Sonia Holzheimer is a mechanical engineer with over 20 years of experience in the building and construction industry, and co-founder of SEQUAL — a Cairns-based consultancy specialising in energy-efficient HVAC design. Her early career included work on some of the country's most ambitious sustainability projects, including William McCormack Place I and II — Australia's first 5-star NABERS and 6-star Green Star office buildings constructed in the tropics. But while these credentials demonstrate what's possible, Sonia's real passion lies in what's practical.

Because most buildings aren't showcase projects. They don't come with generous budgets or integrated BMS platforms — and yet they still need to meet energy efficiency standards under Section J. That's where Sonia's focus is today: helping engineers, designers, and certifiers navigate the sometimes-tricky terrain of compliance for everyday buildings.

Through her Section J training course, Sonia has restructured the content to focus not just on what the clauses require, but why they exist — bridging the gap between compliance and good design practice. She draws on real project experience to equip professionals with the insight and confidence to apply the code in the real world.

A Fellow of Engineers Australia and Registered Professional Engineer of Queensland, Sonia also chairs the Queensland Mechanical College Committee and the Women of AIRAH STG. She is a passionate industry volunteer and advocate for inclusive, visible leadership in engineering and construction.