Basic Features ...
A Passive House is a building in which indoor air temperatures above the WHO recommend minimum of 18°C are maintained year round without the need for heating appliances. For indoor comfort however, 18°C are not sufficient; for a comfortable home, a minimum of 20°C is required. In a Passive House, the small amount of energy needed to lift the temperature profile accordingly can be supplied via the ventilation system.

That’s right, you don't need neither radiators nor wood or gas burners nor air conditioners to live in a comfortable, dry and well ventilated house. This isn't a case of wishful thinking but rather of applied physics.
All you need is a maximum heat load of 10W/m². Read here how to reduce the heat load ...

Each new building can be a Passive House. Personally I have been involved in the planning process of a Passive House office building, and a Passive House school. They all have great thermal comfort in common. Read more ...


Is this an experimental concept?

No. There are currently more than 20,000 Passive House buildings operating in Europe (most of them functioning under considerably more extreme temperatures, than you will find in New Zealand), the oldest one of them up and running since 1991. The Passive House concept is proven both scientifically and empirically to work well.


Is a Passive House also a Zero Energy House?

No, it is not. You still need a minimal amount of external energy to provide a comfortable and healthy indoor climate in a Passive House, although in some regions in NZ that amount would be next to zero. You certainly can go the extra mile, and turn a Passive House into a Zero Energy House. But this very last part of the way is the most expensive. A Passive House tries to balance economy and ecology, and therefore stops short of the last meters. You can easily cover the remaining need for heating and cooling energy with renewables, though, but the therefore applied technology is mostly active. Read more ...


Why is it called Passive House?

A Passive House tries to provide a comfortable and healthy indoor climate without the need to use active heating or cooling appliances. It heats and cools itself. There are machines to facilitate this purpose, namely an efficient ventilation system (no air-conditioner!), but I consider a ventilation system a vital ingredient of a healthy and comfortable home anyway, so it’s not specific. Other than this, there’s no machinery needed. A good ventilation system by the way is easier to operate than your average remote control.


Do I need to have a north facing site to build a Passive House?

No, there are plenty of examples where a Passive House works perfectly without being aligned ideally. It’s a bit harder though, but definitely possible.


Do I need thermal mass?

No. Thermal mass is a supporting actor. Nice to have, but not unalterable. Read more …


Can I open the windows in a Passive House?

Sure you can! Only – you don’t need to do it any more. But you definitely can do it, if you want. That’s freedom of choice, isn’t it?


Are there specific shapes needed for a Passive House?

No. You might very well build a Passive House that looks like a 19^th century villa. You can have it look Tuscan style or state house, or just plain modern. They come in all sizes, too.


What about summer?

The good news: insulation works both ways on opaque components like walls and roof. The “solar” design you chose to catch the sun in winter however could be a mayor problem in summer. One more reason why you shouldn’t aggrandize window sizes, because thereby you also magnify summerly trouble. But there is a solution: keep the sun out in summer simply by using movable shades, like shutters. Always put them on the outside of your windows. It would be nice to automate closing and opening in dependence of solar radiation, too. That could be done quite easily with a small photovoltaic sensor and solar driven motor. Otherwise you might need the exercise of doing it yourself…
The ventilation system can, in combination with a mostly passive ground heat exchanger, work as a dehumidifier and also cool down indoor air a bit. Again: a big step towards comfort with only a small amount of energy!


How does it work?

It works by minimizing heat losses and maximizing passive heat gains.
To minimize heat losses you first and foremost need lots of insulation (roughly 15 cm+, depending on location in NZ) . By insulation I mean materials with a thermal conductivity ≤ 0,1 W/(m K). This could be wool-, cotton- or polyester fleece, cellulose, glasswool, polystyrene, foam glass, fibreboards, straw bales or others – in a word: low density materials with many enclosed air cavities.
Neither rammed earth, nor clay, nor loam, nor concrete would do, since all of those don’t have noteworthy insulation values. Read more ...
All the windows, too, need to be very well insulated. And don’t exaggerate window size.

Think of your home as a present: you need to wrap it all around neatly. And don’t forget the corners! Read more ...

Next you need an airtight barrier interior of the insulation layer. That could be made of any material that is and stays airtight. Building papers, polyethylene foil, OSB panels, plaster etc.. Just don’t forget joints and connections. They need to be airtight, too. Read more …

You need to ventilate your home. But you don’t need to loose indoor warmth doing it. Heat recovery is the solution. It only works well in airtight houses, though. Read more …

Now that you’ve cut the losses, maximize the gains.
Catch as much winter sun as possible – but avoid overheating synchronously.
Try to align the house as north facing as you can, and provide moveable shades on the outside of the building.

You also receive gains from appliances and occupants. But it isn’t very wise to maximize gains here. In the case of appliances: you wouldn’t want to waste the energy you save on heating to run inefficient appliances (efficient appliances only generate minimum heat). And I don’t think you’d want to subdue your families planning to heating purposes either.

Heating problems solved, think about warm water supply. You can easily get it without burning fossil fuel or fossil generated electricity. Solar water panels are readily available to do the job without sending monthly bills. There are systems operating in Europe, where solar panels are integrated into the heat recovery system. Even a clothes dryer can be part of the ensemble. It’ll then all work mutually beneficial. So far you don’t get these systems here. Hopefully it’ll only be a matter of time. But even without the most sophisticated techno: it is very well possible to build a Passive House in New Zealand!


Are you professionally involved in planning or constructing Passive Houses in NZ?

Do you live in a Passive House under the above definition somewhere in NZ?<

Do you provide components that are suitable for Passive Houses in NZ?<

Are you involved in research on Passive Houses in NZ?

I’d like to get to know you!