All posts by cora

Million Metres fundraise for Baring Head habitat restoration

General

CORA would encourage Wellingtonians to support the Friends of Baring Head who are fundraising through Million Metres Streams with the assistance to the Greater Wellington Regional Council. Their mission is to plant 5,000 native plants and trees along 550 metres of the Wainuiomata River in 2019.

This is the second year of a 10 year project to restore the entire river valley with native plants and trees including cabbage trees, harakeke, ngaio and toetoe. The funds raised will go towards the plants themselves, site-prep, planting and post-care.

Baring Head is a spectacular 284 hectare headland and river valley on the coast south of Wainuiomata, between Palliser Bay and Wellington Harbour. It’s a scenic reserve, managed by GWRC as part of the East Harbour Regional Park.

Friends of Baring Head supports GWRC in its stewardship of the area and the restoration of Baring Head.

“Baring Head is a special place” says Paula Warren, Chair of the Friends.  “That’s why the community helped find most of the money to buy it in 2010. Since then, the Friends have contributed significantly to a major ecological restoration programme. Already, visitors can enjoy the benefits of this work, but this is just the start.

“We have a grand vision to transform the property. This includes creating something similar to the original riverine forest. Million Metres, the generous support of donors and our volunteers will enable us to do this.”

Thanks to a generous donation from a local Wellington family, donations to the project are currently being doubled. To find out more and support the restoration of Baring Head please visit millionmetres.org.nz

 

The South Pacific Passive House Conference and Trade Show Christchurch, 04-05 March 2017

General

The Passive House Conference – personal impressions

As a lay person, attending the Passive House Conference in Christchurch was a daunting prospect. After all, the Passive House system relies heavily on data, modelling and real science (yes physics!), an approach which is hard for me to get my intuitive and non-scientific brain around. However, the weekend was fascinating and I came away feeling energized by the breadth of knowledge, experience and enthusiasm on display.

So that this blog post doesn’t turn into a snore fest, here are some brief impressions and standouts gained from the talks and from, well, just being with people who are passionate about raising the housing/construction bar.

The visit to a certified Passive House under construction in St Martins offered the physical experience of looking into what goes into making a house Passive. I guess it boils down to three elements; PH certified windows (the certified windows used in this house were produced by Thermadura in Mosgiel), a mechanical heat recovery unit and a well-insulated building envelope (prefabricated panels by Theca) designed to eliminate thermal breaks. Even though this house is still in the construction phase, talking to the owner, one could sense his excitement. Because the panels were constructed off-site, the shell of the house went up very quickly. (Post script, this house has just been certified Passive House+ – the first in the South Island.)

Passive house complete Passive house prelining

I only attended one day of the conference so I can’t comment on Saturday’s talks however the various speakers on the Sunday looked at the Passive House system from a variety of experiences. Andrew Michler in his talk, The Passive Insurgency, encouraged us to become Passive Jedis – to take the message of fabric first to the public. As he says, the stories behind these builds are exciting and energizing. His own story, building the first certified Passive House in Colorado (using basic materials with minimal toxicity in an area which has very harsh winters), is inspiring. However, he impressed upon us the urgency of this insurgency. Incrementalism is no longer an option if carbon emissions are to be reduced to a level that sustains life as we know it on this planet. Given that building/construction is the largest carbon producer in the world, it is important that buildings are built for longevity. It accounts for 40-50% of carbon emissions both in the construction phase and during occupation (building usage).

Enrico Bonilauri spoke of a Passive House EnerPhit (retrofitting an existing building to a slightly different standard) in Italy. Italians by and large do not see their houses as ‘cash cows’. Rather, the average Italian house changes ownership roughly every 50 years. That factor, coupled with an ability to deduct the cost of carbon emission remediation against income tax, made the masonry retrofit (built in 1962) of a “tough guy with weak ankles” (the structure was sitting on walls one brick thick) an economic proposition over the life of the building. The owners of this building will be able to claim roughly 100k euros in income tax deductions over the next ten years. This has made the baseline budget of 225k euros easier to swallow.

