after occupancy, and providing an ongoing commissioning plan.

An additional point can be earned by developing a plan to continually monitor data points to assess the performance of the energy and water use systems.  An additional 2 points can be earned by commissioning the building envelope for energy, water, indoor environmental quality, and durability.  The review should include: submittal review, inclusion of maintenance manuals and training in the construction documents, verification of training and seasonal testing, reviewing operations 10 months after occupancy, and providing an ongoing commissioning plan.

Optimize Energy Performance

This credit is worth 1-18 points.  Using whole-building energy modeling or prescriptive paths as described in the ASHRAE 50% Advanced Energy Design Guide for the type of building being used, provide energy efficiency measures to save from 6-50% over a code building.  Projects can earn up to 18 points if they use the energy modeling path, and up to 6 points for using the Energy Design Guide.

Advanced Energy Metering

This credit is worth 1 point.  Energy sources that are used by the whole building or provide more than 10% of the annual energy consumed by the entire building must be subject to advanced metering.  The advanced metering must include hourly use, energy consumption and demand, be collected on a local data server, and be remotely accessible.

Demand Response

This credit is worth 1-2 points.  Local utilities may provide the ability for a project to enroll in a demand response plan.  These plans broadcast the pricing of energy based on current demand, allowing projects to schedule their peak loads when the utility is cheapest.  Projects must participate in an existing demand response plan for a period of one year if it is available (worth 2 points) or provide the infrastructure to take advantage of one when it becomes available (worth 1 point).

Renewable Energy Production

This credit is worth 1-3 points.  Provide from 1-10% of the building’s annual energy consumption from renewable energy sources.  Using solar gardens or community renewable projects is allowed if the project owns the system or has leased it for over 10 years and it is in the same local utility area as the project.

Enhanced Refrigerant Management

This credit is worth 1 point.  Projects should either not use refrigerants, or only use those that have an ozone depletion potential (ODP) of zero and a global warming potential (GWP) of less than 50.  A weighted calculation can be used to determine if the project meets the requirement when certain refrigerants may be over the limit.

Green Power and Carbon Offsets

This credit is worth 1-2 points.  The project must enter into a contract to purchase Green-e certified green power or RECs (renewable energy certificates).  The programs must have come online since January 1, 2005 and the contract must be for at least five years.  One point is awarded for purchasing 50% of the building’s annual energy use from these sources, two points for 100%.

Next, we will look at the Materials and Resources credit category.

Source: LEED v4 for Building Design and Construction (updated July 1, 2014)