What is passive construction?

First and foremost, a building that is pleasant to live in

The paradox of the passive house: in seeking to reduce energy consumption, what you get above all is remarkable comfort. No cold draughts near windows. No cold surfaces. Constant air quality.

In front of the glazing, the radiant temperature does not fall, by calculation, below 17 to 18 °C in the depths of winter^{1PHI v10c, § 2.4.5: for windows, radiant temperature 0.5 m in front of the glazing no more than 4.2 K below operative, checked in PHPP at 22 °C (≈ 17.8 °C); floor ≥ 19 °C.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — § 2.4.5 Minimum thermal protection2023-01-20 · accessed 2026-09-04} — eliminating the cold-surface sensation typical of ordinary buildings.

≤ 10 %

Hours of the year above 25 °C, without active cooling (PHI criterion)^{2PHI v10c, § 2.4.1: share of hours in the year with indoor temperature above 25 °C ≤ 10 % for buildings without active cooling. Calculated in PHPP.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — § 2.4.1 Frequency of overheating2023-01-20 · accessed 2026-10-01}

< 1 000 ppm

Indoor CO₂ — benchmark for good air quality (FOPH)^{3FOPH topic sheet B: below 1000 ppm indoor air quality is rated good to very good; above it, fatigue increases. SIA 382/1:2014, the edition cited by the FOPH, places 1000–1400 ppm in category INT 3.Office fédéral de la santé publique (OFSP) — Aérer correctement — Fiche thématique B : Évaluation de la qualité de l'air intérieur2019-02-28 · accessed 2026-09-04}

≈ 17–18°C

In front of the glazing in winter (PHI design criterion)

≥ 19 °C

Floor surface temperature (PHI criterion)^{4PHI v10c, § 2.4.5: 'The floor surface temperature must not fall below 19 °C', checked in PHPP for a 22 °C room temperature and the minimum outdoor temperature of the climate data set.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — § 2.4.5 Minimum thermal protection2023-01-20 · accessed 2026-10-01}

A passive house does not heat. It conserves.

The idea is radical in its simplicity: instead of offsetting heat losses with a large heating system, you start by eliminating them. A very well insulated envelope, free of defects, captures solar heat and heat from the occupants — and retains it.

The result: a building that can do without conventional heating, or almost. The heat given off by occupants, electrical appliances and the sun covers a large share of the losses; the remainder can be supplied through the ventilation supply air, with no radiator network — that is the Passivhaus Institut's functional definition^{5Passipedia, definition: 'thermal comfort in winter can be achieved solely by heating the supply air required for hygienic reasons' — hence a heating load of about 10 W/m².Passipedia — Passive House Institute — The Passive House – definitionaccessed 2026-10-01}.

First passive house in France, 2006. Large south-facing windows, timber frame structure, louvre solar shading.

Five construction principles, four verified criteria

The Passivhaus standard rests on five construction principles. The Passivhaus Institut itself checks four criteria on the building: heating demand (or heating load), cooling demand, airtightness and renewable primary energy^{6PHI v10c, Table 1: heating demand ≤ 15 kWh/(m²a) or heating load ≤ 10 W/m²; cooling + dehumidification; n50 ≤ 0.6 h⁻¹; renewable primary energy (PER). U, Uw and η are in Table 2.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — Tableau 12023-01-20 · accessed 2026-10-01}. Two of the five principles coincide with those criteria — heating demand and airtightness; the other three are the component target values for a cool-temperate climate, as the Passivhaus Institut (PHI) — the Darmstadt institute that defines the passive standard and certifies buildings, directly or through accredited certifiers — sets them in Table 2 of its criteria — the EnerPHit component method. It is this overall coherence that guarantees performance.

The five symbols, in plain words. U is the thermal transmittance of a finished building element: the heat that passes through one square metre per degree of temperature difference — the lower it is, the better the element insulates. Uw is the same figure for the whole window, glazing and frame included; the PHI criterion applies to the installed window (installed Uw), installation thermal bridge included. η (eta) is the heat recovery efficiency of the ventilation system: the share of the outgoing air's heat returned to the incoming air. n₅₀ is the number of times the building's whole air volume is exchanged in one hour during a 50-pascal pressurisation test — the measure of airtightness. ψ (psi) is the extra heat loss of a thermal bridge, per metre of junction and per degree of temperature difference.

Heat recovery ventilation (HRV) deserves particular attention: often misunderstood, it is inseparable from the passive standard. It continuously renews the air while recovering the heat from the extracted air — which sharply reduces ventilation heat losses without eliminating them: the criterion above requires at least 75 % to be recovered.

How much does it consume?

Heating demand is expressed in kWh per square metre per year.

Read these as orders of magnitude: the energy reference area is not calculated the same way from one standard to the next.

