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Is Passivhaus Relevant to New Zealand?

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Is Passivhaus Relevant to New Zealand?

Posted 04 May '13 09:23 AM

Do you think Passivhaus is relevant in New Zealand?

Starting with the first certified one in New Zealand last year, there's growing interest in Passivhaus. I also hear a lot of questions and apprehension about the relevance to the NZ climate and culture. I interviewed an architect and Passivhaus expert on the topic recently and have summarised some of our discussion here:

Interested in people's thoughts.

Re: Is Passivhaus Relevant to New Zealand?

Posted 05 May '13 03:00 AM

I think Passivhaus and similar manifestations are great and one might suspect that the end game in the future of our new housing, bar any miracle new technology, would be pretty close to Passivehaus.

The two big themes or goals coming through in housing seem to me to be the demand for a consistent comfortable internal temperature and to have a low environmental impact.

The first has obvious benefits for health but also for productivity both in terms of economic and, what I would call "personal", productivity. We are also being increasingly motivated and, in-deed pressured, for better or worse, to live in a way that promotes health for ourselves and others so things like off-gasing or chimney smoke come into play.

Passivhaus has potentially quite low overall Greenhouse impact, a plus for me, particularly as an urban solution but many existing, simple NZ houses already achieve extremely well in this area and would be carbon-zero by some European definitions.

What I don't like is dogma, and there are those that promote Passivehaus as the only solution in an almost dogmatic way. Because we have mild weather conditions and short winters in the largest population areas, namely North Island coastal, there seem to be valid other options that achieve the goals stated.

I'm not sure, for example, that all houses need to have expensive MHRVs when they only need to be operating for four months of the year. This doesn't seem an efficient use of resources to me when other simple ventilation types might be fine.

Re: Is Passivhaus Relevant to New Zealand?

Posted 05 May '13 09:42 AM

I am not sure - if the passivhaus that has been featured here and has just been built near Raglan is an example of what is required to meet that standard then I for one would find it hard to live in - I would feel I was in a box with tiddly little windows, especially if it was in a rural setting like it is - all that extensive outside with no neighbours and little connection to it. The other thing that would interest me is the cost of a build like that - claiming that it is about 10% more than conventional is meaningless - what is conventional? It would be of benefit to those interested to say that the Raglan house cost say $300k then the exercise would have some relevance to consideration. I have a feeling that the cost of such builds would be beyond the reach of most new young home builders. Just my thoughts.

Re: Is Passivhaus Relevant to New Zealand?

Posted 06 May '13 04:28 AM

Here are a few interesting climate comparisons between Germany and New Zealand. What this tells me is that New Zealand and Germany Climates are nothing alike and a 100% PassiveHaus design isn’t right for NZ.

Germany annual average sunshine hours : Berlin: 1623 sunshine hours Hannover: 1501 sunshine hours Berlin average winter temperature 3 ?

New Zealand annual average sunshine hours: Auckland: 2007.5 sunshine hours Christchurch: 2142.2 sunshine hours Auckland average winter temperature 8?

Passivehaus is a good option for compromised building sites which don’t get good orientation to the sun might have restricted natural airflow and would otherwise be cold damp comprised locations to build a house. The Passivehaus idea is to rely on precise calculations and technology to save the day, creating healthy and comfortable environments to live in; disconnected from the natural environment . Germany has a very dense population, different climate type to NZ, is more protective of their remaining natural/ rural landscapes, the cultural is more urban and disconnected from the idea of what nature actually means or is and they also arguably build less than we do (which means when they do build, they will do it very well in a German High-Tec way). How they Germans build is always going to be very different to how the rest of the world builds and in particular New Zealand.

There are some very good technical details we can use and implement from the Passivehaus movement which will benefit NZ. However I have trouble digesting how it’s a perfect fit to NZ when it’s clearly not. NZ has great sunshine hours, 25% more than Germany in some places, NZ is warmer and we have more open space to build.

Re: Is Passivhaus Relevant to New Zealand?

Posted 07 May '13 05:56 AM

What about christchurchs average winter low of 1.7 or queenstown @ 0.1

Re: Is Passivhaus Relevant to New Zealand?

