Energy efficiency is essential. But can we afford it?

H1 Provides for the efficient use of energy and sets physical conditions for energy performance.

When New Zealand signed the Paris agreement and committed itself to a target of 50% of total energy consumption to come from renewable sources by 2035, and net zero greenhouse gas emissions by 2050, did it also commit itself to dramatically improving the energy efficiency of our homes?

According to MBIE’s quarterly data and analysis on electricity generation and consumption, 40% of our total energy demand comes from the residential sector. While our hydro and geothermal production has remained relatively constant (<2% change between 2020 and 2021), our consumption of coal has increased by 40%, and oil by 97%. We don’t seem to be on track.

So if we can’t or won’t convert our energy source, then we must change our energy use to meet our targets. MBIE recognises this and offers grants to insulate in ceilings and underfloor. Socks and beanies for New Zealand Homes. But is it enough? It seems not. “Warmer Kiwi Homes” grants were offered in 2019 but our total energy demand (residential) has increased by 2.1%.  Consuming a whopping 13,260 GWh in 2021, enough energy to boil 60,272 Olympic-sized swimming pools. This increase in use mirrors the increase in population during the same period, but correlation is not causation. How can we expect reduction in reliance on fossil fuels if we don’t increase hydro or geothermal production, while maintaining a steady increase in population, and we don’t do anything else?

It seems energy efficiency is essential, but can we afford it? This might sound like a trick question but it’s not. Most people agree we need to be more efficient, but the evidence shows we are not putting our money where our mouths are. Only a handful of homes each year are recognised as high performance, but does it have to be this way? Robert Whitehouse of Energy Efficient Homes Ltd and Whitehouse Builders thinks not.

Robert can build you a high-performance home for around $3000 /m². How does he do it? Design. Design of the build and design of the process. He has whittled his processes down to a fine art and he lays it all on the table for the customer. He explains to the client how much the “extra” bits cost and steadily they find the sweet spot.

“Energy efficiency is affordable.” says Robert, “That’s what we do.”

By understanding the needs of the customer and combining this with his experience, he can find a design that fulfils its brief but still doesn’t cost the earth.

The changes to H1 don’t seem complicated at first. Small changes here and there. The biggest change is in the roof space from R 2.9 / R3.3 to R6.6 from 1 May 2023. But this now means the designers must pack more insulation into their designs. Roofs are now colder above the insulation, increasing the risk of condensation and mould growth. To mitigate the condensation risk, a vapour control layer should be considered between the insulation and the internal linings. A small change to the window R value means manufacturers are scrambling to adopt thermally broken systems. This has put the industry under pressure and lead times have increased.

One has to wonder, if we are going to change something, is it better to creep slowly towards our target adjusting each year for the next 12 years? Or do we take a leap of faith? A paradigm shift requires a mindset change, we need to celebrate the achievements that exemplify our goals. If we keep celebrating sprawling single-storey homes that have unknown energy demands, huge footprints and no regard for efficiency, how can we move towards being a country that takes its commitment to the Paris Treaty seriously?

MBIE consulted on whether to change the H1 requirements and the results were interesting. They offered 4 options, they can be summarised as Status Quo (do nothing), go halfway to international standards, comparable to international standards, or going further than international standards.