Very Low Carbon Habitat

The Passive House idea promises a low-carbon lifestyle that does not harm the environment, and the fact that it is gaining traction around the world shows that such claims are far from being just platitudes.

It’s hard to believe, but the Passive House concept of energy-efficient construction has been gaining traction all around the world since it was first developed in 1990.

There are already approximately 30,000 structures that are classified as matching the essential standards, covering a million square metres of space. That may not be much in the grand picture of the global built environment, but it demonstrates the constant development in the construction of certified Passive House structures.

The millionth-metre record was achieved last year with approval of a detached house in Santa Cruz, California, in the United States. The Midori Haus, as it is known, earned its accreditation from the Passive House Institute (PHI) in Darmstadt, Germany, in December 2014. This property’s symbolic significance was recognised by the institute with the granting of a special certificate, which you may term a commemorative one.

Originally built in 1922, the Midori Haus is a three-bedroom, two-bathroom single-storey home. It was renovated in 2012 to the Passive House Standard. Even though the house was renovated, it still had many of its original features, such as the original foundation, floor, framing, porch, and built-in furnishings. Since the project was done, the energy consumption has been tracked, and the utility bills show a reduction of 80 percent in energy consumption.

Conventional Boilers

California’s climate, of course, is somewhat removed from that of Central and Northern Europe, where the Passive House concept was first devised, but it is a concept that has been tailored to – and been realised in – a variety of different climates in the 25 years since the first building tested out the principles. These days, Passive House buildings are to be found on almost every continent and in practically every temperature zone.

The majority of Passive House constructions – not just residential ones – are found in Central Europe, and the actual number of these structures may be significantly larger than the PHI estimates.

That’s because for one thing, it exists to widely distribute its research into the notion and methodology for putting it in practise, for another certification is voluntary. Consequently, the existence of Passive House buildings may be significantly more ubiquitous than even its founders recognise.

Zeno Bastian, the PHI’s director of building certification, said, “In principle, anyone can build a passive house.” “What matters is compliance with the clearly defined criteria for energy consumption. The climate has a significant impact on how this is achieved. In Central Europe the most critical measures include thermal bridge free construction, an airtight building envelope, a ventilation system with heat recovery, triple-glazed windows, and superior thermal insulation.

“The primary purpose of certification is quality assurance. With this internationally known mark, building owners are safe in the knowledge that the intended savings for heating expenses and added benefits of a Passive House will truly be realised.”

The Passive House concept – or ‘passivhaus’ to give its European feel – was created by Professors Bo Adamson of Sweden and Dr Wolfgang Feist of Germany, with the ‘prototype’ constructed in Darmstadt. Known as Europe’s first multi-family residence to attain a verified heating energy use < 12kWh/year, the Kranichstein Passive House (m2a).

Since then, the concept has taken root with Passive House constructions created in every European country, with Australia, China, Japan, Canada, the USA, and South America joining in to put the concept through its paces. Apparently, there’s even a research facility in Antarctica designed to the Passive House standard, according to the PHI.

These days, when branding is King – or at least courtier – it is important to note that Passive House is not a brand, nor is it linked to any specific type of construction; both are important points in maintaining the flexibility and adaptability of the principles, as much as its ‘open source’ nature, whereby anybody can access the research of the PHI and its sister bodies around the world, and work on its own enhancements to the concept.

That undoubtedly helps to explain its rising worldwide appeal and the diversity of projects to which it has been used. To date, according to the PHI, the largest building built to the Passive House criteria is an office tower in Vienna, Austria. Nearly 21,000 square metres of the RHW.2 building can be put to good use. Conversely, the smallest certified Passive House is a structure near Rennes, France, which has a floor space of just 11 square metres.

And don’t forget about the Bahnstadt district in Heidelberg, which is hailed as the largest Passive House neighbourhood in the world! It won the 2014 Passive House Award for “exemplary nature” at the International Passive House Conference last year.