Posted 07 May '13 06:52 AM

Both Christchurch and Queenstown have plenty of sun shine hours which will more than adequately heat a house if designed and insulated correctly, the same can be said for the entire country. So I acknowledge it gets cold down there, but we can design for this. Why not design smart buildings which start engaging the NZ environment, rather than using imported design models which ultimately turn their backs on the local environment and natural resources. I’m not going to deny that Passivehaus have some very good principles and thermal strategies, - because they really do and we can learn a lot from this. However, if people are going to follow it like a dogma they are going to miss out on alot of New Zealand climate goodness, while looking out of some very small windows…..facing South.

Re: Is Passivhaus Relevant to New Zealand?

Posted 07 May '13 11:06 PM

I agree solarei. im instantly suspicious when I hear that part of becoming a Passivehaus has to include "The design software Passive House Planning Package (PHPP) is used in the design process" why cant they run the same series of tests on my tilt slab house designed by others for example.or the house pictured above.

Re: Is Passivhaus Relevant to New Zealand?

Posted 08 May '13 12:21 AM

Solarei, The Passive house standard is NOT specific for one climate or style of home/building. Buildings have been built to the Passive house standard all around the world and they aren't even all homes some are schools for example. An architect's design is certainly not redundant. How the occupants of the building wish to use the building are still a major factor in the building design of a passive house. It would be an interesting exercise to take one of your designs, (specific for it's particular location and it's occupants requirements) and get a PH designer to run it through the PHPP. I wonder what changes would be required to make the buildiing meet the Passive house standard? Or are you convinced that the building's year round energy use and comfort levels are satisfactory? Your photo example of a passive house is misleading Do you think the house featured in this link would meet NZ lifestyle?

Re: Is Passivhaus Relevant to New Zealand?

Posted 08 May '13 02:56 AM

The Ivanier house looks promising. I would be interested in visiting it to learn more. The house you have attached looks very beautiful, I suspect it’s British. How relevant it is to NZ, I’m unsure of.

Sure, appreciate you can still design good buildings using the Passive House Planning Package (PHPP) and many people are very happy with what they are given. And I think right fully so. Most designers and architects give minimal consideration to the thermal envelope and how air works (or air pressure for PH). That’s why most houses underperform temperature wise and healthwise in NZ. So I can see the attraction to Passivhaus. But be where, there are both academics and big business pushing this, primarily German based. Basically because we don’t have anything better on a large accessible scale, PH has ‘seized the day’.

The issue I have with Passivhaus is it’s a design dogma which rejects any design consideration of the climate e.g., sunlight, prevailing winds, micro climate conditions and sometimes context. This isn’t good for NZ or New Zealanders; we are a country of the land. There’s an emotional and physical connection we have with our environment. When we get overseas, especially in the super industrialised countries you see how these connections are lost. For PH it really doesn’t matter which the way the house sits on site, faces south, east, west or north, how many sunshine hours a site receives, or which way the winds blow during the seasons. PH doesn’t consider this at all. It doesn’t register in the calculation check list. The climate design is obsolete.

For me this goes against the entire premise of sustainability and environmental design and is largely why we are in a mess today. Houses/ buildings have been built to resist the climate and that’s why we require machines to heat them, cool them and expensive materials to insulate them. This all started to happen around the 1900’s with the invention of modern architecture, invention of electricity and invention of air conditioning. Prior to then, architects designed for climate. We had too. For the last 35 years there’s been a slow move back to more climate engaging design which uses the environment to heat and cool (smart buildings) ultimately reducing the dependency on machines and super High-Tec products. Passivhaus is High-Tec building and when you peel back the layers it’s the same old technology based buildings resisting the environment.

Everything we need to heat and cool buildings while making them healthy and comfortable we can get from the New Zealand environment by designing climate engaging buildings (smart buildings). We can do it more economically as well. We have more sunshine hours than Germany and live in a warmer climate. This alone makes the PHPP redundant and doesn’t justify the foot hold they have established. The climate science doesn’t stack up…..there isn’t any.

