| 1 | Purmo Group (UK) LTD | Ireland | Letterkenny | Glencar Shopping Centre | Donegal | F92 PCH9 | N/A | 2022 | $94,050,465 | 387 | N/A | N/A | 909807 |
| 2 | Gaffney Mechanical LIMITED | Ireland | Dublin | 1 Grants Row Lower Mount Street | Dublin | D02 HX96 | N/A | 2011 | $92,554,947 | 194 | N/A | N/A | 506525 |
| 3 | Vestas Ireland LIMITED | Ireland | Swords | Skybridge House | Dublin | K67 P6K2 | N/A | 2008 | $55,502,913 | 103 | N/A | N/A | 459005 |
| 4 | Dominic O'connor LIMITED | Ireland | Loughrea | Eastpoint Business Park | Galway | N/A | doconnor.***** | 2002 | $46,989,915 | 99 | N/A | N/A | 359850 |
| 5 | Ideal Energy Distribution LIMITED | Ireland | Malahide | Ascot House | Dublin | K36 HH42 | N/A | 2019 | $32,489,663 | 16 | N/A | N/A | 652026 |
| 6 | Crystal Air LIMITED | Ireland | Naas | Unit 3 Butterstream Business Park Co. Kildare | Kildare | W91 VK31 | crystalair.***** | 2014 | $31,360,900 | 123 | N/A | N/A | 547631 |
| 7 | Kerrigan Mechanical LIMITED | Ireland | Navan | Unit 2 Athboy Business Park | Meath | C15 W13H | lidl.***** | 1998 | $29,785,435 | 63 | N/A | N/A | 285629 |
| 8 | Mecpro Engineering LIMITED | Ireland | Dundalk | Derrycannagh | Louth | N/A | N/A | 2011 | $27,072,685 | 25 | N/A | N/A | 499042 |
| 9 | Automated Technical Controls LIMITED | Ireland | Dublin 24 | Atc House | Dublin | D24 EF99 | atc.***** | 1991 | $23,393,674 | 37 | N/A | N/A | 166907 |
| 10 | Sse Airtricity Energy Services LIMITED | Ireland | Dublin | South County Business Park | Dublin | N/A | N/A | 2009 | $20,238,226 | 31 | N/A | N/A | 476708 |
| 11 | T. Bourke & CO. LIMITED | Ireland | Blackrock | T22 Stillorgan Industrial Park | Dublin | A94 FX96 | tbourke.***** | 1972 | $19,126,934 | 80 | N/A | N/A | 39174 |
| 12 | Budget Energy LIMITED | Ireland | Dublin | Building 2, 3rd & 4th Floor, the Green, Dublin Airport Central | Dublin | K67 E2H3 | N/A | 2011 | $11,459,139 | 2 | N/A | N/A | 496678 |
| 13 | Lenmac Mechanical Services LIMITED | Ireland | Limerick | T/a Sensoryfm | Limerick | V94 3D71 | lenmacservices.***** | 1988 | $11,320,306 | 86 | N/A | N/A | 136082 |
| 14 | MR. Vent LIMITED | Ireland | Dublin 12 | Unit 5, Park West Drive | Dublin | D12 A720 | q-nis.***** | 2011 | $8,958,142 | 25 | N/A | N/A | 499705 |
| 15 | Cross Hire LIMITED | Ireland | Cork | Old Mallow Road | Cork | T23 XC60 | ireservices.***** | 2006 | $6,691,784 | 25 | N/A | N/A | 416031 |
| 16 | Mastertherm Heat Pumps LIMITED | Ireland | Dublin | Unit 46 | Dublin | N/A | N/A | 2017 | $5,388,729 | 2 | N/A | N/A | 605218 |
| 17 | Radco Distribution Ireland LIMITED | Ireland | Dublin 24 | Unit 1c Broomhill Business Complex Broomhill Road | Dublin | N/A | N/A | 2001 | $3,164,175 | 39 | N/A | N/A | 350204 |
| 18 | Laurence Mechanical Services LIMITED | Ireland | Cavan | Ballinagh Road | Cavan | H12 XE44 | N/A | 1992 | $3,164,175 | 33 | N/A | N/A | 190082 |
| 19 | Haus- Und Gebaeudetechnik LIMITED | Ireland | Dublin | Kandoy House 2 Fairview Strand | Dublin | D03Y1E2 | N/A | 2023 | $3,164,175 | 25 | N/A | N/A | 752760 |
| 20 | Viridus Energy LIMITED | Ireland | Ranelagh | 4 Manders Terrace | West Meath | N/A | N/A | 2023 | $3,164,175 | 25 | N/A | N/A | 735660 |
| 21 | Hydraulic Hose Services LIMITED | Ireland | Dublin | Pirtek Dublin | Dublin | D24HKF7 | pirtek.***** | 2006 | $2,391,993 | 12 | N/A | N/A | 421872 |
| 22 | A&B Mechanical Homes LIMITED | Ireland | Malahide | Block A Apartment 107 | Dublin | K36 FD80 | N/A | 2022 | $1,294,672 | 15 | N/A | N/A | 712346 |
| 23 | Heatgen Installations LIMITED | Ireland | Monaghan | Scotstown Business Centre | Monaghan | H18 R960 | N/A | 2024 | $885,969 | 7 | N/A | N/A | 767010 |
| 24 | Dmr Engineering LIMITED | Ireland | Dublin | Unit 21 (d3) Bymac Centre Northwest Business Park | Dublin | D15W027 | N/A | 2013 | $670,661 | 4 | N/A | N/A | 535182 |
| 25 | Ashgrove Engineering LIMITED | Ireland | Mallow | Ida Business & Technology Park | Cork | P51 HY51 | ashgrove.***** | 2001 | $632,835 | 100 | N/A | N/A | 409960 |
