When we are talking about sustainable homes a lot of times it is about reducing energy and carbon emissions. While I like to know more about the carbon footprint of building a home (the “embodied energy”) and the footprint of operational use later on, I think it is also good to look at those numbers relative to other emissions we cause as a household.
Motu Economic and Public Policy Research researched the average carbon footprint of a New Zealand household 
The average household in New Zealand causes 15.6 t-CO2eq per year. The decomposition shows that housing and utilities cause 25% of the total footprint, transport which also includes flying is equally big with 25%. With the EV we bought and future building of our sustainable house we are doing pretty good in these categories.
Quite astonishing is however the impact of the food category with a massive 40% share which is not included in most available household footprint calculators. Most of the footprint of food is related to eating livestock (beef and lamb). Only 20 per cent of emissions from food are energy emissions, emissions from the burning of fossil fuels. The other 80 per cent of emissions are methane from livestock and nitrous oxide mostly from animal urine. I already knew about the impact of eating red meat but looking at these graphs is just another reminder to keep our consumption of red meat as low as possible ( I have trouble convincing myself to become a vegetarian at this point but who knows there will be a point in time when I feel confident enough to completely cut out meat). Below a picture I found from the USA with statistics of different foodprints of food.
We have already planned to create a vegetable garden at our home and this will contribute as well to keep our emissions of food as low as possible but we should take it a bit more serious.
To calculate your own household footprint in New Zealand Enviro-mark has a calculator on their website although it doesn’t take food into account. 
Putting our numbers in for our current house and lifestyle in ton CO2e
- Home energy: 1.2 ton ( all electric including energy to charge our car at home or at chargers)
- Private transport: 0 (5.7 ton if we still had the petrol car)
- Public transport: almost zero
- Waste: 0
- Flying: 0 in 2016 (one year without flying!), we just had a domestic flight with the family to Nelson for 2.8 ton and would like to visit the pacific Islands this year which will cause 4.1 ton in CO2e emissions if we go.
So most of the emissions for our household are caused by flying and still eating red meat.
Another conclusions you can draw from these figures that looking at the New Zealand situation building an energy efficient home is not contributing a lot to reduce the footprint of New Zealand since most electricity is already generated by renewable energy. Equally important to us is however to create a home that is comfortable, healthy and which has low operational costs which can all be achieved by the passive solar design principles.
Not looking at buildings but at the challenges for New Zealand to reduce emissions the main categories to look at are agriculture (49%) and transport which is the biggest category within the energy emissions.
 household. http://motu-www.motu.org.nz/wpapers/16_20.pdf