Passive House (or Passivhaus) is one of the world’s most comprehensive building performance standards for energy efficiency in residential homes. Passive houses are those that maximise energy efficiency through ‘passive’ means, primarily insulation, space heating, airtightness and heat recovery.
Passive House standards are notoriously hard to achieve in buildings that include balconies. This is because balcony penetrations can account for a disproportionate share of total envelope heat less in otherwise high-performance assemblies. This is because balconies require penetrations into the facade to set the anchors, which then act as thermal bridges (carrying heat out of the building, and bringing the cold in).
In cold climates, such as Canada, even minor discontinuities can drive interior surface temperatures below dew point, making the anchor penetration locations significant weak points that many architects will simply exclude altogether.
However, it is eminently possible to design a building to Passive House standards while including balconies. In this article, we’ll explore some best practices. But first, let’s understand where the Passive House movement came from, and why it matters today.
The Passive House movement began in the 1980s, spearheaded by physicists Bo Adamson and Wolfgang Feist. Their initial concept was to develop a home that could maintain optimal comfort through passive energy generation (primarily solar power and heat recovery ventilation). This led them to create the first Passive House in Darmstadt in 1990, which achieved 90% less heating demand than conventional buildings.
Six years later, Feist founded the Passive House Institute (PHI) to formalise the standards and to award certification to homes and elements that succeeded in achieving them.
Since then, the Passive House Institute has certified tens of millions m² of residential living space worldwide, at a rate that has been increasing exponentially since 2010. Three-quarters of this space is concentrated in Europe, but Passive House projects are becoming increasingly popular in East Asia, North America and Australia – best signified by the ever-growing number of regional Passive House Affiliate Organisations.
The core principle of a Passive House is that it should be constructed to minimise the need for heating and cooling sources (such as radiators and air conditioning) while still achieving a high level of comfort. This ensures the house produces a lower carbon footprint, while also being more cost-effective to run.
Overall, the benefits of a Passive House include:
To be certified a Low-Energy Building by the Passive House Institute, residential constructions must achieve specific grades across eight key principles. These are:
| Criteria | Description | PHI Low Energy Building | Passivhaus Classic |
|---|---|---|---|
| Airtightness | Eliminates drafts and outside pollutants | <1 ACH @ 50Pa | <0.6 ACH @ 50Pa |
| Space Heating Demand | Annual energy needed to keep internal spaces warm | <30 kWh/m² | <15 kWh/m² |
| Heating Load | Comfort on the coldest day of the year | – | <10 W/m² |
| Primary Energy Renewable | Total renewable energy needed to run the building | <75 kWh/m² | <60 kWh/m² |
| Renewable Energy Generation | Energy generated from renewable sources where possible | -* | -* |
| Summer Overheating | Resists overheating by allowing heat to escape | <10% exceeding 25°C | <10% exceeding 25°C |
| Surface Temperature | Keeps the building envelope above minimum temperature thresholds | – | >17°C |
| Ventilation | Continuous fresh air supply without opening windows | >30m³/hr/person | >30m³/hr/person |
* Only required with Plus and Premium Passive House criteria.
The PHI and accredited certifiers assess both buildings and construction components to certify them to Passive House standards. In both cases, the process is notoriously rigorous.
For buildings
The process of certifying a building to Passive House standard is not a single test that happens at the end, but a staged quality assurance process that runs throughout. It typically takes place in four stages:
For components
A Passive House component is a high-performance building element certified by the Passive House Institute to be around two to four times more energy efficient than a standard product in the same category. Passive House components are those that are more likely to contribute to a successful Passive House project and are favoured among Passive House developers. A list of all certified Passive House products can be found on the Component Database.
The process for certifying an individual component is no less stringent than for an entire building, and usually occurs across three steps:
The Passive House Institute’s Component Database includes a list of balcony connections. When certifying connections for both cantilevered and supported balconies, the PHI looks for systems that:
Passive House-compatible balcony connections are those that can manage one of the most challenging junctions in the building envelope. Since a balcony connection passes from the outside to the inside of the building, it can act as thermal bridge – carrying warmth out of the home, while bringing coldness in from outside.
To meet Passive House standards, balcony connections must limit heat loss, prove resistant to condensation, and maintain a stable surface temperature while still performing their primary function: providing a strong, stable support for the balcony structure.
Therefore, when assessing balcony connections, the PHI will holistically assess the thermal performance, moisture control and structural capacity of the component.
Here are the stages Sapphire’s G30 anchor went through while being assessed by the Passive House Institute:
Sapphire proved its intent to satisfy Passive House standards by highlighting early design drivers such as reducing the number of penetrations into the building envelope.
Sapphire submitted 2D and 3D models of the G30 anchor for testing in simulated conditions. The PHI tested these models for heat flow through the connection point to determine whether the component met acceptable χ‑value (point thermal transmittance) limits when integrated into compliant wall build‑ups. Crucially, this modelling was assessed within a variety of PHI‑approved climate zones, which include cold and cool‑temperate climates.
Many Passive House projects forego balconies as they were widely seen as a risk to achieving Passive House certification.
But recent innovations such as Sapphire’s G30 anchor have made it possible to design balconies into Passive House projects without compromising thermal bridging or internal surface temperature standards at the connection points. This means it’s now possible to design buildings that include balconies while still achieving Passive House standards.
If you’re designing a Passive House project and are hoping to include balconies, Sapphire could help you achieve your aspirations. Speak to us today to learn how we could support your project.