Enrico made the point that if you build or retrofit a house to a low standard, you are locking in energy inefficiency for decades to come.

Jessica Grove-Smith from the Passive House Institute in Germany echoed Enrico’s call for standardizing componentry and working to improve existing housing stock. To this end, the Institute have developed the EnerPHit standard for existing houses, Passive Haus Plus and Passive Haus Premium which include points for using renewables and low energy materials.

Jessica talked about having a strategy at the beginning of the building project deciding whether to do it all at once or carrying out the retrofit in phases. The Institute, while maintaining rigorous standards for the Passive House system recognises that in many areas where there is limited availability of certified componentry or small houses in shaded or cold locations, Passive House certification can be hard to achieve resulting in many “near misses”. They are currently working on how to mitigate this issue with the various Passive House branches around the world.

Barry McCarron’s talk moved away from the domestic to talk about CREST – the Centre for Renewable Energy and Sustainable Technologies in Northern Ireland. This building has met not only the Passive House standard but also the BREEAM Excellent and Net Carbon Zero certifications. As Barry says “The CREST pavilion building has the purpose of being a demonstration building for pioneering design principals and construction methods. It is an exemplar for other construction schemes”. Barry did make the point that it is important when building on this scale that a contractor who has had previous PH experience is hired and this was a challenge for the project.

What impressed me on the day I spent ingesting what I could about Passive House, is that this is not a system which is just for the domestic market. Schools, offices and public buildings could/should all be built to PH as a standard. Schools especially would benefit long term from having minimal energy costs especially over the winter period. The first thing that strikes you when you walk into a Passive House is just how good the air quality is. There are no marginal rooms, cold patches or stuffy areas. One can’t help but feel that this element alone could do wonders for student concentration in schools. That would be such an interesting study to undertake……

For those of you interested in experiencing just how good Passive Houses are, there are often open days held around the country. Check out www.phinz.org.nz for details.

The benefits of social housing to passive house standard

General

Overview

  • Passive House (PH) is a tried and true performance standard for building extremely low energy buildings.
  • The up-front costs are easily absorbed over the life time of the building because expensive plant is significantly reduced and does not require as much maintenance / replacement.
  • Many parts of Europe have a requirement for all their social housing & public buildings to be PH standard.
  • The PH system is most beneficial to those in our community who are struggling to pay for heating.
  • Through the PH Planning Package software building performance is guaranteed.
  • PH buildings are very comfortable and quiet with good air quality and high occupant satisfaction.

Benefits for social housing providers

  • Social housing providers would be showing leadership in building design.
  • A PH building would provide an excellent learning opportunity for other providers to learn about PH.
  • Tenants who currently cannot afford heating would be able to do so because heating bills would typically be less than one fifth or less compared with a typical Code built house.
  • For those tenants who are not heating their homes, the PH system would still provide a healthy home.
  • Because of the high surface temperatures achieved in PH homes it is not possible for black mould to grow.
  • Health issues arising from poor housing would be reduced meaning that there are benefits to other social health providers.

Thermal comfort and health

  • A PH building stays at a constant temperature throughout the year and there is little difference between summer and winter or day and night.
  • The internal thermal comfort can be controlled by occupants leading to fewer complaints.
  • The air quality is excellent.
  • There are very small variations of internal ambient temperature, so no cold / hot spots which annoy occupants.
  • PH houses are quiet without the constant noise of plant cycling through cooling or heating.
  • Once a PH has been ‘experienced’, it is very hard to accept anything less.

Energy / Operational costs

  • A Code standard house could consume over 100kWhr/m2/annum for heating but as a PH the building would consume less than 15KWhr/m2/annum.
  • There is significantly less heating plant to maintain and replace.

Construction

  • There are existing pre-fabricated wall systems that could be used that already have the windows installed together with an air-tightness layer for quick construction on site.
  • This project would also educate the construction community in the challenges and benefits of PH.
  • It is possible that local companies could supply some of the building elements such as windows.

Don’t settle for ‘code’

General

Why do we settle for so little when it comes to buying a house — the single biggest purchase most of us will ever make?

