Published 20 April 2023

The benefits of heat pumps – the scientific proof!

The results of the most comprehensive study of heat pump use in New Zealand, or elsewhere in the world has recently been released.

The study was conducted by Motu, an independent research organisation and funded by the Energy Efficiency and Conservation Authority. It evaluated the benefits, costs, and changes in behaviour in households who had a heat pump installed in the government’s Warmer Kiwi Homes (WKH) low-income heating and insulation installation subsidy programme. WKH provides subsidies of at least 80% to homeowners who live in high-deprivation areas or hold a Community Services Card and is intended to assist lower-income New Zealanders to be able to keep their homes warm and dry in winter.

 The findings of this evaluation indicate that installation of a heat pump through the WKH programme results in householders that are more comfortable in their homes, with living areas that are materially warmer and drier in winter. On average, living area temperatures are warmer by 1.1degC during winter for a house with a WKH heat pump fitted relative to one without. Significantly, these benefits occur with a reduction in electricity consumption, with reduced electricity use being especially marked in the late afternoon and evening. Households on average used 16% less energy compared with households without a heat pump (and were likely to have been using regular plug-in heaters before heat pump installation).
 
Households that used their heat pump over summer as an air conditioner also experienced reduced living area temperatures, so increasing their comfort, with no significant increase in annual electricity consumption. When the societal benefits are matched against the overall costs for installing a heat pump in the WKH programme, the societal benefit cost ratio (BCR) component is 7.49 (i.e for every $1 of government funding there were $7.49c of benefit)! Even if more conservative assumptions are used that don’t include many of the wellbeing gains, a BCR for WKH heat pump installation is 2.15. BCRs for just the insulation component are 3.51 and 1.78. For the WKH programme as a whole, the corresponding BCRs are 4.36 and 1.89.
 
This study thus shows the effectiveness and benefits of WKH and shows that the societal benefits considerably exceed their costs. Sustainability Trust participated in this study by identifying households and installing heat pumps into homes in the study. We are truly happy to see that this study aligns with what we see every day when we install heating and insulation into homes. People are happier, warmer, drier and able to live in more rooms in their home. The fact that there is also a reduction in energy use combined with an increase in home temperature is even better! We applaud EECA and Motu for this fine piece of work and look forward to continuing to roll out Warmer Kiwi Homes for many more years to those folks in cold damp homes in Wellington and across Aotearoa.

You can read the report here and contact us today to talk to someone about insulation or heating.

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