Passivhaus

The gold standard of energy-efficient design

Passivhaus, or Passive House, is an advanced, low-energy construction standard for buildings. 

By using high performance insulation and making a building completely draught feee, it effectively eliminates heat loss to create a building with very low heating requirements and a low environmental impact.

This can help create buildings which use around 75% less energy compared to a standard UK newbuild property.

A Passivhaus is an extremely airtight, highly insulated and low energy home.

A mechanical means of ventilation removes stale air and replaces this with fresh, clean air.

Great care must be taken to ensure the airtight integrity of the property is maintained.


No air leakages 

A Passivhaus is effectively “wrapped” in an airtight membrane which must be protected from damage throughout the lifetime of the building. 

This means that great care must be taken during any future maintenance or refurbishment of the building. The occupants and those responsible for maintaining the property must be aware of where the membrane is and how to protect it.


No thermal bridges

A thermal bridge is like a road for heat - warm air can travel right through your wall and outside your home.

Most homes have thermal bridges in the walls, floors and roof. Anything that breaks the continuity of the insulation is a thermal bridge, even timber. 


Triple glazed windows 

These windows retain as much heat as possible.

Made of triple-pane insulated glazing, the gaps between the glass panes are sealed and filled with argon or krypton gas. The technology also includes a ‘low-emissivity’ coating, ‘warm edge’ glass spacers and specially developed thermally broken window frames.

Correct sizing and placing of the windows, along with the correct orientation of the building, ie. the direction the main elevations face, will minimise heat loss and maximise solar gain.


Proper orientation

In order to benefit from solar gain, a Passivhaus requires the glazing to be optimised on the south elevation with reduced glazing on the north elevation. 

With good design, it is possible to reduce the glazed area of the south elevation to approximately 25-35%.

Habitable rooms, such as living rooms and bedrooms, should be positioned on the south side of the building as the larger windows will provide a pleasant ambiance with good daylight.


Mechanical ventilation

Because a Passivhaus is very airtight, a Mechanical Ventilation Heat Recovery System (MVHR) is required. This extracts warm air from certain rooms, such as kitchens and bathrooms, and supplies fresh air to others.