Passive House

Committed to designing low carbon and energy efficient buildings, PKA Architects have recently become certified Passive House Designers.

Developed by the PassivHaus Institute (PHI) the Passive House standard strives to significantly improve a buildings energy performance. Passive House design ultimately results in a higher level of comfort for a buildings occupants through good heating and ventilation strategies that use very little energy. This can be adopted not only on new buildings but also as a retrofit standard for refurbishment projects.


‘The heat losses of the building are reduced so much that it hardly needs any heating at all. Passive heat sources like the sun, human occupants, household appliances and the heat from the extract air cover a large part of the heating demand. The remaining heat can be provided by the supply air if the maximum heating load is less than 10W per square metre of living space. If such supply-air heating suffices as the only heat source, we call the building a Passive House.’

Univ. Prof. Dr Wolfgang Feist Director of the Passive House Institute, Darmstadt, Germany.


Why Passive House?

Passive House design has been proven to reduce space heating requirements by up to 75% when compared to other standard new builds in the UK. This method of design and construction has many and varied benefits:

  • Minimised energy consumption

  • Increased thermal comfort

  • Lower energy bills

  • Optimised life cycle costs and

  • High standards of indoor air quality

The video below provided by the PassivHaus Trust provides an introduction to Passive House and it’s credentials.


What is the Passive House standard?

For a building to be considered a Passive House there are a number of technical criteria that need to be achieved, including:

  • Space Heating Energy Demand is to not exceed 15 kWh per square meter of net living space (treated floor area) per year or

  • 10 W per square meter peak demand

  • The Renewable Primary Energy Demand comprising the total energy to be used for all domestic applications (heating, hot water and domestic electricity) must not exceed 60 kWh per square meter of treated floor area per year

  • Airtightness must achieve a maximum of 0.6 air changes per hour at 50 Pascals pressure (ACH50)

  • Thermal comfort must be met for all living areas during winter as well as in summer, with not more than 10 % of the hours in a given year being over 25°C.

The above criteria can be achieved through intelligent design and implementation of the 5 Passive House principles:

  • High levels on insulation

  • Extremely high performance windows and insulated frames

  • A MVHR (Mechanical Ventilation Heat Recovery) system with highly efficient heat recovery

  • Airtight building fabric

  • Absence of thermal bridges


In order to achieve Passive House certification, a project will be reviewed by an independent certifier who will rigorously assess the building to see if it complies with the Passive House standard in meeting all Quality Assurance requirements as set out by the Passive House Institute.

If Passive House is of interest to you and you would like to discuss a new build or retrofit project further please do not hesitate to get in touch.