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Industry Insights 8 min read

Accelerated Capital Allowance: The Tax Relief Irish SMEs Are Missing

The Accelerated Capital Allowance lets Irish businesses write off 100% of qualifying energy-efficient equipment costs against tax in year one. Here's how it works, with worked examples.

By Optim Energy Team

There’s a tax relief available to every Irish business that invests in energy-efficient equipment. It provides a 100% write-off in year one instead of the standard eight-year depreciation. It can be combined with SEAI grants. And most Irish SMEs have never heard of it.

It’s called the Accelerated Capital Allowance (ACA), and it’s one of the most underused financial incentives in Irish business.

The Quick Version

  • The ACA lets you write off 100% of qualifying energy-efficient equipment against tax in the year of purchase
  • Standard capital allowances spread the write-off over 8 years (12.5% per year)
  • At 25% corporation tax, a €20,000 investment generates a €5,000 tax saving in year one (vs €625/year over 8 years normally)
  • Can be combined with SEAI grants — they stack
  • No prior approval needed — claimed through your tax return
  • Equipment must be on Revenue’s qualifying list

How Normal Capital Allowances Work

When a business buys equipment (plant and machinery), the cost is written off against taxable profits over eight years at 12.5% per year. This is the standard “wear and tear” capital allowance.

Example — standard treatment:

  • Equipment cost: €20,000
  • Annual write-off: €2,500 (12.5% × €20,000)
  • Tax saving per year (at 25% corporation tax): €625
  • Total tax saving over 8 years: €5,000

The total tax saving is the same either way — but with standard allowances, you wait 8 years to get it all.


How the ACA Changes the Maths

The Accelerated Capital Allowance lets you write off 100% of the cost in year one.

Example — with ACA:

  • Equipment cost: €20,000
  • Year-one write-off: €20,000 (100%)
  • Tax saving in year one (at 25%): €5,000
  • Waiting period: none

Same equipment, same total relief — but you get the entire tax benefit immediately. For cash flow, this is significant. That €5,000 is available to fund other improvements, reduce borrowing, or simply improve your working capital position.


Worked Examples

Example 1: LED Lighting Upgrade

A retail shop replaces old fluorescent lighting with LED fittings and intelligent controls.

ItemAmount
LED lighting system cost€12,000
SEAI SEUS grant (40%)-€4,800
Net cost to business€7,200
ACA tax saving (25% × €7,200)-€1,800
Effective cost€5,400
Annual energy saving€3,200
Effective payback1.7 years

Without ACA and grants, the payback would be 3.75 years. The combination of SEUS grant + ACA cuts it to under 2 years.

Example 2: Heating Controls Upgrade

An office installs a modern building energy management system (BEMS), such as the Optim EOS, with weather compensation and zone control.

ItemAmount
BEMS installation cost€8,000
SEAI SEUS grant (35%)-€2,800
Net cost to business€5,200
ACA tax saving (25% × €5,200)-€1,300
Effective cost€3,900
Annual energy saving€2,800
Effective payback1.4 years

Example 3: Hotel Heat Pump Installation

A guesthouse replaces an oil boiler with an air-source heat pump for heating and hot water.

ItemAmount
Heat pump system cost€35,000
SEAI SEUS grant (40%)-€14,000
Net cost to business€21,000
ACA tax saving (25% × €21,000)-€5,250
Effective cost€15,750
Annual energy saving€8,500
Effective payback1.9 years

Plus the annual saving increases as carbon tax on oil rises through to 2030. The heat pump gets more cost-effective every year.


