What is Passivhaus?

The Passive House or Passivhaus Standard is a building standard developed by Wolfgang Feist and Bo Adamson in the 1990’s. Going beyond energy saving, it’s primary focus is directed toward creating a comfortable, healthy low energy building, optimised for energy efficiency. This means that Passivhaus buildings are thermally efficient envelopes which reduces space heating demands of a typical new build by 80%. This results in a comfortable building year round, with low carbon emissions. The standard can be met using a variety of designs, construction methods and technologies and is applicable to any building type, not just houses.

Passivhaus Principles

  • Efficient Shape
  • Super Insulation
  • Minimal Thermal Bridges
  • Super Efficient Windows
  • Draft Free Detailing
  • Good Solar Orientation
  • Efficient Mechanical ventilation with heat recovery
Howe Park Passivhaus

Key Principles of Passivhaus Design

The main advantages of Passivhaus design is COMFORT. High comfort levels and healthy buildings are achieved by reducing heating losses to a minimum through efficient design and meticulous attention to detail. Passivhaus utilizes the concept of a tea cosy. Buildings are wrapped in insulation, thereby preventing heat losses through poorly insulated walls, floors, ceilings and glazing. Air infiltration is controlled by reducing losses through leaky construction such as poorly fitted windows and services penetrations to 800% less then current building regulation requirements. Fresh filtered incoming air is delivered to all rooms by highly efficient mechanical ventilation and heat recovery system (MVHR) systems.

Thermal bridges are the transfer of heat through a conductive material, bypassing your insulation. They are important in highly efficient buildings bacause they can contribute a large proportion of the buildings heat losses. Heat flows spontaneously from hotter to colder regions. Therefore resulting in cold surfaces, which are vulnerable to condensation, mould and rot. As a result you will experience the sensation of a draft. So in a Passivhaus its vital to consider the structure of the building to limit items which cross through the insulation layer, through good well thought through detailing.

An efficient MVHR is a crucial element of your build. In the cold month these ventilation systems will utilise the warmth in the stale exiting air to precondition fresh incoming air, meaning as little as a degree loss. And in the hot months the system utilises the cooler temperatures indoors to precondition the incoming air. Therefore, on all but for extreme days space heating or cooling is rarely required.

Hale House Passivhaus

Key Principles of Passivhaus Classic:

  • Specific space heating demand ≤ 15 kWh/(m²a)
  • or Heating load ≤ 10 W/m²
  • Specific space cooling demand ≤ 15 kWh/(m²a)
  • Specific primary energy demand ≤ 60 +/- 15 kWh/(m²a) (up to 75 kWh/(m2a) with additional renewables)
  • Air changes per hour ≤ 0.6 @ n50

Passivhaus and Beyond

Because of the increased understanding of the need for energy efficiency and the need to achieve zero carbon, coupled with rapidly advancing technical understanding means that projects are increasingly pushing further than Passivhaus Classic. Therefore the Passivhaus institute additionally offer certification to ‘Passivhaus Plus’ and ‘Passivhaus Premium’.

Additionally to meeting the classic standard requirements, Passivhaus Plus projects produce almost as much renewable energy as occupants consume. The amount of renewable energy required depends on the building footprint. Then Passivhaus Premium goes even further by producing more energy than required to heat and operate the building.

Carrstone Passivhaus Plus

Independently Certified & Proven Effectiveness

1991 saw the first houses built to the Passivhaus standard completed. There are in excess of 5,700 independently certified Passivhaus recorded on the Passivhaus Institute (https://passivehouse-database.org). There is an ever increasing number with projects across the globe both new build and retrofit. The independent certification process means that buildings meet the standard, without diluting the value or aims of standard. Concsequently, the Passivhaus plaque remains a badge of honour. Recent research on the original Passivhaus demonstrates that even after 30 years the house continue to function as the Passivhaus standard. So we know that Passivhaus works equally well for both new building and retrofits.

Passivhaus Certification Plaque

Our Experience

Eco Design Consultants are proud to be at the forefront of the Passivhaus Industry in the UK, with 15 years of experience, and many certified, new build, and retrofit Passivhaus’s. We are proud Patron members of the Passivhaus Trust, as well as active members of the International Passivhaus Institute and AECB.