I’m an American engineer. I grew up with winters in the North-East, where the snow can be two metres deep. We know about cold; and we know how to insulate and keep warm.

It was a shock, on moving to New Zealand, to discover how cold and miserable so many houses are.

In New Zealand, the build quality is pretty good. The labour is skilled and the quality of the build is better than in the US. But the standard to which New Zealand housing is built is not very good.

If we look specifically at insulation, the r-values specified by the Building Code are easy targets to reach. They are very much a compromise, negotiated between the Government and the building industry. There’s a short term focus that looks for a very quick pay-off.

Buildings use a huge amount of energy: about 40 per cent of the total primary energy consumption in developed countries. The Passive House standard is one way to dramatically reduce energy use in this sector and thereby mitigate climate change. It’s relevant to renovations and retrofits as well as new builds.

Buildings use a huge amount of energy: about 40 per cent of the total primary energy consumption in developed countries.

As an immediate pay off, we’d also be living in healthier, comfortable homes and workplaces and paying much less to heat or cool them.

Homes built to the current Building Code have more insulation, better glazing and are better at keeping the heat in. True.

However, old, un-insulated, draughty houses were really good at one thing: drying themselves out. Air could flow through wall cavities to dry out any moisture that penetrated through poorly built or maintained window flashings, for instance. But now wall insulation is mandated and if moisture gets in, it can’t evaporate. Over 10 or 20 years, that could lead to serious rot.
Second, the Building Code specifies double glazing in almost all New Zealand climates. Double-glazing is great! But if the joinery is aluminium without thermal breaks, it will conduct heat incredibly effectively. That means heat loss and condensation: more moisture.

Old, un-insulated, draughty houses were really good at one thing: drying themselves out.

 

Thirdly, your average family is estimated to produce some seven litres of water a day through cooking, washing and breathing. Without some way to extract it, that moisture will build up in a modern, more air tight home, much more so than a ‘60s weatherboard.

In short, if you’re building a new home (or commercial building) understand the Building Code to be the bare minimum, not a target.

  1. Choose Your Builder
    Hire builders you trust to not take shortcuts. Details matter.
    Connector.
  2. Insulate!
    Insulate underfloors, ceilings and walls above the minimums specified in the Building Code, appropriate to your climate.
  3. Get Quality Windows
    Buy the best quality windows you can afford (at least double-glazed with argon fill and low-e coatings, with timber or properly thermally broken aluminium frames). If you can’t afford them, make your windows smaller.
  4. Properly Ventilate
    Ensure the house is adequately ventilated. At an absolute minimum, ensure fans in bathrooms and extractors above cooktops. Consider mechanical ventilation: small, efficient units that exchange fresh, filtered air for stale.

If ‘it meets Code’, it’s just good enough to be legally acceptable. Why settle for that?

A villa retrofit case study

General, Residential

Anne Rowe – January 25, 2016

We have the knowledge and materials to build outstanding new homes—but the fact is most New Zealanders are going to continue to live in our existing housing stock.

We can retrofit older homes in order to provide better health and energy efficiency, and really we should be doing so. These goals should rank higher when homeowners are planning additions or renovations.

Spending money on better insulation is not as immediately appealing as a flash marble bench top in the kitchen. The interior comfort that you experience in a well insulated, well ventilated house is not immediately apparent. However, spend a winter in a draughty, damp villa and these qualities are sorely missed.

Chris and I raised our family in a Wellington villa built in 1907. Like many people, I find these gracious old homes deeply appealing. The native timber joinery and stained glass windows are particularly beautiful. But living here has not been without its challenges.

A series of improvements have been undertaken since 2002. Here’s a run down of what we’ve done to make the house a warmer, drier and less costly place to live and work.

