Senior Project Engineer – Mechanical U.K (Data Centre Retrofit)

About Ethos

Ethos is a collaborative team of engineers, consultants, and creative thinkers designing and delivering data centre and energy infrastructure across the world's most dynamic markets. As a multidisciplinary consultancy, we combine technical expertise, creativity, and integrated delivery to lead complex, mission-critical projects.

Built on strong relationships, clear leadership, and a can-do mindset, Ethos is entering an exciting phase of growth, expanding our capabilities and taking on increasingly high-impact projects across EMEA and beyond.

Sustainability guides how we design, collaborate, and deliver, creating innovative solutions and lasting value for our clients and communities — making Performance Made Possible.

About the Job

As a Senior Project Engineer – Mechanical, you will play a key role within Ethos’ Data Centre team, with a focus on retrofit projects across mission-critical data centre environments.

You will lead the design, specification and delivery of mechanical systems, ensuring projects are delivered safely, efficiently and to the highest technical standards. Working within live environments, you will help maintain continuity of operations while delivering high-quality engineering solutions.

This role will also involve managing project delivery, mentoring junior engineers and acting as a key technical point of contact for clients and contractors across major European data centre markets.

Responsibilities:

• Lead the design and delivery of mechanical building services upgrades within live data centre environments, including M&E upgrades, capacity increases, technology refreshes, phased refurbishments, and lifecycle replacements.

• Develop and manage retrofit-specific design strategies, including tie-ins to live systems, redundancy planning, outage and staging strategies, and resilience design.

• Conduct or oversee technical due diligence of existing data centre facilities, including capacity unlock assessments (power, cooling, and white space).

• Prepare and review detailed design drawings, schematics, schedules, technical reports, and tender documentation.

• Manage project scope, budget, programme, and contracts — identifying and mitigating scope creep, risks, and live-environment constraints.

• Liaise directly with clients (hyperscale, colocation, and enterprise operators), contractors, and vendors to ensure project goals are achieved with zero operational disruption.

• Drive quality assurance and governance across all assigned projects, adhering to WAP/PTW protocols in live environments.

• Mentor and support the development of junior engineers and graduate staff within the retrofit workstream.

• Support business development by contributing to proposals, client presentations, and technical strategies for retrofit opportunities across EMEA.

• Champion innovation in live-environment engineering and contribute to the continuous improvement of Ethos’ retrofit delivery model.

• Lead phasing strategy for live cooling and HVAC upgrades, ensuring continuity of critical mechanical infrastructure throughout delivery.

About You

Experience & Qualifications

• Bachelor’s or Master’s degree in Mechanical Engineering or a related discipline.

• Minimum 8 years’ experience in building services engineering, with at least 3 years focused on data centre or mission-critical projects.

• Demonstrable experience working in live, operational data centre environments — including brownfield upgrades, M&E replacements, or phased refurbishments.

• Chartered Engineer status (or actively working towards Chartership) with Engineers Ireland or equivalent.

• Proven track record managing multi-million-euro MEP projects from concept to completion.

• Strong understanding of Irish and EU building regulations; knowledge of LEED/BREEAM and the EU Energy Efficiency Directive is an advantage.

Technical Skills

• Strong expertise in mechanical systems design for live data centre environments, including chilled water plant, CRAC/CRAH upgrades, air handling units, in-row cooling, and fire suppression systems.

• Experience delivering M&E upgrades within operational facilities — including tie-ins to live plant, outage management, and resilience planning.

• Proficient in AutoCAD, Revit MEP, Bluebeam, and Microsoft Office; working knowledge of IES, HAP, or similar mechanical analysis tools is advantageous.

• Strong knowledge of CIBSE, ASHRAE, BS, IS, and EN standards applied in retrofit and live-environment contexts.

• Understanding of PUE optimisation and cooling efficiency improvements to meet EU Energy Efficiency Directive targets and client ESG requirements.

• Familiarity with commissioning and integration of mechanical systems within live, mission-critical facilities.

Soft Skills

• Excellent communication and presentation skills, with confidence in client-facing settings.

• Strong organisational and problem-solving abilities, capable of managing multiple concurrent retrofit projects.

• Collaborative approach to working across multidisciplinary teams including mechanical, electrical, sustainability, and BIM disciplines.

• Proactive, detail-oriented mindset with a sharp focus on risk management and technical quality in live environments.

• Calm under pressure — able to make sound engineering decisions within constrained, operational environments.

Why Join Us?

• Join collaborative leaders – Work alongside experienced, approachable professionals who

  combine technical excellence with calm, supportive leadership.

• Make a real impact – Contribute to mission-critical infrastructure projects that support the digital and energy transition across EMEA and beyond.

• Grow with us – As a rapidly growing consultancy, we offer opportunities to develop your skills, broaden your experience, and build your career.

• Shape a more sustainable future – Sustainability isn't an initiative—it's embedded in every project, every discipline, and every decision we make.

We offer:

• Flexible Fridays and a 9-day fortnight working schedule — enjoy every second Friday off to maintain work–life balance.

• A culture that values flexibility, learning, and teamwork, with clear progression pathways and support toward professional accreditation.

• Opportunities to work alongside some of the most experienced engineers in the industry, within a forward-thinking, technology-driven consultancy.

Benefits:

• Flexible working times

• 25 Days holidays

• Pension Scheme

• Refer a Friend scheme

• Subsidised Health Insurance Allowance

• Working travel out-of-pocket expenses

• Regular training/mentoring / further college support

• Support for Chartership

• A Professional Subscription Fee paid by the company

• Paid Statutory Leaves

• Heavily subsidised social committee