Mechanical Engineer III

Work with Us. Change the World.

At AECOM, we're delivering a better world. Whether improving your commute, keeping the lights on, providing access to clean water, or transforming skylines, our work helps people and communities thrive. We are the world's trusted infrastructure consulting firm, partnering with clients to solve the world’s most complex challenges and build legacies for future generations.

There has never been a better time to be at AECOM. With accelerating infrastructure investment worldwide, our services are in great demand. We invite you to bring your bold ideas and big dreams and become part of a global team of over 50,000 planners, designers, engineers, scientists, digital innovators, program and construction managers and other professionals delivering projects that create a positive and tangible impact around the world.

We're one global team driven by our common purpose to deliver a better world. Join us.

AECOM is seeking a Mechanical Engineer III to be based in our Atlanta, GA office. The Mechanical Engineer III will work independently with limited supervision to complete small and large project HVAC design requirements.

The Mechanical Engineer III will be responsible for the following items:

• Performs specific and moderate portions of a broader assignment of an experienced engineer.
• Gathers and correlates basic engineering data using established and well-defined procedures.
• Works on detailed or routine engineering assignments involving calculations and relatively simple tests.
• Proposes approach to solve new problems encountered using modifications of standard procedures or methods developed in previous assignments.
• Identifies discrepancies in results.
• Provides guidance to entry-level engineers.
• Performs work adhering to the agreed-upon budget and schedule with little supervision.
• Independently performs all the tasks necessary to complete primary design elements for engineering works.
• Performance at this level requires developmental experience in a professional position.
• Develop all aspects of heating, ventilation, and air conditioning systems design for government and commercial buildings.
• Use commercially available engineering software used in HVAC systems design.
• Evaluate, select, and apply standard engineering techniques, procedures, and judgement based on experience to design HVAC systems in buildings.
• Concisely express complex system solutions in very early design phases.
• Coordinate HVAC systems with other disciplines.
• Perform site/field visits to ascertain existing conditions including equipment condition evaluations.
• Make design decisions and recommendations with little input from senior staff.
• Review and approve shop drawings, respond to RFI’s, and other construction admin-related tasks.
• Organize and plan projects to ensure quality controls and project criteria are met and within budget.
• Perform self-check of work products before submitting to others.
• Maintain accurate project documentation and design data for permanent project files.
• Attend project meetings, both internal and with clients.
• Assist with mentoring of junior staff.

AECOM’s Buildings + Places practice includes architecture, interiors, building engineering, workplace strategy, business transformation, asset advisory, economics and development planning, master planning, urban planning, and landscape architecture. With a range of expertise from strategy and design through project realization, we create better outcomes to grow economies, protect natural systems, conserve natural resources, make societies more equitable, and connect and engage people through innovative, sustainable design solutions. Our teams have worked on signature projects such as air traffic control towers, NASA Laboratory buildings, and many others.

Minimum Requirements

• BA/BS in Mechanical Engineering plus four (4) years of relevant experience in mechanical design of HVAC systems for buildings , or demonstrated equivalency of experience and/or education.
• Due to nature of work/clients US Citizenship is required.
• AutoCAD and Revit experience.
• Experience in building HVAC load calculations and energy modeling.
• Experience with Microsoft Office suite.

Preferred Qualifications

• Six (6) years of professional experience designing HVAC and Plumbing systems utilizing industry-standard software.
• IES HVAC load modeling.
• Understanding of and ability to complete and coordinate project design assignments with the ability to review team member’s work for quality.
• Knowledge/experience with building HVAC systems design including but not limited to chilled water, hot water, condenser water, steam, and air-side systems.
• Knowledge/experience with building plumbing systems design including but not limited to sanitary drainage and venting, domestic service water, domestic hot water, and storm drainage systems.
• Experience with sustainable design and energy efficiency.
• Experience with ASHRAE & NFPA standards.
• Experience with International Building Codes.
• Ability to work on multiple projects simultaneously.
• Good interpersonal, organizational, verbal, and written communication skills.
• Good time management skills.
• Candidate should be well organized, able to demonstrate critical thinking, quickly recognize issues, and be part of the solution.

• Relocation assistance is not available.
• Sponsorship for US Employment Authorization is not available now or in the future for this position.

At AECOM, we are committed to maintaining a secure and trustworthy recruitment process and take any fraudulent hiring activity seriously. To support this commitment, all newly hired employees are required to attend an in-person Day 1 onboarding at an AECOM office location as a condition of employment.

About AECOM

AECOM is proud to offer comprehensive benefits to meet the diverse needs of our employees. Depending on your employment status, AECOM benefits may include medical, dental, vision, life, AD&D, disability benefits, paid time off, leaves of absences, voluntary benefits, perks, flexible work options, well-being resources, employee assistance program, business travel insurance, service recognition awards, retirement savings plan, and employee stock purchase plan.

AECOM is the global infrastructure leader, committed to delivering a better world. As a trusted professional services firm powered by deep technical abilities, we solve our clients’ complex challenges in water, environment, energy, transportation and buildings. Our teams partner with public- and private-sector clients to create innovative, sustainable and resilient solutions throughout the project lifecycle - from advisory, planning, design and engineering to program and construction management. AECOM is a Fortune 500 firm that had revenue of $16.1 billion in fiscal year 2025. Learn more at aecom.com.

What makes AECOM a great place to work

You will be part of a global team that champions your growth and career ambitions. Work on groundbreaking projects - both in your local community and on a global scale - that are transforming our industry and shaping the future. With cutting-edge technology and a network of experts, you’ll have the resources to make a real impact. Our award-winning training and development programs are designed to expand your technical expertise and leadership skills, helping you build the career you’ve always envisioned. Here, you’ll find a welcoming workplace built on respect, collaboration and community-where you have the freedom to grow in a world of opportunity.

As an Equal Opportunity Employer, we believe in your potential and are here to help you achieve it. All your information will be kept confidential according to EEO guidelines.