As Passivhaus Open Days return for another year, we give you the opportunity to hear our interview with Dr Wolfgang Feist from 2012.

Interview with Dr Wolfgang Feist

In the 70s, Dr Feist was working on how to meet the growing demand for energy in the world and found there was huge potential to use energy more efficiently rather than produce more energy. The International Passive House Institute is a research facility that influences construction by showing industry and government what can be done, helping to bring improved components to the market place, and helping affiliate organisations around the world to gain members, to gain knowledge and to make that knowledge available.

The Passivhaus approach addresses financial and environmental issues

The cost of energy has increased to the point that a lot of people now have problems paying their heating bills.

More than 80% of the energy being used in the UK, in the EU, and worldwide comes from fossil fuels. The consequences of this – emitting carbon dioxide into the earth’s atmosphere – means we really need to change the way we use energy and reduce our carbon footprint.

Passivhaus buildings are nearly zero energy buildings; their energy consumption is one tenth of that of conventional buildings. The energy you need is so low that it could be supplied by regional sources of renewable energy anywhere in the world, reducing the need to import and use fossil fuels. This is one of the reasons why the European Commission supports Passivhaus.

The Passivhaus approach delivers very high energy efficiency

The Passivhaus Institute produces tools for architects and engineers to make it easier for them to design such an energy efficient building.

By improving the building’s envelope you reduce the typical energy losses, so that you only need a very low amount of heat or cooling to keep the temperature comfortable.

The Passivhaus standard provides a universal design method for achieving a good indoor environment. Although a Passivhaus in Jakarta looks significantly different from one in Saint Petersburg (as local climate will inform the design), the method for designing these buildings is the same.

An improved building envelope has multiple benefits

As well as reducing the amount of energy you need, a higher quality building envelope:

• makes the building more comfortable
• will last longer
• improves the way we maintain the building in the future

The Passivhaus method doesn’t restrict the building style or type, and you can use any kind of material.

The Passivhaus Trust in the UK offer certification which provides assurance to buyers or sellers of Passivhaus buildings that they have been constructed properly and operate to the Passivhaus standard.

To design a low energy building first identify the services you really need

There are certain considerations that influence the energy balance of a Passivhaus building and so need to be factored into the design:

• Good insulation that avoids thermal bridging
• Airtightness
• Window quality
• Ventilation (required due to the air tightness of the building)

The Passivhaus standard isn’t just for new builds

Retrofitting of existing housing stock is harder. The key is to understand when it’s most efficient to make improvements. For example, if you have to do some maintenance to the roof, that’s the time to improve the insulation. You wouldn’t exchange a window just to save energy, you would upgrade an existing window at the end of its life. If you are going to improve a component then choose the best available because it will be 30-50 years until you do it again.

According to Dr Feist, most buildings in Europe that were built between the 60s and 80s are quite easy to refurbish. Older buildings, some of which may be listed, are a bit more difficult but on-going research means there are a lot of measures that can be taken nonetheless.

Passivhaus isn’t as expensive as you might think

Dr Feist explains cost and benefits of Passivhaus, using an example component. A Passivhaus window that is triple glazed and has a well-insulated frame and airtight window might cost £380 per square metre compared to £300 for a normal window. Although this is a little more expensive, the lifecycle cost of this investment gives a better return than investing the difference in other ways.

Non-financial incentives encourage adoption of the Passivhaus standard

Governments can help create a tolerant environment where innovation is accepted, including offering incentives. In Italy, for example, energy efficient builders are rewarded by being allowed to build on a bigger part of the land.

Dr Feist believes that distributing information on improving efficiency in new construction and in refurbishment of existing buildings is also an important role for governments.

The on-going challenge is to change habits within the construction industry

Scientifically it’s easy to improve energy efficiency, but the construction industry is very conservative. However, Dr Feist remarks that adoption of the Passivhaus standard continues apace because it’s not so different from what they have done in the past, adding, ”they can learn how to do it but they have to decide that they want to learn”.

Find out more

Visit the website of the Passivhaus Institute

Follow Dr Wolfgang Feist on Twitter

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