Activity metrics are used to determine your organisation’s energy performance. Learn which metrics are required.

Using activity metrics to track energy performance

An activity metric is a measure of the activity that your organisation undertakes. Measuring energy use alone does not enable you to determine if energy is being used efficiently or not. Activity metrics are required in order to understand the energy performance of an organisation, and to track your progress towards the 2020 target using an Energy Performance Indicator (EnPI).

A simple example of an activity metric used for an EnPI

If a coffee shop reduces its electricity consumption by 5% from the previous month, it may appear to be managing its energy consumption well. But if the 5% reduction coincides with a 20% drop in the number of cups of coffee sold, then the energy used per cup of coffee sold has actually increased. Therefore, the energy performance has worsened.

  • Activity metric: Numbers of cups of coffee sold
  • Energy Performance Indicator (EnPI): The energy used per cup of coffee sold

Activity metric requirements for M&R

This information is relevant to public bodies only, schools have separate guidance on Activity Metrics. You must report annual values for each of the following activity metrics:

  • A robust organisation-level activity metric of your choice. This is a key data input that is used to track your organisation's progress towards the 2020 target. It is important to choose a good activity metric for this.
  • The total useful floor area (TUFA) of your facilities.
  • The number of full-time equivalent (FTE) employees in your organisation.

Some organisations can use one or other of the TUFA or FTE employee activity metrics as their main metric for tracking energy performance.

Why use it?

The total useful floor area (TUFA) metric is based on a key driver of energy consumption for many organisations (i.e. buildings) and is relevant for other energy reporting frameworks, e.g. Display Energy Certificates (DECs).


This methodology is identical to that used to calculate floor area for DECs – in compliance with European Union (Energy Performance of Buildings) Regulations 2012 (SI 243 of 2012).

TUFA should only be calculated for buildings which use energy to condition the indoor climate e.g. space heating, cooling, ventilation. Once you have calculated the TUFA for each relevant building, add the values together to calculate a total organisation-level TUFA in square meters (m2).

TUFA is based on the building area measurement specified in Irish building legislation. This is the same as the Gross Internal Area (GIA) commonly used in commercial property surveying, and for which measurement conventions are based on the SCS/IAVI Measuring Practice Guidance Notes. The method to measure TUFA is also set out in Technical Guidance Document L of the Building Regulations, which states that 'linear measurements for the calculation of wall, roof and floor areas and building volumes should be taken between the finished internal faces of the appropriate external building elements'.

In this convention:

  • The area of sloping surfaces such as staircases, galleries, raked auditoria, and tiered terraces should be taken as their area on plan
  • Areas that are not enclosed such as open floors, covered ways and balconies are excluded

Some building sectors commonly use alternative measures of area, notably Net Lettable Area (NLA) for the commercial office sector, and Sales Floor Area (SFA) for retail premises. Where these are the only measurements available, then the calculation may use standard, conservative, conversion factors to obtain TUFA from NLA or SFA.

What is it?

One full-time equivalent (FTE) employee corresponds to one full year of work by one person. Your HR function should be able to give you the relevant FTE employment figures for each year and explain the methodology used.


It is important that your FTE employment data is calculated in the same way every year. If your organisation changes the basis for the FTE employment calculation, then you will need to either:

  • Continue to calculate FTE employment data using the ‘old’ method for the purposes of energy reporting
  • Re-submit FTE employment data calculated using the ‘new’ method for your chosen baseline year(s) onwards.

You can also optionally report up to three additional activity metrics that correspond to your electrical, thermal and transport consumption. These metric values are used to calculate energy performance indicators for these elements of your consumption. These optional activity metrics are not used to track your organisation's progress towards the target.

Organisation-level activity metric

When you are using the M&R system it suggests one or more standard activity metrics that should be appropriate for your organisation. Because all public bodies are different, the suggested metrics may not be optimum for your organisation. So, if you prefer you can specify your own alternative activity metric.

