Passive House windows, certified and suitable.

The Passive House (or Passivhaus, in Europe) standard is a building standard and construction concept designed to drastically increase the energy efficiency, comfort and longevity of a newly built property.

German physicist Wolfgang Feist founded the Passivhaus Institute (PHI) and created the Passivhaus performance standard.  

Passive Houses achieve their high level of performance by meeting exacting criteria in five main areas of the building’s envelope:

- thermal insulation;
- energy-efficient triple-glazed windows;
- effective ventilation;
- airtight construction; and
- elimination of thermal bridging and ‘cold spots’.

Passive houses make use of existing energy sources, such as solar heat entering the building or the body heat of its inhabitants, to heat the building.

Careful planning in the design and construction stages of the building ensures that the home is both very thermally efficient and provides an extremely comfortable living experience.

Passive buildings’ heating demand is capped at 15kWh/m2 per year - 80-90% less than the average domestic building.

Passive Houses are designed to use passive heating sources such as sunlight and body heat to keep the building warm. Some Passive Houses are even built with no central heating system, although most use some form of active heating. 

Passive house requirements are performance-based. 

Windows must have a whole window U-value of 0.80W/(m²K) or less to be suitable. They are usually triple-glazed, with insulated frames or thermal breaks, one or more panes of Low-Emissivity (Low-E) glass, and contain inert gas between the glass panes. 

Norrsken supplies the UK’s only Passive House certified outward opening alu-clad timber window.

You can open the windows in a Passive house to let fresh air in.

This is the simplest and cheapest way of cooling your home in summer. Passipedia recommends having "at least one window in each room openable and having a tool to keep it fixed at a specific level".

Solar gain, particularly through glazing on the south façade, is used as a heat source in passive houses, but too much glass causes overheating in high temperature periods.

This is inefficient if cooling must be used and uncomfortable for occupants. The PHPP is used to balance these factors at the design stage. 

No. Passive houses are designed to be comfortable in both low and high temperature periods.

High levels of insulation actually help to keep the indoor temperature low in well-ventilated buildings during the summer. Read more about Passive Houses in summer here.

Net zero homes must produce as much energy as they use in a year, generally incorporating renewable energy resources to do so, while Passive Houses’ heating demand must not exceed 15kWh/m2 annually.

This is achieved by meeting more stringent criteria in the building design and construction than Net Zero requirements, so Passive Houses may require less solar energy to reach Net Zero.

The benefits of Passive Houses include energy savings, lower heating costs, and a more durable, low-maintenance building.

They also offer a healthier, more comfortable living environment, along with financial advantages like reduced energy tariffs and increased eligibility for green mortgages.

Yes. Passive House buildings are eco-friendly by definition:

"They use extremely little primary energy... The additional energy required for their construction [embodied energy] is insignificant compared with the energy they save later on." (Passipedia) 

Passive houses use MVHR systems to supply fresh air consistently throughout the building.

This ensures a higher quality, more hygienic and relatively condensation-free air supply. The risk of mould, damp and cold spots is reduced - healthier for the inhabitants, and more comfortable than in a typical home. 

It’s generally, but not always, true that Passive House construction costs more in components than a standard build.

“Compared with standard construction, building to the Passivhaus standard incurred an extra cost of approximately 8%” (The Passivhaus Trust).

AECOM found that the capital costs of new builds reimagined as Passive Houses were estimated to increase by less than 1%.

MVHR, wall & roof components are the largest extra-over costs on average.

However, these may be offset as heating systems in Passive Houses tend to cost less than typical builds. Passive buildings’ heating demand is capped at 15kWh/m2 per year - 80-90% less than the average domestic building - which may offset component costs.  

Important early design decisions including building form, orientation & window design can drive efficiency. 

Offsetting these design savings against the extra costs for the higher quality fabric, it is possible to deliver higher quality Passive House buildings at no extra cost by recouping the extra you spend on systems. Whether this is achievable in practice will vary from project to project.

Passivhaus delivers a 30% saving on energy bills compared to a typical new build using either a gas boiler or an Air Source Heat Pump (source: Passivhaus Trust).

Passive buildings’ heating demand is capped at 15kWh/m2 per year - 80-90% less than the average domestic building - which may offset component costs.  

The Passivhaus Trust is a UK affiliate of the International Passive House Association (iPHA).

The PHT promotes the adoption of Passivhaus in the UK.

Learn how to order Passive House windows - and how to compare suppliers.