  • ’02: We renovated the house at the rear and insulated those walls and ceilings as part of the building works.
  • ’07: We installed gas central heating, distributed using very old cast iron radiators salvaged from a building site. These have the benefit of retaining their heat long after the heating has been switched off.
  • ’08: A double layer of insulation was fitted in the original part of the house: the first layer between the joists and a second layer rolled out over the joists.
  • ’09: A solar hot water 30 tube system was installed to heat a 270 litre water tank.
  • ’12: A land drain was dug at the rear to divert the water we had discovered ponding under the house! This was costly but had to be done and the reduction of the damp feeling in the rear of the house was immediately noticeable. The following winter’s heating bill was also much smaller than the previous.
  • While the house was being re-piled, we laid down black plastic to stop the damp rising. This is a cheap and efficient way to prevent cold and damp radiating from the bare earth under a house.
  • When we put in the new floor, a double layer of insulation was fitted underneath. In the areas that couldn’t be accessed from beneath the house, we fitted insulation panels between the floor joists from above, a tricky job.

We’ve also installed solar hot water and a grid-tied a 2kW PV panel system (we can produce a maximum of 15 kWhr on a good day).

The house is definitely cosier and warmer in winter than previously but it’s still not as comfortable as it could be. In 2016 we used our Passive House blower door tester to ascertain the air tightness of the house. The results showed that, under the standard Passive House testing regime, the air inside the house changed ten times in an hour, or once every six minutes. This is putting a significant heating demand on the house in winter.

In order to reduce this to an acceptable level of airtightness, which we believe to be in the order of three air changes per hour, we initiated a series of air tightness measures. The first one was to replace open recessed light fittings with closed LED type. As a temporary measure, draught proofing strips were applied to all of the openable windows. Extract fans were fitted with back draught dampers.

Our next project is to retrofit double-glazing and brush seals to our existing sash windows. This will be expensive. However, anecdotally, I have heard it makes a very big difference to the comfort levels in a room.

I hope this helpful. Your comments and questions are welcome.

Fact File

  • Built 1907 in Kelburn. 4/5 bedrooms. Weatherboard exterior, tin roof, timber piles. Some original sash windows replaced with casements in 1961.
  • Wall insulation: Greenstuf polyester 90mm thick R2.5
  • Floor insulation: NOVAfloor underfloor insulation R1.4
  • Ceiling insulation: Ecofleece R2.6 wall and ceiling 140mm loft (double insulated; ie 280mm)
  • Solar hot water: Apricus 30 tube evacuated tube system with 270 litre duplex stainless steel tank
  • PV: 2.0kW Canadian Solar CS6P panel with Enasolar inverter

Retrofitting? How to choose double-glazing.

General, Residential

With double-glazing now required in new homes, awareness is growing of its value and more older homes are being retrofitted with double-glazing. It’s not a cheap improvement and sadly, many people are making bad choices that won’t perform well.

There are many different types of double glazing. The better performing ones:

  • Are argon-filled. Argon is a gas that is less conductive than air. It is present between the two panes of glass.
  • Have a low-e coating. Short for ‘low-emissivity’, this is an extremely thin metal-oxide layer that reflects long-wave radiant heat from inside back into the house, keeping things cosier in winter.
  • Have spacers separating the panes of glass that do not conduct heat effectively. They may be made out of plastic or stainless steel — not aluminium.
  • Have good quality seals.

Compared to standard double-glazing, argon fill will reduce heat loss by 3-9 per cent, and low-e coating by 20-30 per cent.

But it’s not just about the glass—so don’t rely on R-values measured through the centre of the pane when you are comparing different windows. Ask for the ‘whole window’ R-value, that accounts for the performance of the glazing, the frame and their relative proportions. (Also be aware that if you read information from European sources, these will quote U-values. This is the inverse of the R-value, so the lower the U-value the better.)

Avoid solid aluminium frames

The frame is crucially important. If you are replacing the whole window sash, the worst option is an aluminium frame that is not thermally broken. Aluminium conducts heat very effectively: so while your expensive double-glazed glass is much better at keeping heat in, heat is going to pour through the frame that holds it.

It’s not just about wasting the money you’ve spent heating. Because of the difference in temperature between the outside and inside of the aluminium, a lot of condensation is likely to form on the inside of the window frame. Condensation means damper air and that can cause significant health problems.