What Equipment Qualifies

Equipment must be listed on Revenue’s qualifying energy-efficient equipment list, which covers these categories:

Qualifying categories

  • Lighting — LED luminaires, lighting controls, occupancy sensors, daylight dimming systems
  • Motors and drives — high-efficiency motors, variable speed drives
  • Heating and cooling — heat pumps, high-efficiency boilers, heating controls, weather compensation
  • Building energy management systems — BEMS, zone controls, energy monitoring equipment
  • Refrigeration — high-efficiency display cases, compressors, controllers
  • ICT equipment — energy-efficient servers, power management systems
  • Electrical and electronic — power factor correction, UPS systems

How to check

Revenue maintains the list of qualifying products and publishes it online. Products must meet specific energy performance criteria to be included. Before purchasing, verify that the specific product or product category is on the current list.

Your energy auditor can help. When we produce an audit report, we flag which recommended measures involve ACA-qualifying equipment. This makes it straightforward for your accountant.


Combining ACA with SEAI Grants

The ACA and SEAI grants are complementary:

  • SEAI grants reduce the capital cost of the project (you receive cash back)
  • ACA reduces your tax bill based on your remaining expenditure

They can be used together because the ACA is a tax relief, not a grant. The key rule: you claim the ACA on your net expenditure after deducting any grants received.

The stacking benefit

Without supportWith SEAI grant onlyWith ACA onlyWith both
Full cost50-70% of cost~75% of cost~45-55% of cost

For a business paying 25% corporation tax and receiving a 40% SEAI grant, the combination reduces the effective cost to approximately 45% of the original price.


Who Benefits Most

The ACA is most valuable for:

  • Profitable businesses paying corporation tax or income tax — the tax saving is immediate
  • Businesses planning equipment replacements — buying energy-efficient replacements qualifies for ACA even if the purchase was already planned
  • Businesses doing multiple measures — ACA applies to each qualifying item, so a comprehensive upgrade benefits significantly
  • Sole traders on high marginal tax rates — at 40% income tax + USC, the effective saving per euro of qualifying expenditure is even higher than for companies

How to Claim

The process is straightforward:

  1. Purchase qualifying equipment — ensure it’s on Revenue’s current list
  2. Keep documentation — purchase invoice, equipment specification, energy audit report (if applicable)
  3. Inform your accountant — they need to know the expenditure qualifies for ACA treatment
  4. Claim on your tax return — CT1 (companies) or Form 11 (sole traders), in the capital allowances section
  5. No prior approval needed — it’s a self-assessment claim, like any other capital allowance

Common pitfall: Accountants who aren’t aware of the ACA will apply the standard 12.5% rate automatically. If you’re investing in energy-efficient equipment, tell your accountant about the ACA before they file your return.


The Accountant Conversation

If your accountant hasn’t dealt with the ACA before, here’s what they need to know:

  • Legislation: Taxes Consolidation Act 1997, Section 285A
  • Relief: 100% first-year capital allowance for qualifying energy-efficient equipment
  • Qualifying list: Published by Revenue, updated periodically
  • Claiming: Through capital allowances section of CT1/Form 11
  • Interaction with grants: Claim on net expenditure after deducting grant income
  • Evidence: Purchase invoice + equipment specification showing it’s on the qualifying list

Most accountants, once they understand the relief, will look for it in future years too. It’s a straightforward claim once you know it exists.


Next Steps

  1. Book a commercial energy audit — we’ll identify which equipment in our recommendations qualifies for ACA
  2. Check the qualifying list on revenue.ie before making any equipment purchase
  3. Talk to your accountant about ACA before your next tax filing
  4. Read the SEAI grants guide to understand how grants and ACA work together
  5. Review your energy costs to understand the savings opportunity

The ACA exists to encourage businesses to choose energy-efficient equipment. If you’re going to invest in equipment anyway, choosing a qualifying product costs you nothing extra — and the accelerated tax relief improves your cash flow significantly.


The Accelerated Capital Allowance is one of the simplest and most underused financial incentives for Irish businesses. If you buy qualifying energy-efficient equipment, you get 100% tax relief in year one instead of waiting eight years. Combined with SEAI grants, the effective cost of energy upgrades becomes remarkably manageable.