The Passivhaus Standard is optional. There are three classes; Standard, Plus and Premium. Each has defined threshold values for Energy demand, Space heating, Air tightness etc.

Scotland has recently brought in laws that all new schools must be Passivhaus, along with all new dwellings from 2024, such is the high regard for the standard and its robust methodology.

Local Authorities like Bath & North East Somerset, Cornwall and Bristol City Council have (or are about to) introduce local planning legislation equating the energy performance of new homes and commercial buildings to Passivhaus, actively encouraging the use of PHPP as a compliance tool for gaining planning permission. To use PHPP effectively, your team will need a Passivhaus Designer from as early as possible in the design process.

Passivhaus can be applied in any climate in any part of the world for both domestic and commercial buildings.

No. The Passivhaus Standard does not directly address the two metrics used for Net Zero Carbon; Embodied Energy and Energy In Use.

The standard ensures that per square metre of floor space, Passivhaus energy demand will far exceed the performance of an equivalent building that meets normal regulations. If used in combination with on-site renewables, there is no reason why a Passivhaus could not achieve Net Zero In Use or even contribute energy back to the grid.

Definitions for Net Zero Carbon are still not uniform across the industry, and stated values often exclude ‘unregulated energy’ (the power used by appliances with buildings) so are often not a true reflection of how buildings actually perform.

Every project requires a Passivhaus Designer (or Consultant) to proactive lead on the application of the standard and use the compliance software PHPP. This can be a member of the design team (if qualified) or an independent consultant brought in for that purpose.

Qualifications are governed by the Passivhaus Institute, and is typically achieved by attending an intensive training programme covering the principles of the standard, the underlying science behind good building physics and use of PHPP. The software is licensed to the individual, not their company, to discourage mis-use and lowering quality.

The Passivhaus Certifier is an experienced professional who has undertaken additional training and who has greater working knowledge of the standard.

Each project must have an independent certifier, who is able to advise and comment on the evidence provided by the Passivhaus Designer, eventually leading to final sign-off and certification.

There are around 6 firms currently in the UK who offer the Passivhaus Certifier role.

The Passivhaus Planning Package (PHPP) is the compliance tool used to demonstrate that the design will meet the standard. It contains critical data about the location and climate, the u-values of each element, areas and plant in order to make accurate predictions for the building’s energy use. It is an excellent tool for reducing the so-called Performance Gap between design intent and reality.

PHPP software licences rest with the individual (who has passed the exam) not their company.

Mechanical Ventilation with Heat Recovery (MVHR) is a ventilation system that maintains thermal comfort of internal spaces using supply and extract ducts. It maintains excellent air quality by providing a constant supply of fresh (but not cold) air and extracts stale air to outside, having first harvested some heat energy. Systems run off electricity and must be whisper quiet to create no nuisance noise.

The use of MVHR requires space for the plant and ductwork but if considered from first principles it is easy to accommodate. To meet the standard, MVHR units must be highly efficient and have different modes to account for varied occupancies and summer by-pass.

The EnerPHit Standard is applicable to existing buildings using the same components and criteria that assesses a new build Passivhaus. The standard sets slightly lower targets due to the constraints imposed by existing forms, orientation etc. An EnerPHit Retrofit can be phased or undertaken in one go.

No. BREEAM is a holistic assessment method covering additional areas like transport, ecology and pollution. It is often criticised for the credit-based approach that encourages buying points to achieve certification, rather than producing truly energy saving buildings.

Anything that goes into the design of a Passivhaus will have a measurable outcome, and PHPP can be used to optimise the design by running scenarios for say, varied thickness of roof insulation. The true value of each design decision can therefore be demonstrated, and money is not spent simply to tick a box to get another point on the board.

Conventional wisdom says Passivhaus projects will require a greater capital investment due to using premium products (like triple-glazing), additional consultants and possibly longer periods on site due to the greater care the contractor must take to achieve a higher build quality.

However, if designed from first principles, there’s no reason why it should cost more. Trust in the standard means delivering heat via ventilation, which means there’s no need for a conventional heating system. This is a saving. A log-burner will be no use in a Passivhaus, so you could omit the cost of a chimney. It is only when buildings are over specified that they look expensive by comparison.

The long-term benefits are lower energy bills year-on-year, insulation against rising energy prices and a proven higher resale property value. The greater internal comfort that comes with correct relative humidity and temperature also increases productivity and general wellbeing.

Yes. It is recommended that the building is tested first mid-way through the build once the air tightness layer is complete (but still visible should remediation be required) and again at completion. If the air test fails and cannot be remedied, certification is withheld, hence the detailing and quality of on-site installation is achieving the standard.

Compared to hitting Building Regulations compliance, the Passivhaus standard is harder to achieve, reliant on numerous designers, suppliers, and skilled trades throughout the project’s life.

If the building should fall short - for example, by failing the air test - then the Passivhaus Institute offer a lower badge called PHI Low Energy Building Standard.

This acknowledges that the building will still far exceed the performance of equivalent buildings, but protects the integrity of the full Passivhaus standard.