Passive House and Passivhaus refer to the same building performance standard. Passivhaus is the German original, developed by the Passivhaus Institut (PHI) in Darmstadt; Passive House is the English-language equivalent used in the UK, Ireland, and North America.

Both terms describe a standard targeting a heating demand of no more than 15 kWh/m²/yr, an airtightness of ≤0.6 ACH50, and a peak heating load of ≤10 W/m². The standard is identical; the spelling depends on context and audience.

For PHI-certified Passivhaus in the UK, windows typically need to achieve a whole-window U-value (Uw) of ≤0.80 W/m²K, assessed through the PHPP (Passive House Planning Package) calculation. The exact threshold depends on the building's orientation, total glazed area, wall U-values, and climate zone.

In practice, most UK certified Passive House projects specify windows with Uw between 0.70 and 0.80 W/m²K. Norrsken's triple-glazed alu-clad timber windows achieve whole-window U-values from 0.64 W/m²K, comfortably meeting this threshold.

Norrsken provides psi-value data and works directly with PHPP assessors to ensure specification accuracy.

Passive House certification requires a measured airtightness of ≤0.6 ACH50, verified by a blower door test. This is approximately 20 times more airtight than a standard UK new build.

Achieving this level requires careful attention to the whole building envelope. Window installation quality is a significant variable: a correctly specified window installed poorly will fail the blower door test.

The comfort, energy, and air quality benefits of Passive House construction come from the building itself, not from the certificate. Formal PHI certification is a third-party verification process - valuable, but not the source of the performance.

Many UK self-builders choose to build to passive house performance levels without pursuing certification, either to reduce cost and programme time, or because their project falls outside the certification criteria. Norrsken supports both certified and non-certified projects.

We recommend discussing your goals with a Passivhaus designer early in the process to decide which route suits your project.

Building a Passive House typically requires windows with U-values of 0.80 W/(m²K) or lower.

Many suppliers produce Passive House-compliant products, but how they operate differs significantly.

Look for:

• Construction quality: aluminium-clad timber is the optimal choice for Passive House windows
• Installation expertise
• Certification and technical support
• One partner, start to finish.

To learn more, read our guide to ordering Passive House windows.

Passive House Classic, Plus, and Premium are three certification tiers introduced by the Passivhaus Institut in 2015. Classic meets the original standard: a heating demand of ≤15 kWh/m²/yr and airtightness of ≤0.6 ACH50.

Plus requires the same fabric performance criteria plus on-site renewable energy generation of at least 60 kWh/m²/yr (Primary Energy Renewable). Premium requires ≥120 kWh/m²/yr renewable generation.

For most UK homeowners and self-builders, Classic is the relevant target. Plus and Premium matter most for larger schemes where energy generation credentials carry planning or marketing value.

Yes - and the UK climate is better suited to Passive House construction than is often assumed.

The standard was developed in Northern European climates closely comparable to the UK, where heating rather than cooling is the dominant demand.

A correctly built passive house in the UK typically uses 80–90% less energy for space heating than an equivalent standard new build. Most residents report eliminating or dramatically reducing their reliance on conventional heating systems.

The additional build cost is typically 5–15% above a standard new build, offset by running cost savings, improved thermal comfort, and the elimination of cold spots and condensation.

The build cost uplift for a UK Passive House is typically 5–15% above a code-compliant standard new build.

This range reflects significant variation in project scale, complexity, and specification.

Costs have narrowed as the supply chain has matured - certified components including windows, doors, MVHR units, and airtightness materials are more widely available than a decade ago.

Offsetting factors include reduced or eliminated heating system costs and lower running costs over the building's lifetime. AECOM studies suggest the cost uplift can be a little as <1% for a new build.

The Passivhaus Trust publishes cost data from UK projects. Norrsken's team can provide window and door costs as part of an early-stage budget discussion.

Passive Houses in the UK typically exceed an EPC A rating, which is associated with measurable value uplift as buyers and lenders increasingly price in running costs.

Evidence from Germany and Austria consistently shows a value premium of 5–10% over comparable standard properties.

As the Future Homes Standard raises baseline expectations for new build performance, properties already built to passive house standard are likely to carry a stronger relative advantage.

Comfort, noise reduction, and indoor air quality benefits also contribute to perceived value in ways that are harder to quantify but consistently cited by owners.

Winmill Farm in Oxfordshire - a Passive House that achieved an air test result of 0.45 ACH - requires no heating at all, despite being located in a colder UK climate zone.

Certified Passive House Classic buildings have a peak heating load of ≤10 W/m² - low enough that a conventional boiler is often unnecessary.

Heat generated by occupants, appliances, and solar gain through glazing is usually sufficient for most conditions.

A small supplementary heat source - sometimes nothing more than an electric element within the MVHR unit - is typically sufficient for the coldest periods.

Winmill Farm in Oxfordshire - a Passive House that achieved an air test result of 0.45 ACH - requires no heating at all, despite being located in a colder UK climate zone.

Triple glazing is the only glazing option capable of reliably achieving the whole-window U-value of ≤0.80 W/m²K that Passivhaus PHPP calculations require for UK climates.

The standard does not mandate triple glazing by name, but the physics makes it the practical necessity.

The best double-glazed windows achieve Uw values of around 1.2 W/m²K - significantly above the passive house threshold. Triple glazing also delivers superior airtightness at the window-to-frame junction.

Norrsken windows specified for passive house projects are triple-glazed, achieving whole-window U-values from 0.64 W/m²K.

For a full breakdown of what this means for your specification and budget, see our guide to triple glazing for Passive House self-builds.

Yes. Mechanical ventilation with heat recovery (MVHR) is a core requirement of the Passivhaus standard and is not optional for certified buildings.

The extreme airtightness of a passive house - ≤0.6 ACH50 - makes natural ventilation insufficient to maintain indoor air quality.

MVHR continuously supplies fresh filtered air to habitable rooms and extracts stale air from wet rooms, recovering 75–90% of the heat from outgoing air. Without it, the airtight envelope that delivers the energy performance would create dangerously poor air quality.

Norrsken supplies windows and doors. MVHR systems are supplied by specialist ventilation contractors, and we work with your design team to coordinate installation details.

Passive house principles scale well to multi-unit residential schemes, and several UK housing associations and developers have delivered certified passive house developments.

Benefits at scheme level include very low predicted energy bills, EPC A ratings, and fabric performance that anticipates - and surpasses - Future Homes Standard requirements.

The additional upfront cost is offset by reduced heating system specification, lower maintenance costs, and reduced exposure to future regulatory uplift.

Norrsken works with developers and their architects on multi-unit schemes, offering technical support and in-house installation under a single contract. Contact our team to discuss your scheme.

A well-designed passive house does not overheat in summer - but this is a design outcome, not an automatic feature of the standard.

Overheating is prevented through shading design, controlled ventilation, and careful management of south-facing glazing areas, all modelled in PHPP before construction.

Part O of the Building Regulations (introduced 2022) requires overheating risk to be assessed for new residential buildings, bringing mainstream regulations closer to the passive house approach. Triple-glazed windows with solar control glass coatings can reduce solar heat gain where required.

Poor passive house design, particularly excessive south-facing glazing without shading, can result in overheating.