An award plaque currently adorns the district’s Schetzinger Terrasse kindergarten where passers-by can see this reminder of the area’s international prominence.

“The award displays strikingly the pioneering spirit demonstrated by the world’s largest Passive House neighbourhood,” remarked Heidelberg’s mayor, Dr Eckart Würzner during the plaque’s ceremonial installation last year. “The Bahnstadt district is gaining ever more attention internationally and is visibly asserting itself as one of the most innovative urban development projects of our time.

It is a source of pride for us that our newest city area exemplifies what is achievable when current technological opportunities are wisely utilised.”

According to Dr Feist, who is director of the PHI in Germany, the district more or less discloses a perspective of future urban living. A growing number of countries are adopting high energy performance construction methods, according to him. However, this is the first time a city district has been designed to the Passive House Standard. In this way, the city of Heidelberg is presenting a template for the future. The European Buildings directive specifies that so-called Nearly Zero Energy Buildings are to become the norm by 2021. With the Passive House Standard, Bahnstadt is already fulfilling these requirements.”

Internal Insulation

The Passive House movement is gaining traction in the United Kingdom, but the country’s uptake has lagged behind that of the continent, owing in part to the development of ecotowns and the Code for Sustainable Homes, which served as a guide for the government’s zero-carbon goals. Despite this, the UK has now officially joined the worldwide Passive House movement.

Hastoe Housing, for instance, constructed its first Passive House development in Wimbish. The results of a two-year examination of the 14 “exemplar” homes were released by the organisation in October of last year. The study, funded by the University of East Anglia and the Technology Strategy Board, gave a good result for Hastoe – that the homes had operated as anticipated and delivered considerably cheaper heating expenditures for the inhabitants.

Considering that it was Hastoe’s first Passivhaus project, the architect’s first Passivhaus design project, and the contractor’s first Passivhaus construction project, these findings are remarkable and demonstrate that Passivhaus provides a viable and successful route to low-energy living, the evaluation report stated.

Sulgrave Gardens in Brook Green, Shepherds Bush, London, is an example of Octavia Housing’s Passive House design in an urban area. It was hoped that the 30-unit mixed-tenure project would demonstrate that the idea could work well in densely populated areas like those found in the United Kingdom.

In addition to the normal planning and local context issues, the site is situated between two conservation areas, which posed additional challenges for Octavia and her team. Because of this, as well as the aim to construct a massive mixed-tenure system guided by Passivhaus principles, “new dimensions of innovation were required,” the organisation stated.

Low carbon living is critical to help turn the tide of climate change, and that’s precisely why Passive House is gaining traction, but there’s another key reason too – and that’s in the wallets of the residents.

Perhaps it’s apt, then, to leave the last word on this to the concept’s originator, Dr Feist: “Passive House components allow building owners to save hard cash.”

Composition of a low-carbon lifestyle

On average, Passive Houses reduce energy use for space heating and cooling by up to 90 percent compared to “typical building stock,” and by over 75 percent when compared to new construction. They utilise less than 1.5 litres of oil or 1.5m3 of gas to heat one square metre of living space for a year, reported to be much less than ordinary ‘low energy’ houses

• Passive Houses utilise the sun, internal heat sources and heat recovery in such a way that make conventional heating systems obsolete, even during the coldest of winters. During warmer months, they make use of passive cooling strategies such as selective shading to keep them comfortably chilly

No matter how cold it gets outside, the temperature inside doesn’t change much from the air temperature inside. Heat may be kept in or kept out of a home with the use of energy-efficient windows and a well-designed building envelope that includes an insulated roof, floor slab, and exterior walls.

• A ventilation system discretely distributes regular fresh air, sustaining air quality without annoying draughts. Heat from exhaust air may be recovered and reused with the help of a very effective heat recovery device.

Last Updated on December 29, 2021


Author: Indra Gupta

Indra is an in-house writer with a love of Newcastle United and all things sustainable.

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