Better frame options

There are good alternatives to solid aluminium, some more affordable than others. At the top-end, there are brilliant European made units designed to last 80 years that have outstanding performance (and look amazing).

Wooden frames are naturally thermally broken. Wooden/aluminium composites are also available. These typically have a solid timber core, timber inside and aluminium outside, with a range of colours to choose from.

Aluminium frames can of course be thermally broken — several ways of achieving this are detailed here, with drawings. These reduce issues with condensation but still conduct more heat than other frame materials.

And uPVC frames are almost certainly cheaper and will perform better thermally — like timber, it reduces heat loss through the frame by about 40 per cent. Some uPVC products have had bad press in the past; certainly it must be constructed with New Zealand conditions in mind given the strength of UV light here and our climatic variations. With modern specifications and manufacturing, you can expect a 30-year lifetime.

Period joinery

If you have period timber joinery, you likely want to keep the existing sash. Specialist joiners can remove the timber sash and fit a double-glazed unit into the timber. But old joinery typically doesn’t seal very tightly, so be aware that you’ll lose heat and have draughts through the cracks around the windows.

Other considerations

Because window frames are the weakest point in any building’s thermal envelope (the outside shell of the building), larger windows will perform better than the same specifications in a smaller window because there is more glass area relative to the frame.

Fixed windows will also perform better than ones that open. The ability to open windows on opposite sides of the house is important, because it creates cross-ventilation that can very effectively cool a house in summer. But consider having more fixed windows on the south (cold) side of the house.

Remember too that our climates vary considerably and in much of the South Island, triple glazing is called for.

More reading

See how heat is lost through aluminium glazing.
ECCA has developed an ENERGY STAR rating for windows to help compare different products.
Baffled by talk of mullions, transoms, sashes and casements? There’s an excellent glossary on BRANZ’s Renovate website to help you identify different window components.
Renall Windows in Carterton manufacture European style wooden windows.
Eco Windows import top of the line European made windows (but no longer manufacture in NZ).

Chris Rowe is a Director of CORA Associates and a certified Passive House Designer.

Passive house: A new way to create better NZ homes

General

what is a Passive House?

The Passive House building standard originated in Europe 25 years ago, and despite what uninformed critics might say, it’s an approach to building which is entirely able to be applied to construction projects in New Zealand. If you’re thinking about a new build or a significant renovation, it’s really worth your while investigating the Passive House approach.

The term ‘Passive House’ possibly belies what a game changer this standard is as it creates buildings that are a delight to live or work in while giving serious consideration to environmental concerns and energy consumption. These are buildings which have maximum internal comfort as explained in further detail below.

But firstly, don’t confuse Passive House with passive solar.

Cheap to run

Passive Houses are ultra-efficient buildings that need very little energy to heat or cool: the standard specifies no more than 15 kW per square metre of floor area per year.

For a 160m2 house, that’s just 2400kW a year, or about $58 a month based on typical energy prices.

They are also amazingly healthy, with outstanding air quality. You can’t be sure of that in a modern NZ house built to the current Building Code.

Flexible standard

The standard doesn’t dictate building materials; just about anything can be used, from luxury modern materials to straw bales.

There are now Passive Houses in New Zealand from Wanaka to Auckland. All of these are single family homes (starting at a modest 120 m2) but overseas, this approach is also being used extensively for apartment blocks, schools, supermarkets and office buildings.

Increasing numbers of buildings in Europe are now being retro-fitted to meet the standard as countries work hard to meet climate change commitments.

Comfortable

Any Passive House building will be well insulated, relative to the climate. An unbroken building envelope and high-quality windows keep heat in (or out, in summer). You can expect a constant temperature of 18-20 degrees everywhere, all the time — with little or no heating.

It’s also peacefully quiet inside a Passive House, and not damp: no more mopping up condensation on winter mornings.

Air quality

A small, efficient mechanical ventilation unit ensures the air is always fresh. A small heat exchanger will use the heat of the stale air being expelled to warm the outside air being brought in. It’s also filtered. This means no cold draughts, cleaner air, and no heat squandered on a cold winter’s night.

