Lead HVAC Mechanical Engineer

Lead HVAC Mechanical Engineer | Company and Position Summary

Rensair is a high-growth climate technology company on a mission to transform commercial buildings through smarter ventilation, better indoor air quality, and lower energy consumption. Headquartered in London, UK, with operations across the U.S. and Europe, Rensair is scaling its patented Smart Demand-Controlled Ventilation (SDCV) solution globally. Our technology helps organizations reduce energy consumption and operating costs while improving indoor air quality and lowering carbon emissions.

The Lead HVAC Mechanical Engineer will support the growth of Rensair’s UK business and report to the UK CEO. The role involves travelling to new and existing client sites to investigate HVAC and ventilation systems, assess their operation and performance, and support the analysis and optimization of existing systems. Working closely with clients and internal teams, the engineer will help identify opportunities to improve efficiency, reduce energy and emissions, and enhance indoor air quality.

Rensair is “HVAC Hacked,” using connected hardware and software to optimize existing HVAC systems rather than replace them. Our technology enables major organizations to advance their ESG and Net Zero goals while reducing costs, energy consumption, and carbon emissions. This is an opportunity to join a high-growth climate technology company at the intersection of HVAC engineering, building performance, indoor air quality, and decarbonization.

Lead HVAC Mechanical Engineer | Responsibilities

• Lead detailed technical assessments and engineering evaluations of commercial HVAC and ventilation systems to identify opportunities for improved indoor air quality, energy efficiency, and system optimization.

• Collect, document, and analyze HVAC system performance data through field measurements using instruments such as anemometers, pressure gauges, and power meters to assess airflow, pressure, power consumption, ventilation effectiveness, and performance.

• Serve as the primary technical advisor for customers throughout the project lifecycle, including solution development, product selection, implementation, commissioning, and ongoing support.

• Lead technical site investigations, customer meetings, and engineering discussions for new and existing customers.

• Collaborate with Rensair’s global R&D and engineering teams by providing field insights and customer feedback to develop customized solutions and improve future products.

• Prepare technical reports, engineering recommendations, presentations, and documentation for customers and internal stakeholders.

• Partner with the commercial team to support technical evaluations, proposal development, RFP responses, and customer solution strategies.

• Build and maintain strong customer relationships to identify expansion opportunities and ensure long-term success.

• Stay current with HVAC technologies, ASHRAE standards, building automation systems, energy efficiency initiatives, indoor air quality regulations, and commercial building trends.

• Travel to customer sites throughout the UK (approximately 50%).

Lead HVAC Mechanical Engineer | Qualifications

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

• 6–10 years of experience in commercial HVAC engineering, mechanical consulting, MEP engineering, commissioning, building systems, facilities engineering, energy engineering, HVAC controls, or related technical solutions.

• Strong knowledge of commercial HVAC systems, including air handling units (AHUs), rooftop units (RTUs), chilled water systems, ventilation systems, VAV systems, HVAC controls, and building automation systems.

• Experience evaluating HVAC performance, troubleshooting mechanical systems, commissioning projects, or implementing energy optimization initiatives.

• Strong analytical, problem-solving, and technical decision-making skills.

• Demonstrated ability to lead technical projects, influence technical decisions, and collaborate effectively with customers, cross-functional teams, and executive stakeholders.

• Excellent written and verbal communication skills, with the ability to present technical concepts and engineering recommendations to customers, consultants, contractors, and leadership teams.

• Experience in consulting, technical sales support, commissioning, or other customer-facing engineering roles is preferred.

• Ability to work independently in a fast-paced entrepreneurial environment while collaborating effectively with engineering, R&D, and commercial teams.

• Ability to travel approximately 50%.

Lead HVAC Mechanical Engineer | Compensation & Benefits

• Competitive base salary with targeted performance incentive compensation offering On-Target Earnings (OTE) of up to £120,000.

• Equity offering available upon hire.

• Comprehensive healthcare reimbursement.

• 24 days of paid time off plus company holidays.

• Direct exposure to executive leadership and the opportunity to help shape Rensair’s growing UK engineering organization.

• Opportunity for significant career advancement as Rensair continues to expand across the UK and Europe.

• Entrepreneurial culture where innovation, collaboration, and initiative are recognized and rewarded.

• Work with industry-leading technology that helps commercial buildings reduce carbon emissions, improve indoor air quality, and achieve sustainability goals.

• Opportunity to collaborate with an international engineering and R&D team developing next-generation HVAC and clean air technologies.

Pay: £80,000.00-£120,000.00 per year

Education:

• Bachelor's (required)

Experience:

• commercial HVAV engineering: 1 year (required)

• client – facing site: 1 year (preferred)

Work Location: Hybrid remote in London WC1V