The Building Types Costing Irish Businesses the Most
A BER rating gives your building a letter grade. It doesn’t tell you what that grade actually costs you. Primary energy use does. It’s the real number behind the letter, measured in kilowatt hours per square metre per year, and it’s what your energy bill is really built on.
Every commercial building in Ireland gets a BER certificate when it’s built, sold or leased out. That certificate records exactly how much energy the building uses per square metre, based on its insulation, heating, and others.
Stack thousands of these certificates together by county and building type, and you get a real, measurable picture of how efficient Ireland’s business buildings actually are, not a guess.
Small and medium business electricity rates averaged around 24.27 cents per kWh in the first half of 2025. The typical Irish small business burns through 15,000 to 25,000 kWh a year.
So, we decided to find out where in Ireland that gap is worst. We looked at 83,380 non-domestic BER certificates from the CSO. That covers all 26 counties and 13 types of buildings, including offices, shops, warehouses, hotels, schools and hospitals, checked between 2009 and 2025.
These are the building types costing businesses the most
1. Roscommon
Roscommon tops the list. Shops are the reason why. Retail buildings in Roscommon average 1,725 kWh per square metre a year, against a national retail average of 871, backed by an estimated 298 certificates. Retail is already one of the most energy-hungry building types in the country nationally. Roscommon’s shops use nearly twice that amount. Local business owners are quietly paying for it every month.
2. Sligo
Sligo is the rare case where the problem isn’t one building type; it’s two. It ranks second worst in the country, and if you run a warehouse or an office here, the odds are stacked against you twice over. Sligo’s warehouses average 813 kWh per square metre a year, against a national warehouse average of just 418, nearly double. Its offices average 701 kWh per square metre a year, 75% higher than the national office average of 401.
3. Carlow
Retail is a big problem for Carlow businesses. Shops here use 1,157 kWh per square metre a year, 33% more than the national shop average. For shop owners on Carlow’s high streets, this isn’t just a stat. It shows up as a real cost on the energy bill every month.
4. Waterford
Shops are the main problem for Waterford businesses, just as in Roscommon and Carlow. Waterford’s shops use 1,138 kWh per square metre a year, well above the national shop average of 871, backed by around 791 certificates across the city and county combined. It’s also the main reason Waterford ranks fourth worst in the country overall.
5. Wexford
Community and day centres are costing Wexford businesses the most. These buildings use 932 kWh per square metre a year, more than double the national average of 407 for that building type, the widest gap of any building type in any county in the whole study.
Who else ranks in the top 10…
Offices are the biggest cost in two of these counties, Longford and Mayo. Offices in Longford average 580 kWh per square metre a year, 45% above the national office average, backed by around 152 certificates, and are the main reason Longford ranks 6th overall. Offices in Mayo average 573 kWh per square metre a year, 43% above average, backed by around 496 certificates, one of the biggest office samples in this whole report, and drive Mayo to 7th place overall.
From here down, three counties show a mix of building types pushing the number up, not just one. Limerick ranks 8th overall. Offices average 594 kWh per square metre a year, and warehouses average 619 kWh per square metre a year, both 48% above their national averages, backed by strong samples of around 856 and 433 certificates. Laois ranks 9th overall, driven mainly by offices, which average 536 kWh per square metre a year, 34% above average, backed by around 234 certificates. Donegal rounds out the top ten in 10th place. Warehouses average 577 kWh per square metre a year, 38% above average, and offices average 542 kWh per square metre a year, 35% above average, backed by around 255 and 506 certificates.
The pattern behind the numbers
Retail is the real villain in three of Ireland’s five worst counties. Roscommon, Carlow, and Waterford. Retail is already one of the most energy-hungry building types in the country, only beaten by Sports Facilities and Restaurants and Pubs, and it leaves Offices in the dust. Counties with older, standalone shops feel this problem the hardest.
But that’s not all…
Offices become the main driver in three of the next five counties. Longford, Mayo, and Laois. They also play a part in two more counties, Limerick and Donegal. But old office buildings are quietly running up the bill for everyone else just below them.
And the counties keeping a lid on it
At the other end of the table, Dublin has the lowest overall energy intensity of any county at 464 kWh/m² a year, 14% below the national average. A large, modern commercial building stock built up over decades of development helps keep that number down. Offaly (515), Cork (530), Wicklow (525) and Meath (526) round out the five most efficient counties, all comfortably below the national average of 542 kWh/m² a year.
What this means for your business
You can’t always change the building you operate from. But you can make sure you’re not overpaying for the energy it uses. That’s exactly what Procure.ie does. We work with over 25,000 businesses across Ireland, comparing suppliers and negotiating the lowest rates on business electricity and business gas, so you never pay more than you have to, whatever your building’s energy profile looks like.
Wherever your county ranks, Procure.ie can help make sure your energy bill doesn’t reflect the worst of it.
Methodology
We analysed 83,380 non-domestic BER audits published by the Central Statistics Office (CSO), covering average primary energy use by building type and county across all 26 counties and 13 non-domestic building types. This includes offices, retail units, warehouses, hotels, restaurants and pubs, schools, hospitals, and more, assessed between 2009 and 2025.
The figure of 83,380 is the total number of certificates recorded in the CSO’s Non-Domestic Building Energy Ratings release for Q4 2025, and it is confirmed two ways in that release: it is the sum of every county’s certificate total, and separately the sum of every building type’s certificate total, with both totals matching exactly.
