Nearly zero-energy building (NZEB) requires the training of millions of construction workers and significant upgrading of vocational education and training (VET) systems across the European Union. This paper shows how an approach to VET based only on learning outcomes and targeting specific skills is too narrow and lacking in depth to allow for the systematic application of theoretical low-energy construction (LEC) knowledge to practice and develop NZEB expertise in the workplace. Theoretically broader, deeper, more technical and interdisciplinary expertise is needed to build to LEC standards and meet European Performance in Buildings Directive (EPBD) targets. Instead, VET for LEC has been largely confined to short and task-specific continuing vocational education and training (CVET) courses, illustrated in the cases of both Slovenia and Ireland and ranging from a narrow, learning outcomes approach to a broader, standards-based approach linking theoretical considerations to specific applications. Mainstreaming the knowledge, skills and competences required for NZEB into initial vocational education and training (IVET) curricula is rare. Though less successful in Finland, it is achieved in Belgian construction IVET, which takes a standards-based approach, successfully embeds LEC elements, and seeks to overcome occupational boundaries and develop a holistic understanding of the construction process.