Posts Tagged ‘Passive house’

PassivHaus: the devil is in the detail

07/10/2011

The PassivHaus concept is quite a simple one: create an airtight, super-insulated structure, install mechanical ventilation with heat recovery, address thermal bridging, and find yourself with a building that can essentially be heated by a hairdryer. However, as with most things, the devil is in the detail…

Here, I take a look at the following questions:

What does a PassivHaus look like?

PassivHaus is really a design and build process, as opposed to a particular style of architecture. Whilst we may have preconceived ideas of a PassivHaus-certified building’s aesthetics, it could (at least in theory) look pretty much like anything – especially given that existing buildings can be retrofitted to PassivHaus standard.

100 Princedale Rd, Paul Davis + Partners

This was done at 100 Princedale Road – a Victorian house in a London conservation area – by Paul Davis + Partners and contractor Philip Proffit of Ryder Strategies Europe Ltd. This house was the first of its kind in the UK to achieve PassivHaus accreditation, meeting its target to reduce carbon emissions by 80%. (Granted, with the subject of the retrofit starting out as a drafty, four-story old house, there was plenty of scope for improvement.) In other words, a passive house can be anything from a large, new office building to a centuries-old, traditional house. Below are some examples:

Single-family residence in Brooklyn, NYC | Gregory Duncan

Eurogate Sozialbau, Vienna – Europe’s largest PassivHaus settlement? | Tiger46 on Flickr

Passive house office building in Austria | Tõnu Mauring

What does a PassivHaus cost?

The Footprint article on the Princedale Road Retrofit for the Future project includes an interesting breakdown of the cost / payback time / bills before and after completion, making a comparison between refurbishing to PassivHaus or Decent Homes criteria. The Green Building Store, in conjunction with Building magazine, has also provided a breakdown of costs for the Denby Dale PassivHaus in West Yorkshire.

What about air quality?

The more passive (or other enclosed, airtight and sealed) houses we construct, the more important it is that we keep monitoring and assessing the quality of the air circulated in these buildings. Are we avoiding moisture build-up? Is the air too dry? Is there enough of it? Will we see a concentration of emissions inside these buildings, over time, from the building materials used? What are the potential positive/negative effects on occupants’ health and well-being? Housebuilder’s Bible author Mark Brinkley experiments with air quality and CO2 levels in this House 2.0 blog post, relating his findings to PassivHaus standards.

To ensure a good level of fresh air supply, most passive houses are ventilated and heated by mechanical ventilation with heat recovery (MVHR). Heat from the warm air that is being extracted is passed to the incoming fresh air through a heat exchanger – with the result that heat loss is minimised and heating costs are reduced. Ducting is an integral part of this: “Marion Baeli, the architect on the [Princedale Road] project, stressed that in a retrofit with MVHR, the coordination of ductwork requires considerable design attention, and should be integrated right from the start.” (Footprint)

Airflex Pro suspended ceiling ductwork installation (Airflow Developments on ESI.info)

Which products are used in a PassivHaus?

The PassivHaus Institut provides a list of certified building components, products and systems suitable for use in PassivHaus construction. Presumably, as this concept gains popularity and awareness, the list will grow. We have already looked at ventilation. Other important components are energy-efficient windows, airtight seals and thermal insulation.

But of course, a component is only as good as its installation. As well as architects who know how to design a successful PassivHaus, and manufacturers who can make products suitable for this type of construction, we need contractors with the right skills and experience. (PassiveHouse Builders, Passivhaus/LCC, Passive Development and Viking House are some of the firms I have come across.)

Project Green Home, Palo Alto | Mark Hogan

What is it like to live in a PassivHaus?

Bill Butcher, the construction manager of the Denby Dale house, kept a 17-instalment diary during the building process. But what happens post-occupancy? How does the building perform, and how does it shape the lives and behaviours of its occupants? In a separate post, I have taken a closer look at the realities of living in a passive house.

What is the next big thing after PassivHaus?

In the absence of a unified, international environmental standard for buildings, there is a certain amount of ‘competition’ between the different accreditations. There is no shortage of acronyms to choose from, and there are almost as many opinions on which accreditation makes the most sense as there are design-and-build professionals. (For a sensible take on PassivHaus vs the Code for Sustainable Homes, see “The Bout of the Decade” by Sustainable Homes.)

