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.

The interior surface of the glazing stays around 17 to 18°C in the depths of winter^{1PHI Criteria v10c, § 2.4.5 "Minimum thermal protection": no more than 4.2 K below the operative temperature, checked at 22 °C (≈ 17.8 °C); floor ≥ 19 °C. Passipedia cites "over 17 °C" in practice.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.

20–22°C

Stable temperature in winter, no draughts

< 1 000 ppm

Indoor CO₂ — benchmark for good air quality (FOPH)^{2FOPH 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

Interior glazing surface temperature in winter

40–60 %

Relative humidity — optimal comfort

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 is enough to maintain a comfortable temperature.

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

Five non-negotiable rules

The Passivhaus standard rests on five construction principles. Two of them are building certification 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 and certifies the passive standard — 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, frame and installation 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 avoids any loss due to ventilation.

How much does it consume?

Heating demand is measured in kWh per square metre per year. The comparison speaks for itself.

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

Space heating demand (PHPP indicator). The passive standard uses 8 to 10 times less heating energy than an unrenovated existing building^{9The PHI threshold of 15 kWh/(m²a) covers space heating demand alone, referred to the TFA (PHPP). It is not directly comparable to a Minergie index or to metered heating + hot water consumption.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}. Plus and Premium share the same heating threshold as Classic: they differ in renewable primary energy (PER ≤ 45 and ≤ 30 kWh/m²·an) and renewable energy generation (≥ 60 and ≥ 120 kWh/m²·an)^{10PHI 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·an 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·an^{11PHI 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^{12Minergie 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)^{13Minergie 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 Rénovation define specific targets.

EnerPHit target : ≤ 25 kWh/m²·an^{14PHI Criteria v10c, Table 3 (heating demand method): 25 kWh/(m²a) in a cool-temperate climate — French-speaking Switzerland. 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}, i.e. 75 to 90% less heating energy than before the retrofit according to the Passivhaus Institut, with incomparable comfort.

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.