Building physics is a well-established field of knowledge. Still, that is yet to be consistently translated into practice through state-of-the-art performance, exploring the potential of adaptive comfort and passive thermal behaviour to excel in terms of energy sufficiency in a dialogue with the local climate. This is particularly relevant and well suited in temperate climates, where forefront knowledge for the past 40 years shows it is straightforward to build houses offering healthy and comfortable environments with no or very little need for additional heating and, even less, cooling, while also dismissing the need for active systems. This means exploring the building’s sufficiency even before caring about the efficiency of possibly unnecessary ‘add-on’ equipment. A consistent approach to building design must be adopted in which constraints and parameters with highest impact on the building’s performance in its location and climate are set right from the start of the design process. Those can be, either, fairly location-agnostic (e.g. insulating from the outside while keeping thermal mass indoors), or, definitely, location- and climate-driven (e.g. window sizing and orientation), while others still more occupant- and activity-related (e.g. setting requirements for effective adaptive comfort and healthy building operation). Only a holistic understanding and definition of those parameters in the pre-design stage can guarantee that the subsequent design explores the full potential for energy sufficiency and comfortable and healthy environments. This paper will explore the above, proposing a rationale towards a better housing building stock, and demonstrating the enormous potential for low-energy housing for millions of citizens.