Andrew Holt heads the practice Architectopia in Norway, and also runs a course on sustainable architecture. He has worked extensively on PassivHaus developments. In an Arkitektnytt.no article, he talks about what the next big thing after PassivHaus might be. Mentioning BREEAM, zero-emission housing and “plus houses”, Andrew emphasises the importance of tailoring the standard to the individual project, using different tools to come up with a package that is fit for purpose. He comes to a refreshing conclusion (my translation):

What follows ‘after’ the PassivHaus standard should be a variety of different possibilities, so that our ambitions are based increasingly on the individual project and its local climate and conditions. This would facilitate greater innovation, creativity and cross-disciplinary co-operation. This approach demands a high level of competence within the project team.

An understanding of what the PassivHaus standard is, is a prerequisite for high-quality construction within the energy-efficiency sector. An understanding of what the PassivHaus standard isn’t, is a prerequisite for moving forwards.

PassivHaus office in Langenhart | Train.bird on Flickr

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How to design a Passive House

07/10/2011

If you are looking to get started in Passive House design, you probably already understand the concept, but if not, first take a look at The Realities of Living in a Passive House, where the theory and the reality are explored.

Below are some more useful links and resources for Passive House design, ranging from the planning and design side, to the fully realised, bricks-and-mortar (or should that be insulation-and-seals?) side of things.

The concept
• Mark Siddall of Devereux Architects explains how simple the PassivHaus concept is and why it ‘is arguably THE low energy, low carbon design standard’.

A certified Passivhaus and part of the Welsh Future Homes Project

Specification
BRE provides a simple comparison between the outline specification of the PassivHaus standard and UK new-build common practice. Notice the wide gap.
Passive House Planning Package – a clearly structured design tool that can be used directly by architects and designers.
• The Passive house Construction Check List from the German PassivHaus institute makes it easier to reach certified passive house standards by listing the most important steps in the process, and particularly draw the attention to the quality control process that must accompany the passive house construction process.

Passive house conference 2006

Certification
The standards are voluntary but rigorous.
• BRE oversees the PCScheme (PassivHaus Certification for Certified Designers and Consultants).
• Three key tests are carried out- the first being an initial energy calculation carried out in the Passive House Planning Package by a passive house designer, resulting in a passive house assessment report.
A blower door test in the US, sometimes referred to as pressure testing / air permeability testing in the UK. (more info from a UK provider of PH testing services)
• The final quality checks by a qualified PH Certifier, after which the project is certified as an approved passive house.

Hudson Passive House image courtesy of BASF. Neopor® insulation used in Hudson Passive House by Dennis Wedlick Architect LLC

Organisations
• The Passive House Institute in Darmstadt, Germany, founded by PassivHaus co-originator Professor Wolfgang Feist.
• BRE UK Passive House hub
International Passive House Association.
Passivhaus UK, part of the BRE.

Refurbished with passive house components, kindergarten in Estonia Valga

Other resources
The Passive House magazine
PassiPedia is a website dedicated to PH definitions, technical details, knowledge, news, performance stats, residents’ experiences etc.
Certified Passive house designer course

USACE delivers 106 environmentally sustainable townhouses to Ansbach military community

UK Projects
• Y Foel, passive house in Wales
The Crossway Passivhaus, by Richard Hawkes and featured on Grand Designs. See also this article by the certifier.
• Tygh-Na-Cladach, the UKs first affordable passive housing, designed by Professor Gokay Deveci. Again, certified by SPHC.
• The Lime House at The Works, Ebbw Vale. A certified Passivhaus and part of the Welsh Future Homes Project. Further details on the BRE website

The realities of living in a PassivHaus

07/02/2011

Thermal image of a PassiveHouse (Young Germany)

Once the scaffolding is down and the blower door test has been passed, what is it actually like to live in a PassivHaus? How does it feel to occupy a house that is kept warm using only your own body heat; a house that is completely airtight and needs no conventional heating system? How does it change your behaviour, needs and habits?

PassiveHouse as a concept

The concept of the passive house (or PassivHaus for the internationalists amongst us) is becoming increasingly well known amongst British architects, contractors, developers and clients. It has moved from being yet another forward-thinking construction method that is adopted in mainland Europe but largely ignored in this country, to being championed by a number of UK built environment professionals.

Information abounds when it comes to PassivHaus certification requirements, test results, design detailing, building physics and heat capacities. The Passipedia website is a good resource in this respect. It also gives an interesting historical review of  passive houses from the past. Did you know, for example, that Fridtjof Nansen’s 1883 polar exploration ship Fram functioned like a PassivHaus? Nansen wrote:

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