I will live some kudos to PH though, I think there is a need for these houses in NZ as not all sites are ideal for building climate engaging houses, and this is when PH can really come into play. PH houses are compromised solutions for compromised situations. Yes, I’m sure there would be some good benefits I could learn from a PHPP practitioner.

Re: Is Passivhaus Relevant to New Zealand?

Posted 08 May '13 03:13 AM

I have lived in PH houses in Germany and, after being a real advocate, I think the approach has to be filtered into an NZ context as ee enjoy a more temperate climate and generally have more constant solar gain. I think kiwi's are also used to a 'fresher' air quality, sounds funny but the sealed up houses in Germany I have lived in are quite claustrophobic.

Just my 2 cents...


A couple of clarifications

Posted 14 May '13 04:48 PM

Interesting discussion... and hope those participating have managed to find time to listen to the interview too, there is lots covered there.

I think a few of things need clarifying -

PHPP is a design tool and can be used on any building whether it will be Passivhaus Certified or not. It allows analysis of energy consumption and indoor comfort at any stage of a project and importantly it is *accurate* and has 20 years plus track record of comparison with real world results. There is no other design tool on the market that offers this. This is why PH Certification requires the use of PHPP so there is a baseline standard for projects to be compared on and it is known to be accurate. (it's only part of the certification process though and in some cases has been done for certification process after the building design and construction has been completed although this is not recommended!!)

Passivhaus DOES NOT "reject any design consideration of the climate e.g., sunlight, prevailing winds, micro climate conditions and sometimes context." Sunlight, sunshine hours, orientation, etc all all absolutely key for Passivhaus, it is not a one-size-fits-all it is a *performance standard*. How the performance requirements are met will always be completely specific to the actual local climate of the project. This varies between different parts of England and most certainly is different between Germany, the UK and NZ... and between different local climates of NZ (of which there are far more than the 3 that Building Codes indicate!) Climate design is most definitely NOT obsolete, it is absolutely CENTRAL!

Other design considerations such as the emotional and physical connection to the land are outside the remit of Passivhaus design / certification (quite rightly I would say), however, these are why it is best to involve an architect or designer who can respond to these aspects along with other cultural and personal aspects of any design project.

Passivhaus is not a "High-Tec" method of designing or building. Passivhaus buildings are designed to optimise building fabric performance, solar heat gains AND internal heat gains (ie from occupant uses) and reduce reliance on "high-tec" fixes. - In a domestic house, the inclusion of mechanical ventilation might seem "high-tec" compared to using all natural ventilation, however, the reduced reliance on heating balances this out so it is really no more or less "high-tec" than usual. - In non-domestic buildings, Passivhaus is a "low-tec" approach compared to standard. Passivhaus Certificated schools we have designed (and are loved by the users and operating very well) have considerable less mechanical and electrical equipment than standard schools (including ones we previously designed!) The same applies to other types of buildings.

Re: A couple of clarifications Passive Houses

Posted 15 May '13 12:29 AM

Thanks Elrond, Excellent explanation You have explained a lot better than I did, the point I was trying to make with Solarei

Re: A couple of clarifications Passive Houses

Posted 15 May '13 05:31 AM

I don’t think there’s any question of how effective PH is at monitoring energy performance or regulating interior comfort or its track record in other countries.

The PH design approach uses climate data to regulate the building’s interior environment by analysing solar gain loads, types of materials, seasonal/country/ regional temperature differences etc. This information is then used to design the performance of the house.

There are definitely positive applications of this design approach, some of it is relative to NZ and the other I’m unsure of.

My view is that this approach mostly neglects to physically integrate the house design with its context and environment. The design floor plan can be anything/ oriented anyway. Climate design is allowed for as ‘performance standards’, indicators used to calibrate the design. This is acceptable in other countries like the UK and Germany, their culture and climate is fundamentally different.

The New Zealand climate is perfectly suited for passive solar gain given our seasonal latitude to the sun and mild climate conditions. I guess simply this is not what PH is about, it kind of really bugs me and brings into question how relevant this model is to NZ.

HOMESTAR set out by the New Zealand Green Building Council (NZGBC) makes a significant step in recognising the importance of designing to the New Zealand Climate, specific site conditions and particularly passive solar gain. Our neighbours across the ditch (AGBC) who are well ahead of NZ in regards to environmental design make a clear emphasis on the importance of Passive Solar (amongst other key areas). Performance Standards as you have pointed out are how PH addresses these issues; - the HOMESTAR and PH approaches are quite different.

