Are you 2030 Ready for Building for Climate Change?
Climate change is a contentious concept, capable of sparking massive debate. However, change is something we as humans are wired to be uncomfortable with. There is a saying “There are three guarantees in this world, change, death, and taxes”. And while taxes can be dodged (to a degree) change is the one guarantee we have the ability to use as an opportunity for progress.
And building for climate change is here. It's no longer just a point of conversation, it’s a reality currently in the first phases of being rolled out in building legislation and processes.
What does this mean for the average New Zealander who has or wants to buy or build a home?
One of the aspirations for building for climate change is the energy use of a home. This graph shows how a code-compliant house today compares to the changes that are proposed to be in place by 2030 for new buildings. Just to highlight, that most code compliant homes are built to the minimum standards, which fundamentally are the worst performing buildings you can legally build at the time.
The building for climate change targets for energy consumption in buildings is set to decrease from our current building code level of approx. 120kWh/m2a to 15kWh/m2a by 2030. Simply put, this figure is the power consumption of each square meter of floor area needed per year to keep a constant internal environment at a healthy 20 degrees Celsius.
We have seen the minimum thermal criteria threshold rise in the Building Code recently with changes now in place for increased performance in our windows and doors. Moving forward, in the near future, homes will need to be thermally modelled at Consent stage as proof of compliance, and the energy targets are moving towards the Passive House Standard.
Download a copy at https://www.building.govt.nz/assets/Uploads/getting-started/building-for-climate-change/work-programme-building-for-climate-change.pdf
What does that mean? It means that for every square meter of floor area of your home, the energy to heat, cool and operate that home needs to be reduced by nature of the design. It also means that healthy temperature ranges are going to be considered in the design and not left to chance or up to the behaviour (and additional cost) of the user.
Today a 200m2 home, built to our current building code, heated, and cooled to remain at 20 degrees Celsius year-round would use approx. 24,000 kWh of power a year (200m2a x 120kWh/m2a). At 32c a Kilowatt hour (as an approx. New Zealand average in 2023) that equates to $7,680 to power a 2023 code-compliant house to stay at 20 degrees Celsius year-round. (I realise people don’t have power bills this high, because they don’t keep their homes at 20 degrees Celsius year-round, but it puts things into a comparison) That’s $640 a month currently.
A Passive House which is designed and built to the max energy use of 15 kWh/m2a with a floor area of 200 square meters would use 3,000 kWh of power a year (200 m2 x 15 kWh/m2a). At 32c a kilowatt hour (as an approx. New Zealand average in 2023) that equates to $ 960 to power a 2030 Code Compliant Passive House to stay within 20 degrees Celsius year-round. That’s $80 a month currently.
Passive House Design and Construction is roughly estimated at being 5 – 10 % higher than the worst preforming building legally able to be built today (This is a current code compliant home). With rising electrical prices said to double if not quadruple in the coming 5 years, how much more is your home going to cost you to heat and cool (and be comfortable and healthy to live in) versus how much more to build better today?
That house that is code compliant today (ignoring existing housing stocks) will be behind code in 2024 whilst that Passive House built today will still hold its value and still be cheaper to operate in 2030.
By 2030, that Passive House will still be compliant, and all new builds will be to this standard. Passive House is an international model tool and certification system that is over 30 years old. It hasn’t changed much in that 30 years so it safe to say it’s a stable benchmark to aim for.
Given the wise words I heard from my uncle when selling my first house “your house is only worth as much as someone is prepared to pay for it.” How valuable is your home going to be in 2030 and how expensive is it going to be to operate and live in it?
Why wait to do better, when we have the tools to make it happen today and you can start to gain the rewards right away? A healthy comfortable home that is economical to heat and that will hold its value. If homes are our most valuable asset, we need to plan for them to be.