Call us

+64 27 323 2025


Passive Houses

Energy efficient housing

What is a passive house?

Jonny is a certified passive house tradesperson. A passive house is a performance standard that is well above the NZ building code which consumes up to 90% less energy for heating and cooling.

It has:

  • consistent temperature throughout the home (average 20 C, winter or summer),
  • continuous filtration of fresh air through a home ventilation system with heat recovery.
  • no mold or condensation anywhere.


Photo examples of passive houses and not the work of JW Building.
Image credits  Markus Merz and  Team Green Architects

Passive houses have a home ventilation system with heat recovery. This takes the old air from the wet parts of the house; the kitchen and bathrooms and exhausts it through a heat exchanger which is also bringing fresh outside air through that same heat exchanger. It works the same way in reverse as air-conditioning.  So minimal energy is wasted by opening up windows to ventilate a home, although you can definitely still open your windows if you wish, but is not necessary.

Here are some tips for improving the performance of your home;

  • Minimise draughts. Even a gentle wind can suck the heat out of a building through gaps in the building fabric and through penetrations for pipes and wiring.
  • Use at least thermally broken windows, European timber triple glazed windows is best.
    If in southland have 140mm thick walls and Insulate well above NZ Building Code with minimal weaknesses. i.e a design where the insulation can be consistent even to the edges and corners of the house.
  • Minimise thermal bridges.


It all starts with a conversation. We enjoy getting to know you, understanding your project brief so we can deliver the goods. We will communicate with you from start to finish - that's out promise.



We work with you to meet your expectations. We can present ideas on materials, design and styles that will meet your objectives, and point out pros and cons to help you make informed decisions.


This is where your dreams start to take shape! Watch as we build within your time frame, your budget and deliver the home of your dreams