One approach engages through physical use and interactive design, the other regulates, calibrates and seals.

Re: A couple of clarifications Passive Houses

Posted 15 May '13 09:54 PM

Nikoftime - no worries & thanks.

Solarei - I think your criticism that PH "mostly neglects to physically integrate the house design with its context and environment" is probably quite true on a number of buildings, but this is true on both PH and non-PH buildings... and dare I say it, equally true on a Passive Solar Design also. These are, as I mentioned earlier, outside the remit of the PH design / certification process (taking "environment to mean wider context, landscape etc rather than local climate conditions) and really depend on a good architect or designer being involved.

I would say if you look at the Raglan PH and think it really doesn't belong in the NZ landscape, that the reason for this is the clients are a Dutch couple who wanted something quite specific for their needs. MOAA Architects seem to have done a very good job of designing a PH that meets those specific needs and their budget .

I also appreciate that when you look at many PH buildings they *appear* as if they are not noticeably orientated for best solar gain, particularly when compared to a Passive Solar Design building - however, I can reassure you that it is absolutely crucial to get the solar orientation right for PH design, with the exception of fairly large buildings or buildings with high occupancy loads that are much more tolerant when it comes to orientation for a variety of reasons. A colleague of mine did an exercise where he ran the design of his non-PH house (built several years ago) through PHPP and examined what changes he would need to make to enable the house to reach PH energy and comfort standards. It turned out that the biggest factor was the orientation - considerably more so than increasing insulation, increasing airtightness or introducing heat recovery ventilation.

One of the difference between PH and PSD is that PH optimises solar gain whereas PSD maximises solar gain (to put it crudely!) So when you look at a PSD building the solar orientation is extremely obvious whereas when you look at a PH building the solar orientation is more subtle and nuanced, but it is still there at the centre of the design.

I'm not sure why you would consider climate design acceptable in Germany and the UK but not in NZ? Clearly PSD is also all about calibrating the design for the local climate after all! The purpose of architecture could be said to be to modify the climate to provide a suitably comfortable interior space for inhabitation and use.

Yes there are some cultural differences between Germany, the UK and NZ... as a Kiwi in the UK I am accutely aware of this! :-) However, many aspects of culture are shared and we shouldn't pretend that NZ is exceptionally unique and special somehow! :-) Brits love indoor / outdoor flow also and love keeping windows and doors open whenever the weather is fine! They don't have such a magnificant landcsape to see outside in most cases though!

I agree that the NZ climate is perfectly suited for PSD in many parts of it and for this reason it is also perfectly suited for PH design! The only difference is that in many parts where it isn't suitable for PSD it is still suitable for PH design.

You seem to misunderstand what I mean by a performance standard. PH sets a standard for indoor conditions and energy consumption - these apply anywhere in the world and how these standards are met are entirely dependent on where the building is.

You imply that PH seals the building, this is partially correct. PH insists that the fabric of the building must be airtight to prevent unwanted moisture in the fabric, unwanted heat loss through the fabric, unwanted draughts inside the building and unwanted condensation and mould. However, how the fabric is made airtight is not prescribed. For example, we use breathable (vapour permeable) and hygroscopic materials which we believe are best for human health and best for the environment. Other architects maye approach it differently. Windows and doors can of course be opened anyti

Re: A couple of clarifications Passive Houses

Posted 16 May '13 10:19 AM

Just got off a Skype call with Jon from ehaus, NZ's own Passivhaus experts. So look out for a followup interview on Home Style Green shortly!

Re: A couple of clarifications Passive Houses

Posted 16 May '13 11:14 AM

Thanks Elrond. Appreciate your explanation.

Its really interesting to hear what you say and the PH approach. I really feel we are poles apart in our thinking.

Let’s define what PH is, I think this will help: PH is about designing buildings/ houses with efficient thermal envelopes, minimal/ or no thermal bridging, regulated air control and air pressure and making climate adjustments for regions/ countries and occupants. Following the PH method you can achieve low energy use and comfortable internal temperatures in most temperate climates- right?