Culturally, mechanical ventilation is a new idea for us New Zealanders to wrap our heads around. But it’s a clever solution to the issue that many of our homes are empty for eight to 10 hours a day, and likely tightly closed up for security reasons.

Modern homes are also more air tight than the draughty 50s and 60s buildings we may have grown up in. This can cause moisture to build up in the walls and internally. A mechanical ventilation system will allow for the fact that windows aren’t always opened, especially in winter. The Building Code assumes that if windows can open, people ARE opening them for regular periods every day, throughout the day and night.

When did you last do that? (Last summer?)

Verified

Approximately 16 houses in New Zealand have been or are on their way to being certified. This means they have been tested with a portable blower door, which pressurises the house to 50pa to check for air leaks. This is first done when the building envelope is complete but still exposed. The second test is carried out by an independent certifier once the project is complete.

The additional cost of certification is insignificant compared with the total budget for a new build. This step verifies that the building performs to the expected standard. That way the client knows the design and calculations were correct and the builders did their job well; they got what they paid for.

Chris Rowe is a Director of CORA Associates and a certified Passive House Designer.

More reading

Watch New Zealanders talk about what it’s like to live in a Passive House – YouTube

Some of what you hear about Passive House is wrong

General

The Passive House (or in German, Passivhaus) concept is new here and not widely understood. It’s a building standard entirely relevant to New Zealand conditions. Here’s a general introduction. In this post, I want to clear up some of the misconceptions I hear about Passive House.

We don’t need that here — it’s designed for the much colder winters in northern Europe.

This objection comes from people who just don’t understand what Passive House is. Because it’s a building standard, measured by the (very small) amount of energy needed to heat and cool the building, it is extremely flexible. Yes, the examples we see from Germany are super-insulated—because they are built for their very cold winters. In almost every part of New Zealand, the same levels of insulation are not required.

I used NIWA data to develop energy models for 17 climate zones the length of New Zealand. This gives us reliable, location-specific data. Passive House designers can use this to help clients make good, cost-effective choices about building components and design.

(This compares to the three climate zones specified in the Building Code—suggesting a beachfront home in Nelson and one up a mountain in Queenstown require the same amount of insulation. You don’t need to be a building scientist to know that’s not true.)

Airtight buildings? That’s unhealthy!

Agreed. People need fresh air and homes need to be regularly ventilated. Older style homes were ‘leaky’ enough that air moved through the sub-floor, roof space and around windows and doors. There was way too much air exchange on a windy day and not enough on a still day. It’s a random and uncontrolled process that doesn’t produce good outcomes.

Modern conventional homes are much more air tight than ones built in the 1920s or ‘60s. These are the homes to worry about! The Building Code still presumes that as long as windows are designed to open, occupants are opening them: regularly, every hour, day and night. Realistic? No.

Increasingly, homes are shuttered tight for long hours as no one is home during the day and people are security conscious and don’t want to leave windows open. A certified Passive House building envelope eliminates draughts and keeps the temperature even. It also keeps out insects and airborne pollutants and irritants and reduces noise.

A fresh air system automatically exchanges stale inside air with filtered air from outside, which also regulates humidity. (A certified Passive Houses is never damp or mouldy.) When it’s cold, the warm air being expelled first heats the fresh incoming air, preventing draughts and wasted energy.

The fresh air system is made up of a mechanical ventilation unit integrated with specific extraction in bathrooms and kitchens. They are small, quiet and very cheap to run. If there’s an extended power cut, just open a window!

It’s really expensive

If you take existing plans and say to a Passive House designer, make this a Passive House, it’ll likely cost 10-12 per cent more. But don’t make it an add-on: design a Passive House from the outset. It’s not just about fancy windows or air-tight building layers.

Orientation, footprint, position of windows and how the house relates to its environment are all things to be considered. Go to a designer and tell them your budget. You can get a Passive House for what you have to spend by sensible, reasonable compromises — reducing the floor size a little, simplifying the building shape, even reducing the window area if necessary.

eHaus, which has built more Passive Houses in NZ than any other company, say the housing pressure in Auckland is spurring enquiries from people looking to build small (80m2) dwellings on sub-divided land or backyards. Yes, you can build a modest Passive House without spending a fortune.

