30-Second Overview
Estimated Annual Consumption (EAC), also known as Annual Quantity (AQ), is the estimated amount of natural gas your business will use over 12 months, measured in kilowatt-hours (kWh).
- Existing gas connections: EAC is calculated using historical gas consumption data.
- New gas connections: EAC is estimated using the gas appliances installed, their expected consumption and operating hours.
- Annual reviews: Gas Networks Ireland reviews EAC annually, with revised figures taking effect from 1 October.
- Why accuracy matters: EAC helps determine your business gas tariff classification, making it important that the estimate reflects your actual gas requirements.
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What Is Gas Estimated Annual Consumption (EAC) or Annual Quantity (AQ)?
Estimated Annual Consumption (EAC) is the estimated amount of natural gas your business is expected to use over 12 months, measured in kilowatt-hours (kWh). It is also known as Annual Quantity (AQ).
Gas Networks Ireland determines EAC using historical gas consumption data. For new connections without a consumption history, the estimate is based on the expected gas requirements of the premises.
EAC is used by gas suppliers to determine your business gas tariff classification and applicable pricing structure. It is an estimate of annual consumption, not the actual quantity of gas you will necessarily use.
How Is Business Gas Estimated Annual Consumption (EAC) Calculated?
Gas Networks Ireland calculates Estimated Annual Consumption (EAC) using historical gas consumption data or forecasted usage for new connections.
Existing Gas Connections
For businesses with an established gas consumption history, EAC is calculated using previous meter readings and recorded consumption. This provides an estimate of the quantity of natural gas the premises will use over the next 12 months.
Changes in operating hours, production levels or gas equipment can affect future consumption, meaning historical usage may no longer accurately reflect your business's requirements.
New Gas Connections
Where no historical consumption data exists, EAC is estimated using the expected gas requirements of the premises. The calculation takes account of:
- Gas appliances: The number, type and rated gas input of boilers, cookers, fryers and other equipment.
- Operating hours: The expected number of hours each appliance will operate daily or weekly.
- Seasonal demand: Changes in gas consumption throughout the year, particularly for space heating.
- Annual operating days: The number of days the business operates each year.
For example, a gas appliance with a rated input of 50 kW operating for 8 hours per day over 250 days has a theoretical annual consumption of 100,000 kWh if it operates at full input throughout those hours. This calculation provides a starting estimate. Actual consumption will depend on appliance utilisation, operating conditions and seasonal demand.
Why Estimated Annual Consumption (EAC) Matters for Your Gas Bill
Estimated Annual Consumption (EAC) is an important factor in determining your business gas tariff classification and pricing structure. An accurate EAC matters for three reasons:
- Tariff classification: EAC is used alongside Supply Point Capacity (SPC), where applicable, to determine whether your business falls into the Small Business User (SBU), Medium Business User (MBU), Fuel Variation Tariff (FVT) or Daily Metered (DM) category.
- Gas price comparisons: An accurate annual consumption estimate allows suppliers to calculate more reliable quotations and projected annual costs.
- Changes in consumption: If your business has expanded, reduced production or installed more efficient equipment, your historical EAC may no longer reflect your current gas requirements.
Your actual gas consumption is billed using meter readings. EAC is an estimate used for tariff classification and pricing purposes, rather than a fixed quantity of gas you must purchase.
Supply Point Capacity (SPC) is a separate measurement that affects capacity-related charges for larger gas users. For more information, read our Business Gas SPC and EAC Explained guide.
Who Sets and Reviews Business Gas EAC in Ireland?
Gas Networks Ireland (GNI) is responsible for determining and reviewing Estimated Annual Consumption (EAC) for gas connections in Ireland.
For existing connections, EAC is calculated using historical meter readings and consumption data. For new connections, it is based on the estimated gas requirements of the premises.
Gas Networks Ireland reviews EAC annually, with revised figures taking effect from 1 October, the start of the Irish gas year. Your gas supplier uses the EAC provided by Gas Networks Ireland to determine your tariff classification and applicable pricing structure.
💡 Important: If your business has significantly changed its gas consumption, contact your supplier to check whether your EAC still reflects your current requirements.
What If Your Business Gas EAC Is Incorrect?
If your Estimated Annual Consumption (EAC) does not reflect your business's current gas usage, you can request a review through your gas supplier. Follow these steps:
- Check your EAC: Find the Estimated Annual Consumption (EAC) or Annual Quantity (AQ) recorded for your gas meter.
- Review actual consumption: Add up your gas consumption in kWh over the previous 12 months using your gas bills or meter readings.
- Identify any changes: Consider whether new equipment, changes in operating hours or business expansion have increased or reduced your gas requirements.
- Contact your supplier: If your EAC appears incorrect, ask your gas supplier to request a review with Gas Networks Ireland.
Gas Networks Ireland is responsible for assessing and updating EAC. Any revisions are subject to its review procedures. An accurate EAC helps your business remain on the appropriate gas tariff and allows suppliers to provide more reliable annual cost estimates.
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Frequently Asked Questions (FAQs)
Estimated Annual Consumption (EAC) is the estimated amount of natural gas a business will use over 12 months, measured in kilowatt-hours (kWh). Gas Networks Ireland uses historical consumption data or forecast usage to establish EAC, which helps determine the appropriate business gas tariff category.
There is no difference. Estimated Annual Consumption (EAC) and Annual Quantity (AQ) both refer to the estimated amount of natural gas a business is expected to consume over 12 months, measured in kilowatt-hours (kWh).
For existing gas connections, Gas Networks Ireland calculates EAC using historical meter readings and consumption data. For new connections without a consumption history, EAC is estimated using the gas appliances installed, their expected operating hours and seasonal demand.
EAC helps determine your business gas tariff classification and pricing structure. An inaccurate EAC can result in your business being placed in the wrong tariff category, potentially increasing your gas costs. Keeping your EAC up to date also helps suppliers provide accurate annual cost estimates.
Gas Networks Ireland is responsible for determining and reviewing Estimated Annual Consumption (EAC). It uses historical gas consumption data or forecast usage for new connections. EAC is reviewed annually, with updated figures taking effect from 1 October, the start of the Irish gas year.
Yes. If your EAC no longer reflects your actual gas consumption, you can ask your gas supplier to request a review with Gas Networks Ireland. Supporting information, such as recent meter readings, annual consumption figures or changes to gas equipment, can help support your request. Gas Networks Ireland will assess whether an adjustment is required.
Your EAC or Annual Quantity (AQ) may be displayed on your business gas bill. If it is not shown, contact your gas supplier to request the figure. You can then compare it with your actual gas consumption over the previous 12 months to check whether the estimate is accurate.
Gas Networks Ireland reviews Estimated Annual Consumption (EAC) annually using historical gas consumption data. Updated figures generally take effect from 1 October, the start of the Irish gas year. If your business's gas usage changes significantly during the year, you can ask your supplier to request an EAC review.
