H A O’Neil is Irelands largest and most experienced Mechanical HVAC and Process Piping Contractor, serving the construction industry for over 125 years.

We provide the following services throughout Ireland, UK, Europe and the Middle East.:

  • HVAC Installation
  • Process Pipework Installation
  • Plant and Tool Hook-Ups
  • Process Plant Erection
  • High Pressure Steam
  • Water Treatment
  • Refrigeration
  • Ventilation
  • Medical Gases
  • Specialist Rigging
  • Commissioning of Building Services
  • Maintenance of Building Services
  • Design
  • High Corrosion Installation
  • Air Conditioning
  • Heating
  • Plumbing
  • Gas Installation


Latest News

Company Announcement









We are delighted to announce the appointment of Robbie Irvin as Operations Director of Patrick Lynch Ltd, an Electrical Division of Jones Engineering Group


CIF #BuildingEquality Campaign

Meet Eileen Faherty, currently our Lead Electrical Quantity Surveyor and #TeamJones since 1998. Eileen started out with us as an Electrical Apprentice. In this...

Microsoft’s new €134m campus in Dublin

We’re proud to have worked on Microsoft’s new €134m campus in Dublin, One Microsoft Place.

“The building itself has 3,000 seats spread across open-plan floors...