Two quantities of different kinds: the Geneva IDC threshold (IDC — heating expenditure index) is a metered consumption, heating and hot water included; the Passivhaus value is a calculated heating demand, on a different reference area^{12PHI v10c, Table 1, note 1: the 15 kWh/(m²a) threshold is a demand calculated in PHPP, referred to the TFA. It does not compare directly with a metered heating + hot water consumption such as the IDC.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — Tableau 1, note 12023-01-20 · accessed 2026-09-04}. Minergie sets no absolute value and is therefore not shown: for new builds, ≤ 90 % of the MoPEC 2025 limit^{13Minergie regulation 2026.1, cl. 6.1: Qh (SIA 380/1:2016) ≤ 90 % of the MoPEC 2025 Qh,li for new Minergie buildings, ≤ 70 % for Minergie-P; minimum 15 kWh/(m²a). No "30–40" figure appears in it.Association Minergie — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, Version 2026.1, ch. 6.12026-01-08 · accessed 2026-08-20}. Plus and Premium share the same heating threshold as Classic: they differ in renewable primary energy (PER ≤ 45 and ≤ 30 kWh/m²·yr) and renewable energy generation (≥ 60 and ≥ 120 kWh/m²·yr)^{14PHI Criteria v10c, Table 1: PER ≤ 60 / 45 / 30 kWh/(m²a) and renewable generation ≥ – / 60 / 120 kWh/(m²a) for Classic / Plus / Premium. No class is defined as "energy-positive".Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — Tableau 12023-01-20 · accessed 2026-09-04}. MoPEC — the cantons' model energy regulations — is the common baseline from which each canton derives its own energy act: it is not a directly applicable federal standard.

What these 15 kWh/m²·yr are, and are not. This is a calculated space heating demand, related to the reference floor area: it includes neither domestic hot water, nor appliance electricity, nor lighting. It is therefore not the figure you will read on your bill, and it does not compare directly with a Minergie indicator or with metered consumption.

Passivhaus or Minergie-P? Both aim at the same level of performance by two different calculation routes: Passivhaus sets an absolute heating demand — ≤ 15 kWh/m²·yr^{15PHI Criteria v10c, Table 1: heating demand ≤ 15 kWh/(m²a) referred to the TFA, OR alternatively heating load ≤ 10 W/m². The same threshold applies to Classic, Plus and Premium.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — Tableau 12023-01-20 · accessed 2026-09-04} —, Minergie-P a percentage: ≤ 70 % of MoPEC 2025 limit values, whose cantonal transposition is under way^{16Minergie regulation 2026.1, cl. 6.1, table: Minergie-P ≤ 70 % of the MoPEC 2025 Qh,li for new build and ≤ 90 % for retrofits, all building categories, with a floor of 15 kWh/(m²a).Association Minergie — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, Version 2026.1, ch. 6.12026-01-08 · accessed 2026-08-20}, and prohibits fossil fuels for heating and domestic hot water, with exceptions (regulation 2026.1)^{17Minergie regulation 2026.1, cl. 8.1: fossil fuels banned for heating and hot water, with four derogations (peak load, CHP, district heating ≤ 50 % fossil, grid electricity).Association Minergie — Règlement des labels MINERGIE®/MINERGIE-P®/MINERGIE-A®, Version 2026.1, ch. 8.12026-01-08 · accessed 2026-08-20}. Which of the two to aim for, what each actually requires and how equivalence is demonstrated is the subject of the Energy labels → dossier.

EnerPHit: the passive standard for existing buildings

Retrofitting to the passive standard is possible, but the constraints of existing buildings — geometry, structure, unavoidable thermal bridges — call for adaptations. The EnerPHit standard (Passivhaus Institut) and Minergie®-P, with its own retrofit requirements, define specific targets.

EnerPHit target : ≤ 25 kWh/m²·yr^{18PHI Criteria v10c, Table 3 (heating demand method): 25 kWh/(m²a) in a cool-temperate climate. By zone: 35 arctic, 30 cold, 20 warm-temperate, 15 warm.Passive House Institute (PHI), Darmstadt — Criteria for Buildings — Passive House, EnerPHit, PHI Low Energy Building, version 10c — Tableau 32023-01-20 · accessed 2026-09-04}. According to the Passivhaus Institut, heating savings of 75 to 90% are achievable in retrofits^{19Passipedia, EnerPHit page: 'Significant heating/cooling energy savings of between 75 and 90 % can be achieved even in existing buildings' [Bastian 2022]. Achievable, not guaranteed.Passipedia — Passive House Institute — EnerPHit – the Passive House Certificate for retrofitsaccessed 2026-10-01}.

Valid for any new build or high-performance energy retrofit: the logic of the five pillars remains the guiding thread.

Retrofit in progress: insulation and careful attention to envelope details determine the final performance.

What we often hear. And the reality.