Waikato Regional Council has approved a major program for its ratepayers to enable them to cheaply finance retrofitting warm dry homes through a targeted rate.  New research has confirmed programs like this will deliver wide-ranging health and efficiency benefits, greenhouse gas reductions, reduce energy poverty and enable the transition to a 100% renewable electricity system at least cost.

There has been a lot of discussion about how best to generate more electricity without increasing damaging climate emissions.  Wind, solar, and battery storage are all deservedly front of mind.  But reducing electricity demand for residential space heating through high energy efficient standards for new homes and retrofitting existing stock has been largely overlooked as an energy and climate change response.

The researchers used scenarios to quantify the potential for energy efficient buildings to reduce the seasonal variation in electricity demand in New Zealand. The results show that rapid uptake of currently achievable best-practice energy efficiency standards could reduce the winter-summer demand variation by 3/4 from business as usual by 2050.  These gains were possible even with a significant growth in housing area and increasing indoor temperatures to healthy levels.

Colder climates drive higher winter heat demand, and therefore having much more to gain from energy efficient buildings. The best practice standard could reduce overall space heating demand in New Zealand’s colder climate zones by 70% in winter months.

But even in subtropical/temperate climates found in parts of the Waikato these high energy efficiency standards can reduce winter energy demand by 50% from business as usual. In addition, warmer climates are likely to also benefit from reduced cooling in summer due to energy efficient buildings. The green line shows projected energy savings in Thames Coromandel District.

The peak winter demand which caused the recent blackout was caused mostly by the use of space heating.  This research confirms that energy-efficient programs such as Waikato Regional Council’s groundbreaking sustainable homes program is where we need to concentrate far more effort. The benefits of retrofitting existing homes through these programs is shown here-

This work by Otago University shows the role of highly energy-efficient dwellings in enabling 100 percent renewable electricity, through substantially reducing the problematic winter peak in demand.  Conserving the energy we already produce achieves multiple co-benefits including reducing emissions, better health outcomes, and alleviate energy poverty.