My thoughts are there’s tremendous climate differences between NZ and Europe (please refer to the data below) and there are many cultural differences, beyond what you’re saying. Sure NZ is a Western culture. However Europe has significantly larger populations (hundreds of millions) with limited access to affordable land and resources. NZ is not like this (although this is changing). The reason why PH works in these countries is because it was developed for their climate types under unique cultural conditions. These countries do not have the same opportunities as NZ does given restricted climate conditions and cultural restrictions for building. All PH is doing is transplanting an advanced building system on the other side of the world and making it work. Because the math stacks up doesn’t make it the correct fit. This type of thinking is no different to imperialism, one advanced culture dominating the inferior and over the past one hundred years this has accelerated all over the architectural world. It’s hard to work out if a house or building has been designed for the UK, DUBAI, BANGKOK or NZ. Architects, Engineers parachute in from different countries, work out there calculations and designs and then fly out. I don’t think PH is any different; even though the intentions might be good.

My position is that buildings and houses can be designed in such a way to reduce or eliminate the need for machines and dependency on High-Tec materials. It all starts with the local site and climate. (Don’t agree with your comments in saying PH is not High-Tec; - It uses sophisticated calculations methods combined with advanced materials and construction methods to produce its houses).

New Zealand has a unique set of climate conditions (like any other country or region) which the country is still working out how to deal with. These climate conditions need to be carefully considered to produce smart climate engaging designs- typically referred to as Vernacular architecture. PH is not about this.

NZ needs to develop its own approach to how it produces low energy warm comfortable houses if it is ever to make any progress. We can learn certain lessons from PH ( mainly through the thermal envelope), but ultimately and how ever its sold to clients, its always going be an overseas based model made to fit NZ with many limitations.

Germany annual average sunshine hours : Berlin: 1623 sunshine hours Hannover: 1501 sunshine hours Berlin average winter temperature 3 ?

New Zealand annual average sunshine hours: Auckland: 2007.5 sunshine hours Christchurch: 2142.2 sunshine hours Auckland average winter temperature 8?

Re: A couple of clarifications Passive Houses

Posted 16 May '13 11:53 AM

Its all about designing a healthy indoor environment. It has nothing to do with the outside world. If anything it easier to reach in new zealand with warmer temps and more sunlight.

Let heat in through windows or heating. Store heat in thermal mass. Keep heat in with airtight and thermal envelope.

The local weather determines what size windows, eaves, thermal mass and insulation.

Solarei may I ask what the energy use of your house is. And do you keep it above 21/17 deg year round

Re: A couple of clarifications Passive Houses

Posted 17 May '13 02:55 AM

Hi Nzsparks; Yeah well I guess that’s my issue then, ‘it has nothing to do with the outside world’. I can’t digest that....not for NZ anyway.

The attached 240m2 house achieved, 3200 Kwh for one year in 2011. It dropped to 17 degrees mid-winter 5 am, 3pm it was at 24 degrees.

The house is designed for optimised passive solar gain and passive ventilation. By passive ventilation I mean you can open the windows allowing fresh air to enter when you like( through a designed air strategy). It has a central clerestory which functions as a climate chimney over summer (stack effect).

The house is located in central North Waikato, has above code insulation for walls, ceilings and slab. Uses regular double glazed glass and was built for $2000per/m2.

I’d be interest to know what the PH statistics are like.

Re: A couple of clarifications Passive Houses

Posted 17 May '13 09:24 AM

Ooops, looks like my last post got cut short.

Solarei - Actually I disagree, I think you and I have very similar feelings about architecture in NZ and are not poles apart at all. I'm not sure you understand the Passivhaus approach yet though so it might seem like we are poles apart.

There's no conflict between vernacular architecture and PH - on the contrary PH traces its legacy to vernacular architecture in diverse locations around the globe, including places as different as Scandinavia and China.

Congratulations on the North Waikato house - it sounds like it is lovely and uses considerably less energy than typical NZ houses and sounds much more comfortable than typical NZ houses also. I imagine you have very satisfied clients too.