| 26 | Tim Kelly Mechanical LIMITED | Ireland | Ballinrobe | Claremorris Road | Mayo | F31 RW66 | timkellyengineering.***** | 1979 | $632,835 | 66 | N/A | N/A | 67961 |
| 27 | Rilta Environmental LIMITED | Ireland | Portlaoise | Enva Ireland | Laois | R32 XD95 | N/A | 2003 | $632,835 | 61 | N/A | N/A | 374837 |
| 28 | Ardrar Holdings LIMITED | Ireland | Dublin | 1 Warrington Place | Dublin | N/A | N/A | 2018 | $632,835 | 59 | N/A | N/A | 632290 |
| 29 | Alpha Mechanical Services LIMITED | Ireland | Dublin | Unit 8 Willsborough Business Centre | Dublin | D17 | N/A | 2013 | $632,835 | 57 | N/A | N/A | 534907 |
| 30 | Mcgrattan & Kenny LIMITED | Ireland | Dublin | North City Business Park | Dublin | D11 PH30 | mcgk.***** | 1968 | $632,835 | 56 | N/A | N/A | 26508 |
| 31 | Riverside Mechanical LIMITED | Ireland | Dublin | Unit A6 Centrepoint | Dublin | D11 Y727 | riverside-mechanical.***** | 2005 | $632,835 | 49 | N/A | N/A | 397896 |
| 32 | Kcmg Engineering LIMITED | Ireland | Naas | 10 Glen Easton Grove | Kildare | W23 DK72 | N/A | 2017 | $632,835 | 44 | N/A | N/A | 610069 |
| 33 | Kingmek LIMITED | Ireland | Gormanstown | Irishtown | North Tipperary | N/A | N/A | 2003 | $632,835 | 39 | N/A | N/A | 373827 |
| 34 | Architectural Steel & Mechanical Services LIMITED | Ireland | Cork | Waterfront Apartments | Cork | T45 FT28 | N/A | 2006 | $632,835 | 39 | N/A | N/A | 413884 |
| 35 | Lowflo LIMITED | Ireland | Dublin | Unit 4 Colberts Fort Business Park | Dublin | D24 PD29 | lowflo.***** | 2013 | $632,835 | 35 | N/A | N/A | 535360 |
| 36 | Walsh Mechanical Engineering LIMITED | Ireland | Ballinrobe | Kilmaine Road | Mayo | F31 R299 | wme.***** | 1986 | $632,835 | 31 | N/A | N/A | 105639 |
| 37 | G. M. G. Mechanical Services LIMITED | Ireland | Donegal | Lacklum | Donegal | N/A | gmg.***** | 1998 | $632,835 | 29 | N/A | N/A | 295340 |
| 38 | Walsh & Sheehan LIMITED | Ireland | Waterford | Unit 25 West Side Business Park | Waterford | N/A | walshandsheehan.***** | 2005 | $632,835 | 29 | N/A | N/A | 412794 |
| 39 | D. Harris (heating And Plumbing) LIMITED | Ireland | Dublin | Unit 11a Santry Business Park | Dublin | D09 T9C4 | harrisheating.***** | 1981 | $632,835 | 29 | N/A | N/A | 82051 |
| 40 | Feakle Gas And Plumbing LIMITED | Ireland | Feakle | Derrynaneal | Limerick | V94 2X89 | N/A | 2017 | $632,835 | 28 | N/A | N/A | 604804 |
| 41 | Learnd Ireland Services LIMITED | Ireland | Dublin | Bracetown Business Park | Dublin | DUBLIN | N/A | 2019 | $632,835 | 26 | N/A | N/A | 657407 |
| 42 | Clare Drains Environmental LIMITED | Ireland | Ennis | Unit 10 Quin Road Business Park | Clare | V95 VW74 | claredrains.***** | 2011 | $632,835 | 25 | N/A | N/A | 495366 |
| 43 | Alert Mechanical LIMITED | Ireland | Dundalk | Stephenstown | Louth | A91 VXE2 | N/A | 2007 | $632,835 | 25 | N/A | N/A | 449298 |
| 44 | Kibo Ireland LIMITED | Ireland | Tullamore | Clara Road | Offaly | N/A | autelco.***** | 2003 | $632,835 | 23 | N/A | N/A | 369341 |
| 45 | Navio LIMITED | Ireland | Dublin | Cube House Unit 1 | Dublin | D15 NYH4 | N/A | 2020 | $632,835 | 22 | N/A | N/A | 681041 |
| 46 | Lacey's Plumbing And Heating Supplies LIMITED | Ireland | Dublin 11 | 118 Millennium Trade Park | Dublin | D11WK12 | laceys.***** | 2015 | $632,835 | 21 | N/A | N/A | 559751 |
| 47 | Killarney Mechanical Services LIMITED | Ireland | Killarney | Meanus | Kerry | V93 C6H2 | kmsservices.***** | 1996 | $632,835 | 20 | N/A | N/A | 250720 |
| 48 | Rel Cooling Services LIMITED | Ireland | Carlow | Carlow Enterprise Centre | Carlow | N/A | rel.***** | 2012 | $632,835 | 18 | N/A | N/A | 515495 |
| 49 | Bartech Engineering LIMITED | Ireland | Dublin 11 | 278 Glasnevin Avenue | Dublin | D11PW2T | N/A | 2014 | $632,835 | 17 | N/A | N/A | 545947 |
| 50 | Kearney & Phelan Engineering LIMITED | Ireland | Castlecomer | 51 the Acorns Upper | Kilkenny | N/A | N/A | 2012 | $632,835 | 17 | N/A | N/A | 513398 |