Choosing an alternative activity metric

You should select an organisation-level activity metric that accounts for changes to the main drivers for energy consumption across your entire organisation over time. Ideally, the activity metric should quantify the key activities that affect energy use. The most important characteristics for a good activity metric are that it is:

  • Relevant to what actually drives energy consumption
  • Well defined
  • Understandable
  • Measurable

Data availability is also a key factor, especially for large, complex and multi-site organisations. If you believe that your choice of activity metric could be improved or you are considering using alternative activity metric, SEAI’s Activity Metric Masterclass and Mentoring Service can support you through this process.

Composite activity metrics

Determining a single organisation-level activity metric for large or complex organisations can be difficult because different aspects of the organisation’s activity consume different amounts of energy.
Because of this you have the option to generate and use a composite activity metric to track your performance.

You can develop a composite organisation-level activity metric based on more than one subactivity metric. The scale of each subactivity metric’s contribution to the overall activity metric is specified by you, and should be based on each subactivity metric’s share of the overall energy consumption. For example, a local authority could build a composite activity metric based on the following two subactivity metrics:

  • No public lights – weighted at 20% because 20% of baseline consumption is used for public lighting
  • Population served (80%)

The equation used by the system for calculating the composite organisation-level activity metric based on your inputs is:


  • Each ‘Subactivity i’ represents a subactivity undertaken by the organisation. You report an annual value for each subactivity.
  • ‘Weighting i ’ is a weighting applied to subactivity i. The same weightings are used for each year from the baseline period onwards. The sum of the weightings must equal 1.0.
  • ‘x’ is the total number of subactivities incorporated into the composite activity metric.

Using this approach will give an activity metric for the baseline period equal to 1,000. You can opt to use a composite metric by selecting ‘Use other Activity metric’ in the M&R system and then clicking ‘Composite Activity Metric’. You will then be prompted to enter your subactivities and weightings.

This approach is only appropriate where all of the subactivities have been undertaken since the baseline period.

Calculating values for your activity metric

Remember that your organisation-level activity metric will be used to track your energy performance against the target, so having robust data is essential. So, while the way in which you calculate your activity metric is up to you, it is essential that you calculate it in a robust manner, that you do so in the same way each year and that the values reported correspond to the relevant reporting year. If you do not, then your energy performance will be distorted. For this reason, you should retain records of your calculation of your activity metrics for each year.

Changing an activity metric or calculation method

You can change your preferred activity metric or the way in which you calculate an activity metric. However you will have to re-submit valid data for any new activity metric for your chosen baseline and every subsequent year. Likewise, you will have to re-submit metric data for historical years on the basis of the ‘new’ calculation methodology.

Organisations that change activity metrics or calculation methods will be the focus of greater scrutiny in terms of data verification assessment.

Local authorities

For local authorities, the transition of water services assets to Irish Water resulted in a significant change to the activities that influence their energy consumption. Up to 2013, the provision of water services was a significant driver of local authority energy consumption. Since the beginning of 2014, this no longer materially affects local authority energy consumption in the sector.

In recognition of this structural change to the sector local authorities can use one activity metric for the period up to and including 2013, and a completely different one from 2014 onwards. This enables them to track their energy performance on a robust basis from their baseline, through the transition to Irish Water and up to 2020. Either or both metrics can be composite metrics.

Two activity metrics for two periods

The first activity metric applies from the start of your baseline up to the end of 2013. The second applies from the start of 2014 onwards. This coincides with the transition to Irish Water. You cannot specify a different break-point or transition year for the two metrics.

In general, your local authority can choose to use one metric or two separate metrics for the two periods. However, if either of the following applies, you should use separate metrics for the two periods :

  • You use a metric (including a composite metric) for the period prior to 2014 that explicitly incorporates water services activity, e.g. if your composite metric incorporates a subactivity directly related to water services.
  • You use a metric (including a composite metric) for the period after 2013 that explicitly incorporates other activities undertaken by your local authority, but not water services, e.g. if your composite metric incorporates subactivities for public lighting and/or buildings, but not water services.

Separate metrics are not required if you use population served as your metric, although you may still opt to use separate metrics.

Appropriate activity metrics

If you are using separate activity metrics for the two periods:

  • The ‘pre-2014’ metric must reflect the fact that your local authority provided water services during this period. The provision of water services need not be explicitly included (e.g. population served is acceptable), but it cannot be explicitly excluded (e.g. a metric based on public lighting and floor area alone is unlikely to be appropriate).
  • The ‘2014 onwards’ metric must not be based on water services activities.

