Windows and Doors....a passive house nightmare!

New Zealand is not yet quite ready for a Passive House revolution. According to PHINZ there is only one approved supplier of Passive windows, and that in Otago ! Our designer obviously had some thoughts on this matter, but, as so few houses have yet been built experience is limited. As you can see the construction is quite complex to achieve the thermal breaks and strength.

Our first job therefore was to Google Search PVC windows and doors/Passive windows and doors.

Once one eliminates very expensive solutions or all wooden ones you are currently left with 4-5 NZ provider, we checked out the following: (see weblinks)

NK Windows in Christchurch- NK Windows
Advanced uPVC Windows in Bulls-Advanced uPVC
APL in Christchurch (Klima range)-Klima from HPW
Warm Windows in Auckland-Warm Windows

Each of these suppliers manufactures under a licence from a German/Austrian manufacturer with PVC and profiles being imported from overseas and then assembled in NZ. Watch out for future providers supplying PVC from China as not all grades of PVC are suitable for NZ's high UV content.

We have kept a detailed spreadsheet of all our inquiries of these providers and it has been our experience so far that none of them can provide the entire range of what you may want in a Passive House - unless you want all white PVC doors and windows! (Boring), Some providers have quite different profiles of frames which can make the steps into homes difficult and some cannot yet produce very large windows to conform to higher wind speed zones.

During our investigations, which have involved factory visits to 3 of the vendors to check out what they really can do, we have found out that

• If you are older people, or going to be one day (without getting a hernia) big sliding windows need a "Lift and Slide" mechanism (web)- not everyone can do this yet- watch this video  Monumental Lift and Slide
• Some vendors ship all their doors fully glazed and others just as frames with glass being installed at site- there are risks associated with this!
• Some vendors do not yet have all the U and R values for the various sizes of frames, making PHPP calculations more difficult.
• Some manufacturers only sell via agents many of whom have yet to fully grasp what a Passive House is all about !
• Not all manufacturers adequately describe their products on their websites- we thought only tilt and slide windows were made by many but often these are not suitable, especially when using roller blinds and curtains, but PVC awning windows and casement ones all have modern security and design improvements to make them suitable for a passive house

Doors- especially good looking front doors is another story which I'll keep for the next epistle!

The design contract...where ideas become detailed plans

In a number of roles I have had in my consulting years I have found that keeping all elements of a project separated by contractual boundaries does not lead to the best outcome. Thus, right at the onset of the project we made it known that we wanted to be an integral player in the design phase and that we wanted the builder too in that mix. Fortunately eHaus and QBuild already had a workflow that had several interactive stages so that was readily accepted.

Our kick -off meeting with Jon Iliffe, principal of eHaus, went well and we negotiated a timeline that was quite "sharp" in its delivery of key milestones. They inferred that to achieve the timeline would be somewhat challenging for all concerned, especially us, as it required a lot of key decisions in short time frames. At that stage I don't think they knew who they were dealing with ! They were also keen for us to engage an architect rather than an architectural designer, but we had already considered that quite carefully and knew that we did not want to have something that incorporated "flashy ideas" at greater cost.

A key lesson for anyone designing a new home from scratch is to have quite a strong concept of what they want delivered, especially how it fits with one's values and long term desires. In our case we wanted a home that was easy to care for, was built with long lasting materials, that fitted into the local environment and was suitable for us to live in, hopefully, for many years to come. Having had a 3 storey property to look after for 17 years there were definite things like surface accessibility to clean that were in the forefront of our thinking.

We wrote our values, needs and key constraints down and had them available for the first site meeting of all 3 parties. This took place on a beautiful Autumn morning and everyone was very enthusiastic about the site's potential. This visit raised a few matters regarding where key elements might be located, eg the buried water tanks one has to have at Kapiti, so that was added to our growing list of queries.  We found in this stage that one needed to keep an Issues Log so that one could track what was being addressed and by whom.

After this kick off meeting we started to deliberately go out 2 or 3 times a week to look at specific items of the design that would help us make decisions. Some of these were easy to progress, some were very difficult.  For most aspects of a building we found that once you have a plan to send a vendor/supplier they will be prepared to give you a free quote. We'll cover our experiences of this in subsequent blogs.  Its a good idea to set up box files on each topic and an Excel workbook with all the various areas in as there is a huge amount of information to progress and track.

So ...slowly the design progresses and you eagerly await the first concept plan...

Establishing the passive concept in our home

By now you have probably got hold of the "passive house" concept in theory...now it was time to look at it in practice and think how it gets incorporated in a future home. To do that there are a couple of key elements....a) visit some passive homes and b) start discussions with a passive house designer.

Our first visit to a passive house was the eHaus showhome at Waikanae designed by eHaus and built by QBuild Ltd. One of the first ideas we had to comprehend was of the style and nature of the windows and doors in such a house and of the concept of the "passive core" of a house and the non-passive elements. At Waikanae the garage is used as QBuild's offices and it is non-passive, one then enters a tight seal door into the rest of the "passive core" house. This element is quite critical in the design as it means that anything non core really has to be at one end or in one corner, or it will become unworkable. So in our concept the garage is also non core and is at the Southern end.

Having established this design factor the next element is maximising the layout with respect to the movement of the sun. EHaus advised us at the onset that depending on the design specification adopted we may have too much heat coming in with this layout and may have to have external shading to lessen its effect, so we judiciously limited the number of large windows facing our main view of Kapiti Island, but this changed over the evolution of the design. Lesson 1- go for what you want to happen, not what you might fear will have to change!

As part of our first meeting with Ehaus' principal, Jon Iliffe, he took us to his own passive home just outside Whanganui. Some of the features we saw there have been incorporated in our own home- light sensors in key areas, effective water heating systems, solar generation etc, so it is always worth looking at the learning lessons from others. Jon's home has been awarded a Passive House Institute's prize.




Next time we will cover what you need to tell your passive house designer before he/she starts work!