Re: A couple of clarifications Passive Houses

Posted 17 May '13 10:53 AM

Here's an example of a PH being designed on a Greek Island (Ie with plenty of sunshine!) in the local vernacular and using full Bioclimatic design principles -

Re: A couple of clarifications Passive Houses

Posted 17 May '13 12:37 PM

And a Passivhaus I'm designing for a rural location in the north of the uk, which due to its connection with the landscape is heavily reliant on orientation for passive solar gain.

Re: A couple of clarifications Passive Houses

Posted 19 May '13 02:31 AM

Hi Elrond, Thanks. The Greek Island project looks promising and makes good sense. The clients had strong ideas about ‘bioclimatic design’ which they and their architect have worked it through the design- great to see.

Hi PTA, The Burrows also looks like a fun project, architecturally and PH wise. You must be looking forward to its construction.

Re: A couple of clarifications Passive Houses

Posted 28 May '13 10:00 AM

Hi ALL, I recently was asked to explain the difference between PASSIVE SOLAR and PASSIVE HOUSE. I don’t deny that I am bias and bat for a different team ;-). I give due respects to PASSIVE HOUSE, as the opposing team. I haven’t sent this out yet, Interested in knowing what people think. This is what I came up with:

Passive solar

New Zealand has the perfect seasonal latitude differences to the sun for passive solar gain. It’s part of our vernacular architecture. A passive solar house uses the local climate for natural heating and cooling. Floor plans utilise good northern orientation following the seasonal sun path in the sky. This allows low angled winter sunlight to be beam deep into a house if designed correctly. We can use this sunlight (radiant energy) to passively heat thermal mass floors and walls. This then releases natural warmth into the house when external temperatures drop. During summer, sun angles are high in the sky and we design to reduce direct sunlight by correct eaves design, window sizing and locations. This prevents overheating. We also design for natural ventilation by using a principle called stack effect, this works on hot air rising and creates a natural exhausting system. Through this we can achieve an energy efficient house with a comfortable interior environment in tune with its local environment.

Passive house

Passive house principles where developed in Germany and are now found throughout Europe and recently New Zealand. Its worth mentioning that the passive house principles where born out of a different climate type to NZ (reduced annual sunshine hours) and equally different cultural conditions (larger populations with limited access to affordable land). The houses can be oriented in any direction, north, south, east or west. They do not necessarily rely on sunlight for heating, although this can contribute. The houses do not require additional thermal mass and can be constructed from any material e.g. Timber or Concrete. Tightly sealed thermal envelopes minimise thermal bridging, tightly air sealed walls prevent air from escaping to the outside (heat lose) and controlled mechanical ventilation regulates and achieves comfortable internal temperatures. The houses achieve good energy efficiency and a comfortable interior environment.

Re: A couple of clarifications Passive Houses

Posted 28 May '13 10:35 AM

I think one does not exclude the other regardless of the climate. The correct orientation, eaves, shading, a good thermal envelope with insulated windows and air tightness is important for passive solar and passive houses. The best and easy thing against over heating in any type of house are external shutters as used in southern Europe to keep the heat out. Tonight is veeery cold all over NZ and without an airtight envelope and insulated windows it would be very uncomfortable in any house including a passive solar house. I know as I lived in one. At the end of the day the windows are only opened in nice and warm weather, whether it is a passive house or passive solar house or similar. New Zealand is warmer than Germany with more sun hours but the Winters in New Zealand are quite long too, often very wet and little sun for days. There are passive houses in Germany with very large windows and the Raglan one is not a very good example as it is just a box and it give a totally wrong impression about passive houses. If you look on the web you find many passive houses in Europe with large openable windows, a great indoor outdoor flow for summer, but very warm when the weather is cold. I think this unique climate thing in NZ is more a wishful thinking than reality. There are many places with similar climate along the coastlines of our planet.

Re: A couple of clarifications Passive Houses

Posted 28 May '13 11:13 AM

Next time I have some time to kill. I'll give you a list of 100 cities from around the world with a climate close to our 4 biggest cities. How about passive house is a standard to achieve a healthy house. Passive solar is a design principle to achieve a healthy house. A house can be a passive house built using a passive solar design.
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