Senior Mechanical Engineer, HVAC

As a Senior Mechanical Engineer at Giga, you will own HVAC and mechanical system design for AI data center infrastructure from early concept through construction documents. That means load calculations, equipment selections, hydronic system modeling, ductwork and piping sizing — the full scope. You won’t be reviewing someone else’s work; you’ll be producing it. If you’re the kind of engineer who wants to see your designs actually get built — and built fast — this is the role.

This role is based out of one of our offices (San Francisco, CA / Long Beach, CA / Houston, TX). We work in person because the best engineering happens when smart people are in the same room.

• Lead detailed HVAC mechanical design for mission-critical data center facilities, from schematic design through construction documents

• Perform load calculations, psychrometric analysis, ductwork sizing, piping sizing, and equipment selections

• Model and analyze hydronic systems using Pipe Flo or equivalent software

• Develop system models and energy analyses using Trane Trace, Carrier HAP, or similar tools

• Produce design documentation in AutoCAD and Revit MEP, maintaining coordination-ready models throughout design phases

• Apply ICC/UPC codes and applicable ASHRAE standards to ensure compliant, optimized designs

• Collaborate with other disciplines to integrate mechanical systems into the broader facility design

• Interface with equipment vendors and contractors to validate selections and support procurement

• Support construction administration, RFI responses, and submittal reviews

• Bachelor’s degree in Mechanical Engineering

• 5+ years of professional HVAC design experience

• Proficiency in AutoCAD and Revit MEP for system design and modeling

• Proficiency in Trane Trace, Carrier HAP, or similar load calculation software

• Proficiency in Pipe Flo or similar hydronic system modeling software

• Strong working knowledge of ICC/UPC codes and ASHRAE standards (62.1, 90.1, 90.4, and related)

• Demonstrated competence in load calculations, psychrometrics, piping and ductwork sizing, and equipment selection

• Knowledge of mechanical cooling topologies used in data centers: CRAC/CRAH units, chilled water plants, air-cooled chillers, water-side and air-side economization, and evaporative/adiabatic cooling

• Familiarity with high-density and liquid cooling approaches (direct liquid cooling, rear-door heat exchangers, immersion cooling)

• Experience with hydronic system design including primary/secondary loops, variable flow systems, and plant sequencing

• Experience reviewing or performing CFD analysis for airflow and thermal modeling

• Understanding of how mechanical systems integrate with electrical infrastructure (UPS, generators, switch gear)

• Commissioning experience — FAT, SAT, or functional performance testing

• Professional Engineer (PE) license, or actively pursuing licensure

• Experience authoring design narratives and basis-of-design documents and presenting them to clients or stakeholders

• Subsidized health, dental, and vision insurance

• Equity (options) in a rapidly growing startup

• 401(k) with 4% employer match

• Unlimited PTO

• Parental leave

• Healthcare and Dependent Care Flexible Spending Accounts (FSA) or Health Savings Account (HSA)

• Commuter benefits