IDEAL House – New Zealand

Project Goals: Certified Passive House, Positive Energy & 8/10 Homestar design. Proudly supported by IDEAL Electrical Suppliers.

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Blow-in glasswool & Summary Sheets

I was just talking to a designer working on a new Passive House for a customer in Taupo, and we had a great discussion around all things high performance. Interesting that he was looking to use 140mm external framing (no nogs or dwangs), rigid air barrier on the outside, and 45mm cross battens for the internal cavity. This is my favourite construction. In this situation, the only product I would use for the external framing would be Jet Stream MAX from Knauf Insulation. It goes in dry, and can’t settle in the walls over the lifetime of the building, and can provide a higher R-value (R4.3) than any standard batts in the market, and perfect when you have deep cavities with long vertical runs. It’s also Codemark certified, so a breeze through local Council. We also discussed the benefits of using this in the midfloors and his skillion roof also. If I was to build again, this is the only insulation product I’d use without question:

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I also emailed the designer copies of the signage which we had displayed in the house, and thought these would make great summary sheets for everything on this website, without having to trawl through the posts. So here they are! (Click to download).

A4 Summary Sheets







A3 Summary Sheets







Remember, the Building Code is a minimum, not a target!

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June update

It’s been a very warm June, but temperatures are now starting to fall. We’re really pleased with how the home is performing this winter after some tweaking to the ventilation system earlier in the year. We’ve had two fires so far this year, but we cooked the home and had to open the windows, otherwise we haven’t run any heating. Great to see temperatures holding up above 20 and humidity well down on outside. Temperatures bouncing over 20 remind me of a stone skipping across water. I’ve been trying to get the kids to wear PJ’s to bed (given it’s June), but they just strip them off and complain they’ll get too hot. What an environment to grow up in! (And my coffee tree is doing really well as well).

Ideal House temps June 2016

Ideal House, Humidity June 2016

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Open Home Sunday 8th May

What better way to spend Mother’s Day than to visit a Positive Energy house! It’s an unusually warm autumn (sensors showed a ‘low’ last night outside of around 19 degrees) so you won’t get the full experience of inside/outside differential, but there’s still plenty to look at and learn.

For those that cannot make Friday the 6th at 10am, the home will also be open Sunday the 8th May at 2pm. Please RSVP to if you plan to attend.

Sensors April 2016

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Ecotricity & Open Home 6th May

We have had ongoing issues with our metering and grid connection since we moved in due to an error when we were first put on the national register, however we were recently recommended Ecotricity. They have since made all our problems go away. We just finished our first month with them and I am impressed. Although we have a small contribution to make (essentially paying for the privilege to use the grid as a battery) I think $38.83 for a month’s power for the home is not too bad for 3 adults and two kids. Interesting in April we imported 273kWh, and exported 768kWh. A good production month.

Our next open home is this Friday the 6th of May at 10am. Please RSVP to if you plan to attend.

Ecotricity April Bill


Filming, April Temperatures & Power

It’s nice to feel some bite in the air in the morning now (when we step outside), and also to see the outside temperature monitor start dipping lower and lower each night. Autumn is definitely beginning and winter is not far away. The reading dropped to 13.59 degrees C this morning before sunrise, while we were enjoying comfortable 21-23 inside. Now is the time of year that we start to appreciate building higher than Code, and we’ll start to close up the windows and revert back to rely primarily on our balanced heat-exchanged ventilation system.

We have filming again on Friday for the Living Green TV Show, due to air later this year, so we’re adding some final touches to the home. When that is complete we will announce some more open home dates.

April 2016 2

We’ve also plotted all the energy consumption and production (import and export), and are showing a nice gap proving we are definitely positive energy. The below graph has the import in blue, and export in red.

The first six months we were charging an electric vehicle, however it does not seem to have made a significant difference. Interesting is that our consumption is very flat through the year, as we haven’t used any dedicated heating (an occasional wood fire, more for ambience), so the extra power will be more lighting during the shorter days and more use of the dryer. I’m keen to do some digging around and see the variation between summer and winter for homes in our area which rely on heat-pumps to heat their homes.

We have also just changed over to Ecotricity, and their service has been amazing. They come highly recommended.

Ideal House readings

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NZGBA Open Home Event 2nd March

Our next open home will be hosted by the New Zealand German Business Association on Wednesday the 2nd of March, 3:50-6:30pm. You can either join the tour group in Auckland City and catch the ferry, or meet at the home. More details below, otherwise please email There will be a small cost which goes towards transport and refreshments.

We look forward to seeing you then!