Extolling the benefits of PassivHaus
eHaus builder, and eHaus Rodney Licensee, Bruyere Ltd, run by Terry Bryers, uses the latest world leading high performance technology to build healthy, comfortable homes that provide up to a 80% reduction in heating and energy costs.
Terry who is a Certified PassivHaus tradesperson, Master Builder, LBP and Carpentry Site 2 qualified, began his carpentry apprenticeship in 1970 and was trained to build homes aligned to the New Zealand standard code.
It wasn’t until 2013, dissatisfied with the low performance of these homes, that he went looking for an alternative construction option.
“When I stumbled across eHaus four or five years ago, I realised this is where New Zealand’s building industry needs to be,” he says.
“I was building my own home and I wanted to start down the energy-efficient road. I found New Zealand owned and operated company eHaus that uses PassivHaus design and build principles from Germany, which encompass unprecedented health, comfort, and energy efficiency benefits, as well as architecturally designed quality homes.”
eHaus builders now cover the country with 11 licensees from Southland up to Terry’s license in Rodney. Terry says there are five principles of PassivHaus design and build.
First, a continual layer of insulation right around the building, including external walls, floor, and ceiling.
Second comes no thermal bridging, or no heat dissipation through products like aluminium joinery where warm air is sucked through the aluminium and condensates on the window pane. Thirdly, airtightness.
Certified PassivHaus airtightness requirements are 0.6 air changes per hour at a pressure of 50 Pascals, and a standard New Zealand building code home will leak at a rate between four to eight air changes per hour, while an old villa will come in at 25 to 30 air changes per hour.
“When the building gets to the point before linings go on, a blower door test is performed.
The doors and windows are closed and a blower is attached to a computer to test the airtightness of the home.
“Any leaks can be remedied at this stage of the build to ensure complete airtightness.”
Terry currently holds the eHaus record for airtightness for a home he built in 2015, which achieved an airtightness result of 0.28 air changes per hour at a pressure of 50 Pascals. Principle four is the use of specifically designed joinery.
Lastly, as the house is airtight it is essential that it is e ventilated. eHaus uses a mechanical heat recovery ventilation system to bring filtered air into the building.
“That means no mosquitos or pollen is coming into your home,” Terry says.
“Filtered fresh air goes into your bedrooms and living areas then returns through the system in your bathroom where it’s taking out all the steam and from your kitchen where it’s taking out any odours.”
Terry says the system removes 90% of pollutions resulting in healthy clean air, “which is fantastic for those who may suffer from any respiratory conditions such as asthma”.
“As the air is transferred out of the recovery system all heat is transferred to the fresh air coming in, keeping the home at an even temperature and reducing energy costs.”
Terry is working on his new home which is being built using the PassivHaus prinicples , while he lives in his converted garage, which was also built using some of the PassivHaus principles.
“What we don’t get is when we’re lying in bed in the morning and the sun is shining through the room, you don’t see all the little bits of dust in the air. It’s just not there.
“There is quite a lot of air going out of the bathroom, and you can hang your towel up after your shower and it’s dry as a bone the next day.
“There is no heated towel rail. In our new home we’re having a drying cupboard in the laundry, connected to the ventilation system.”
One of eHaus Rodney’s recent builds is on the market at the moment after being built for about $2 million, and is now priced at $6 million.
“People are starting to realise the difference of building a house that’s comfortable to live in and low cost to run,” Terry says.
“The houses are all architecturally designed and constructed to the specific regions weather climate New Zealanders are wanting more from their new builds and an eHaus is providing that solution, these houses are guaranteed to perform before a single stake is put in the ground.