It’s not that different from passive solar

Wrong. Building professionals who should know better have made confusing statements about passive solar or “passive design” and Passive Houses. Passive solar is about orientating the house and positioning windows to capture the heat from the sun. Glazing lets the heat in and thermal mass like concrete floors stores it.

Thermal mass only works if you like temperature variation. If it’s hotter than is comfortable, some heat will get transferred into your brick internal wall or bare concrete slab. Later when the temperature drops, heat will be released.

I live in a passive solar house with a wall of north-facing glass and it’s not pleasant. The average temperature disguises the massive daily fluctuations. On a sunny day, it can be above 30 degrees inside or more and at night it drops down to within a couple of degrees of the outside temperature.

The beauty of a Passive House is that it will stay 20 degrees everywhere, all the time — with virtually no heating source. When the temperature is constant, any thermal mass will equalise with the ambient temperature indoors and it has little or no effect.

Keep in mind that Passive House is an open source standard — it was deliberately created that way. So anyone can call their building a passive house. Only if it’s a certified Passive House, can you be sure it is what it says it is.

Jason Quinn is a mechanical and aeronautical engineer and ex-NASA rocket scientist now working as a building scientist. He is a Passive House Designer and Certifier. He consults for CORA.

More reading
The Passive House Institute of New Zealand (PHINZ) has a useful site with many resources and a great FAQ page.
Here is a list of certified Passive House designers and consultants in New Zealand.
The Passivhaus Handbook: A practical guide to constructing and retrofitting buildings for ultra-low energy performance by Janet Cotterell and Adam Dadeby is a comprehensive resource.

Let’s raise our expectations

General

40,000 children a year are hospitalised with poverty- and housing-related illnesses. Children are dying due to poor-quality housing in New Zealand, according to the former Children’s Commissioner Russell Wills.I’m very glad that in recent years there’s been a lot more attention given to the link between cold, damp housing and health.

I grew up in the 60s in Wellington and while my childhood experiences horrify people now, it was just considered normal back then. Everybody’s house was cold in winter. Everyone gathered in the one room that was heated in the evening and then slept in bitterly cold bedrooms under heavy layers of blankets (with several hot water bottles!).

My brother and I had south-facing bedrooms in a single-skin brick house in Mornington that caught the full brunt of the Wellington southerly winds. The walls of my room were wet and the windows streamed with condensation. I recall writing my name in the black mould on the walls and window sills. When it was too wet outside to dry the washing, Mum would hang it in a cupboard in my brother’s bedroom.

We were considered ‘sickly children’ and missed a lot of school. I recall three bouts of pneumonia and being sick with bronchitis much more often, including in summer. I had glue ear, which led to a burst eardrum. My brother was a severe asthmatic and had to be hospitalised sometimes, once spending days in an oxygen tent.

While my parents were professionals, money was tight. We were in no sense neglected. We ate like kings—Mum grew veggies and prepared amazing meals—and were well clothed. (And Mornington then was a wonderful place for childhood exploring: we were free to roam in the gorse and blackberry, building forts and making our own games.)

My father was a child during the Depression and he grew up sleeping in a dirt-floor dugout underneath the family home in Brooklyn. Mum was the oldest of 10 children. Both wanted the best for us and did what they could with what they had—and what they knew. Mould would be periodically wiped off and I remember Dad painting fungicide (!) on the brick exterior.

Nobody, including the doctors, made a connection between our childhood illnesses and our living conditions. But now the cost of cold, damp housing is firmly established, thanks to the work of researchers like Philippa Howden-Chapman.

We’ve come a long way, but not far enough. We understand that cold, damp homes are not OK and the consequences are serious and far-reaching. But too many families are living in sub-standard housing, where cold, damp and illness are still the norm.

More reading

A good summary of the research is available at Environmental Health Indicators New Zealand’s website. Also at the Science Media Centre