What Is Passive House?
Passive House (or Passivhaus in its original German) is a voluntary construction standard focused on creating buildings that require very little energy to heat or cool. Developed in Germany in the early 1990s by physicist Wolfgang Feist and professor Bo Adamson, the standard is now applied to residential, commercial, and public buildings worldwide.
The term "passive" refers to the strategy of harnessing passive energy sources — solar gain, internal heat from occupants and appliances, and heat recovered from outgoing air — rather than relying primarily on active heating and cooling systems. The result is a building that stays comfortable year-round with a fraction of the energy consumption of a conventional build.
Certified Passive House buildings must meet strict performance thresholds verified through energy modelling and post-construction testing. The standard is not a style — it's an engineering target.
The Five Core Principles
1. Continuous Insulation
A Passive House envelope is wrapped in thick, unbroken insulation — typically far more than minimum building code requirements. The goal is to eliminate heat loss through walls, roofs, and floors to a level where the building behaves like a thermos: slow to lose heat in winter and slow to gain it in summer. Insulation values vary by climate, but wall assemblies in cold climates commonly achieve U-values below 0.15 W/m²K.
2. Elimination of Thermal Bridges
A thermal bridge is any structural connection that bypasses the insulation layer — think of a steel beam passing through a wall, or a concrete balcony slab that projects through the building envelope. These junctions allow heat to conduct rapidly outward in winter, dramatically undermining insulation performance. Passive House design eliminates or rigorously mitigates thermal bridges through careful detailing at every junction.
3. High-Performance Windows and Doors
Glazing is traditionally the weakest point in a building envelope. Passive House buildings use triple-glazed windows with insulated frames, low-emissivity coatings, and inert gas fills (typically argon or krypton) to dramatically reduce heat loss. Window placement is also strategic: south-facing glazing (in the northern hemisphere) is maximised to harvest solar gain in winter, while overhangs and shading prevent overheating in summer.
4. Airtight Construction
Uncontrolled air leakage through gaps in the building fabric accounts for a surprisingly large proportion of heat loss in conventional buildings. Passive House requires meticulous airtightness, verified by a pressurisation test (the "blower door test") that quantifies how much air leaks through the envelope at a given pressure differential. The standard requires no more than 0.6 air changes per hour at 50 Pascals of pressure — far tighter than typical construction.
5. Mechanical Ventilation with Heat Recovery (MVHR)
An airtight building needs controlled ventilation — and this is where Passive House's most distinctive technology comes in. A mechanical ventilation with heat recovery (MVHR) unit continuously supplies fresh air to living spaces and extracts stale air from wet rooms, passing both streams through a heat exchanger. In winter, up to 90% of the heat in outgoing air is transferred to the incoming fresh air stream, dramatically reducing ventilation heat losses. In summer, the system can be bypassed for natural cooling.
What About Cooling?
Passive House originated in cool European climates but has since been adapted for hot and mixed climates through the Passive House Plus and Passive House Premium variants, which incorporate renewable energy generation. For hot climates, the same principles apply in reverse — keeping solar gain out, maintaining a cool interior, and recovering coolth in the ventilation system.
Is Passive House Worth the Investment?
Passive House buildings typically cost more upfront than conventional builds — primarily because of the enhanced insulation, windows, and MVHR system. However, the payback comes through dramatically reduced energy bills over the building's lifetime, improved comfort (no cold spots, no draughts, consistent temperatures), and better indoor air quality from the continuous filtered ventilation.
As energy prices remain volatile and climate targets become legally binding in many jurisdictions, the Passive House standard is increasingly viewed not as a luxury but as the logical baseline for responsible construction.