Senior Mechanical Engineer, HVAC

What You’ll Do 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. Where you’ll work 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. Responsibilities Lead detailed HVAC mechanical design for mission-critical data center facilities, from schematic design through construction documentsPerform load calculations, psychrometric analysis, ductwork sizing, piping sizing, and equipment selectionsModel and analyze hydronic systems using PipeFlo or equivalent softwareDevelop system models and energy analyses using Trane Trace, Carrier HAP, or similar toolsProduce design documentation in AutoCAD and Revit MEP, maintaining coordination-ready models throughout design phasesApply ICC/UPC codes and applicable ASHRAE standards to ensure compliant, optimized designsCollaborate with other disciplines to integrate mechanical systems into the broader facility designInterface with equipment vendors and contractors to validate selections and support procurementSupport construction administration, RFI responses, and submittal reviews Requirements Bachelor’s degree in Mechanical Engineering5+ years of professional HVAC design experienceProficiency in AutoCAD and Revit MEP for system design and modelingProficiency in Trane Trace, Carrier HAP, or similar load calculation softwareProficiency in PipeFlo or similar hydronic system modeling softwareStrong 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 Bonus Points 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 coolingFamiliarity 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 sequencingExperience reviewing or performing CFD analysis for airflow and thermal modelingUnderstanding of how mechanical systems integrate with electrical infrastructure (UPS, generators, switchgear)Commissioning experience — FAT, SAT, or functional performance testing Bonus Points Professional Engineer (PE) license, or actively pursuing licensureExperience authoring design narratives and basis-of-design documents and presenting them to clients or stakeholders Benefits Subsidized health, dental, and vision insuranceEquity (options) in a rapidly growing startup401(k) with 4% employer matchUnlimited PTOParental leaveHealthcare and Dependent Care Flexible Spending Accounts (FSA) or Health Savings Account (HSA)Commuter benefits