ONeil Engineering Services is a Virginia based Federally Certified Veteran Owned Small Business engineering design and consulting firm.  We offer services in Mechanical, Plumbing, Gas Piping and Electrical Engineering consultation and design.  OES provides design services on a wide range of projects in commercial construction including tenant up-fits, restaurants, multi-family residential developments, and commercial office buildings.  We specialize in renovations and adaptive reuse of historical sites.  ONeil Engineering Services' experienced engineers work closely with our clients to gain a thorough understanding of the scope and objectives for their proposed project.  This collaborative approach allows our engineers to provide the most comprehensive and cost effective proposal to align with every client's scope, schedule, and budget.  


ONeil Engineering Services provides our clients with creative and innovative designs for every individual project.  Our engineers possess the talent and expertise to produce solutions for the most complex design issues.  We work collaboratively with our clients from the early design phase through construction administration to ensure successful delivery of every project.

OES offers HVAC building load and energy analysis, 3D coordination drawings for use in BIM coordination drawings, and the evaluation of existing building mechanical systems.

OES offers advanced power systems services including short circuit studies, protective device coordination studies, arc flash hazard analysis, and power systems reliability analysis.  Our staff has significant experience in mission critical applications and data center environments for both design and commissioning.  ONeil Engineering Services has established a reputation for innovative design that consistently exceeds our clients expectations.

OES also can provide 3rd party inspections for MEP installations.


It is our mission to provide our clients with with personalized engineering design that is innovative and sustainable. 



ONeil Engineering Services supports and maintains memberships in:

American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

American Society of Plumbing Engineers (ASPE)

7x24 Exchange International

National Fire Protection Association (NFPA)

US Green Building Council (USGBC)


541330 Engineering Services

541618 Utilities Management Consulting Services