Senior Mechanical Engineer, HVAC

About Giga Giga is building gigawatts of AI data centers to hasten a future of intelligence and abundance. We build data centers fast and at scale by combining the capabilities of an equipment supplier, engineering firm, general contractor, and real estate developer under one roof. Our team moves quickly and thinks practically. If you're ready to make an impact in an industry that matters, we're looking for people like you. Why join Giga The Pace: We're building at a speed most companies talk about but never actually operate at. If you've been bored somewhere else, you won't be here. The Impact : Every person at Giga touches the work that matters. No layers, no waiting for approval chains. You'll see your fingerprints on what we ship. The Team: A team of operators defining the future of AI infrastructure. We recruit A-players from the most innovative companies in the world, and they choose Giga because the work here means more. The Moment : AI doesn't run without power, and that's us. Giga is the picks and shovels behind the AI revolution. This industry is about to explode, and you'll be in the room where it's already happening. 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 documents Perform load calculations, psychrometric analysis, ductwork sizing, piping sizing, and equipment selections Model and analyze hydronic systems using PipeFlo 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 Requirements 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 PipeFlo 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 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 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, switchgear) Commissioning experience — FAT, SAT, or functional performance te…