GN4.12:Energy performance monitoring

Continued monitoring for energy performance is normally led by a property manager, with input from the facilities manager.  Technical support from an energy manager or other competent individual is usually central to the process. 

Continued monitoring for energy performance involves consideration of the following four steps: 

It is important to be able to measure a property’s energy consumption profile frequently, regularly and accurately.  Reliable advanced metering and sub-metering enables detailed and effective energy monitoring and analysis. 

Key performance indicators (KPI) support a property’s continuous improvement in energy performance.  KPIs provide visibility of the fulfilment of energy objectives and drives improvement by encouraging energy efficiency measures to be delivered 

Good energy KPIs will be visible to stakeholders.  The meaning of KPIs should be clear, including the extent to which a property is making progress in relation to the performance being measured through the KPIs.   

There are two types of KPIs that an energy manager should consider: 

Strategic KPIs: High-level or industry-level measures. 

A strategic KPI that is commonly used to track and benchmark a building’s performance is the energy usage intensity (EUI). 

The EUI expresses a building’s energy use as a function of its size.  EUI is typically expressed as energy per square meter per year.  This calculated by dividing the total energy consumed by a building in a year by the building’s total gross floor area.  EUI can be defined as a building’s energy performance indicator. 

As a building’s energy usage intensity is related to the building’s total energy usage, it is important that accurate data from the main utility meters can be obtained.  

By using EUI, a building’s energy performance can be benchmarked against comparable and/or average buildings.  

By using data from advanced sub-meters, it is possible to review how system components, such as lighting and HVAC systems, for example, compare to industry standards. 

For example, comparing a property’s EUI against CIBSE’s Guide F: Energy Efficiency in Buildings, which includes industry benchmarks for different building types and system components.  

To benchmark buildings, The Real Estate Environmental Benchmark (REEB), a publicly available operational benchmark of environmental performance for commercial property in the UK, is also beneficial.  

Control-specific KPI: This focuses on specific plant and equipment. 

For example, a KPI could be set for optimal setpoints for HVAC systems, so that deviations from optimal parameters can be reviewed.  Deviating from optimal parameters can be due to fault equipment or control settings which would increase a property’s energy usage unnecessarily. 

Monitoring and analysing collected energy consumption data, profiles and patterns and comparing these to KPIs benchmark helps to identify areas of energy wastage.  In turn, this enables opportunities for energy performance improvement to be identified and evaluated, and progress towards energy targets to be assessed.  

As part of this, it is important that energy usage patterns are reviewed though consideration of annual, monthly and seasonal changes in demand.  By using accurate data from advanced meters, energy managers can investigate data at a granular level to support understanding changes in peak load times and baseload.  

Energy reports are important for keeping track of a property’s energy performance and the extent to which progress is being made against targets.  Compiling an energy report can also encourage on-going energy monitoring by a range of property stakeholders. 

Energy reports may be in the form of dashboards that can be used to engage with stakeholders, including property managers, employees and occupiers, who can use the information contained within the reports to act on energy saving recommendations. 

Dashboards should be shared with stakeholders on a regular basis (typically monthly), and should present information in an understandable and engaging way. An example of an energy dashboard which demonstrates how monthly consumption changes over time and how a building is performing against a target can be seen below.