What is a “passive house”?

No, it’s not a lazy building.

And despite many not-so-funny jokes you can do with its name, it is something that is worth investigating.

In fact, it is an exciting idea that is still niche in the UK, but already widespread in Germany where it was born about 20 years ago. It’s an original concept that is in truth very simple, but still revolutionary in cities that waste an important percentage of their energy because of poor building insulation.

Passivhaus technology, that’s the name of the certification required to call a building a “passive house”, is about designing and constructing houses with the maximum level of insulation. To do so, there’s no need for expensive materials. The vast majority of the materials used to build a passive house are actually conventional and relatively cheap: bricks, concretes, polystyrene and timber. What really makes the difference is the building’s design. In simple terms, it’s not about what you do, it’s about how you do it.

To learn more about this technology I met Dr Wolfgang Feist, Director of the Passivhaus Institut of Darmstadt in Germany.

As Dr Feist says, if you live in a passive house your gas bill will be dramatically reduced.Consuming less gas has an economic advantage, however it is necessary to compare the production costs of this kind of building with the cost of a conventional one. I asked Dr Feist about this:

That said, it is important to understand that in building a new house or retrofitting an old one, the payback time shouldn’t be considered an absolute factor. In fact, it is not only a matter of saving money. With climate goals imposing strict rules for the coming years, a high energy standard building will be more valuable on the market.

Hence, building a passive house is a wise idea from several points of view. But what has prevented this technology from spreading faster in the UK and in the rest of Europe? First, achieving the Passivehaus Certification is not simple. Alasdair Donn, Energy Solution Engineer at Willmott Dixon, explains why:

Donn explains that in the UK there are several companies that have already succeeded to build passive houses. At the moment,there is a lack of know how  in the country, rather than a lack of materials or economic potential. But according to him, this will get better in the next years “since the few projects that are being completed could act as a catalyst to grow the demand for passive houses as it happened in Germany.”

Despite having serious energy consumption problems in the oldest and poorest neighbourhoods, London already has a fair number of new, energy efficient buildings. The latest project for a Passivhaus residential scheme will be completed in Camden, where Willmott Dixon will participate as the major contractor in constructing 52 new apartments. The investment of £10 million is part of Camden’s Community Investment Programme.

Alaisdar Donn believes that the passive house business model is a winning bet: “A possible help from the government, in terms of policies, would be certainly good, but even without it we can predict a successful future for this industry in the UK.”

By Lou

Featured image courtesy of


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