Population served is an acceptable metric for either or both periods, but it may not be optimum for all local authorities.

Reporting two activity metrics for two periods

To facilitate the transition from one activity metric to the other, you must report data for both metrics for 2013. So, you must report data for:

  • Your ‘pre-2014’ activity metric for every year from the start of your baseline up to 2013 (inclusive)
  • Your ‘2014 onwards’ activity metric for every year from 2013 onwards

Organisations that have fundamentally transformed

There are some very rare instances where it is impossible to select a robust metric that is valid for both the baseline period and the most recent reporting year. This may be because the drivers for energy consumption within the organisation have fundamentally transformed over the period, e.g. the main activity currently undertaken by the organisation was not undertaken during the baseline. Consider organisation ABC:

In 2009, 100% of ABC’s consumption was in its single office building, occupied by a small number of staff. Since the, staff numbers and office size have remained more or less constant. However, its energy consumption has increased dramatically and is now dominated by significant process operations at multiple sites. ABC is struggling to pick a good activity metric. Choosing FTE employees or TUFA may be appropriate for the office-based activities but they are not appropriate for the process operations. ABC’s process operations can be quantified but they were not undertaken in 2009, so an EnPI could not be calculated for 2009. For the same reason, using a composite metric would not work.

If your organisation’s history is similar to that in the example and you cannot select an activity metric that is valid for both the most recent baseline (2009) and the most recent reporting year because your energy consumption is now driven predominantly by an activity that was not undertaken in 2009, then you should contact SEAI setting out your circumstances.

Further information

Census years

Population served is the suggested organisation-level activity metric for local authorities. There is census data available for the population in each individual local authority area for the following years:

Approaches for other years

The following approach should be used to calculate population for the other years:

  • 2001: Interpolate between the 1996 and 2002 census data assuming a constant rate of change in each of the intervening years.
  • 2003, 2004 & 2005: Interpolate between the 2002 and 2006 census data assuming a constant rate of change in each of the intervening years.
  • 2007, 2008, 2009 & 2010: Interpolate between the 2006 and 2011 census data assuming a constant rate of change in each of the intervening years.
  • 2012, 2013, 2014 & 2015: Interpolate between the 2011 and 2016 census data assuming a constant rate of change in each of the intervening years.

Approach for 2017

Project from the 2016 census value for your county using whichever of the following you believe to be most representative for your county (or project forward on the basis of an alternative, justifiable figure): 

  • The average annual % change in population for your county between the 2011 & 2016 censuses. You can calculate this by dividing the value shown in the CSO population statistics for 'Percentage change since previous census (%)' for your county by 5.
  • 2016 population plus 1.1%, which is based on the CSO’s preliminary estimate of change in the national population between the 2016 & 2017 (as of December 2017)

Different types of organisations use electricity for different purposes. For example, if your organisation’s main energy use is in buildings, then most of your electricity use is probably for lighting, IT and, possibly, heating and air conditioning. In this case a good activity metric might be the number of people that benefit from the energy service provided by the electricity (e.g. FTE employees, FTE students) or else the total useful floor area (TUFA).

On the other hand, other organisations use a lot of electricity for non-building uses. For example, local authorities consume significant amounts of electricity providing public lighting. For these organisations, the best activity metric might also be based on the number of people that benefit from the energy service. Your organisation might use electricity differently; you should bear this in mind when considering what activity metric to use.

In most public bodies, the vast majority of thermal energy is used for space and water heating. Therefore a good activity metric is often the number of people that benefit from the heating, e.g. FTE employees, FTE students (education sector). An alternative metric is the total useful floor area (TUFA).

Your organisation might use thermal fuels differently; you should bear this in mind when considering what activity metric to use.

Transport fuels are used to transport persons or goods. Therefore, good activity metrics are:

  • km-travelled, e.g. for a fleet of cars
  • passenger-km travelled, e.g. for public transport
  • Passenger journeys, e.g. for public transport (but not as good as the above)
  • tonne-km travelled, e.g. for freight

Your organisation might use transport fuels for more specialist purposes; you should bear this in mind when considering what activity metric to use.