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Senior / Principal Mechanical Design Engineer – Building Services

Location: South Wales | Salary: Competitive + Package

Job Type: Full-time, Permanent

Lead Mechanical Design, Mentor Talent, and Deliver High-Quality Projects

A well-established and highly respected Building Services Contractor in South Wales is seeking a Senior / Principal Mechanical Design Engineer to strengthen their in-house mechanical design team. With a strong pipeline of projects across commercial, education, healthcare, residential, hospitality, and retail sectors, this is an exciting opportunity to take a leadership role with real responsibility.

You’ll join a supportive team delivering technically challenging and rewarding projects, from multimillion-pound new builds to complex refurbishments, while having the chance to mentor junior engineers and shape the future of the department.

Key Responsibilities

Lead mechanical design on projects from concept through to completion

Attend and chair design and coordination meetings with internal and external teams

Act as the main point of contact for clients, representing the business professionally

Ensure all designs comply with UK building regulations, CIBSE guides, and industry standards

Develop detailed designs using software such as Hevacomp, IES, Revit, and AutoCAD

Review and oversee drawings, schematics, and specifications

Mentor and support junior engineers, apprentices, and wider design staff

Report project progress to the M&E Design Director

Collaborate with the in-house construction team and multidisciplinary stakeholders

What We’re Looking For

Degree or HNC/HND in Mechanical or Building Services Engineering (or similar)

Proven experience in mechanical building services design, ideally within a contractor or consultancy

Strong technical knowledge of HVAC, LTHW/CHW systems, and sustainable design principles

Competence with design software (Revit, IES, AutoCAD, Hevacomp)

Ability to lead projects, take ownership of delivery, and work within budgets

Good commercial awareness and client-facing skills

Experience in a contracting environment is advantageous, but training can be provided

Why Join?

Secure, long-term role with a company that invests in its people

Competitive salary and benefits package, negotiable depending on experience

Flexible working arrangements where required

Exposure to a wide range of technically challenging projects

Real autonomy and the opportunity to influence the growth of the design function

Supportive environment with clear progression opportunities

If you’re a Senior / Principal Mechanical Design Engineer looking to take the next step in your career or work on high-quality projects within a company that values its people, apply now or get in touch for a confidential conversation

If you are interested in applying for this job please press the Apply Button and follow the application process. Energy Jobline wishes you the very best of luck in your next career move.