Update to SI426 Audit Obligation from October 11th 2026
New changes have been made to SI426 Energy Audit Obligations
There is an important SI426 energy audit update for Irish businesses. The obligation to carry out an energy audit no longer depends on your employee numbers and/or turnover, it now depends purely on how much energy your business uses.
This article covers:
What changed with the SI426 energy audit update
Who now faces a mandatory energy audit in Ireland
What newly obligated businesses should do next
What the SI426 energy audit is
How Watt Footprint can help with SI426
What Is the SI426 Energy Audit?
SI426 is the Irish regulation that transposes the EU Energy Efficiency Directive. It sets out which businesses must carry out an energy audit. This SI426 audit is to be carried out every four years. An energy audit is a structured review of how your business uses energy across heat, electricity and transport. It identifies where energy is being wasted and where savings can be made.
For obligated businesses, the SI426 energy audit is not optional. It is a legal requirement, and it must be carried out to the standard the regulation sets.
What Changed With the SI426 Energy Audit Update on 11 October 2026
Until now, the SI426 audit obligation was tied to company status. If your business was not an SME, you were obligated to carry out an energy audit. SMEs were outside the obligation. That has now changed. The obligation is based purely on energy consumption. You can see the changes below:
New SI426 Audit Criteria
All companies with energy consumption between 10TJ & 85TJ will be obligated to complete SI426 Energy Audits, irrespective of if they are defined as SME or Large Industry.
Old SI426 Audit Criteria
Companies who had at least 250 employees OR Annual turnover exceeding €50million and Annual Balance sheet exceeding €43million were obliged to carry out an SI426 Energy audit.
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Who Now Faces a Mandatory Energy Audit in Ireland
The change brings a new group of businesses into scope. Newly obligated companies with energy consumption between 10 TJ and 85 TJ a year must complete their first energy audit no later than 11 October 2026.
If terajoules are unfamiliar, here is a rough guide: 10 TJ is about 2.8 GWh a year, and 85 TJ is about 23.6 GWh. Your energy bills or meter data will show your annual consumption, which makes it straightforward to see where you sit.
What Newly SI426 Obligated Businesses Should Do Next
If the energy audit obligation now applies to you, a few practical steps will keep you on track:
Confirm your annual energy consumption across all sources to see where you sit against the 10 TJ threshold.
If you are in the 10 to 85 TJ band, you need to start get an SI426 Energy audit as soon as possible.
Appoint a qualified energy auditor and gather your consumption data so the audit can run smoothly.
Acting early gives you time to meet the energy audit obligation in Ireland without a last-minute rush, and to act on what the audit finds.
Watt Footprint SI426 Consultancy
Not sure whether the SI426 obligation applies to you? Watt Footprint manages, consults and conduct SI426 Audits with companies that meet the SI426 energy audit requirement. From checking where you sit against the threshold to guiding you through the audit itself, we take the uncertainty out of compliance.
Book a call and we will help you work out exactly where you stand
Kevin Butler
Senior Energy Expert
Manufacturing Energy Efficiency
The SI426 audit obligation no longer depends on SME status. It now depends on energy use, bringing businesses between 10 TJ and 85 TJ into scope.