Warmer Kiwis Study

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Houses are warmer
Even in winter and spring
Heat pumps are worth it


Motu Research led the Warmer Kiwis Study, which focused on the heat pump component of EECA’s Warmer Kiwi Homes programme - aimed at making homes warmer, drier and healthier. EECA does this by offering grants to lower-income homeowners for home insulation and/or an efficient heater.


This was, at the time, the most comprehensive study of heat pump effectiveness in Aotearoa New Zealand homes.


EECA commissioned Motu Research to investigate the impact of heat pumps in homes with a heat pump installed under the EECA Warmer Kiwi Homes programme. Motu Research worked to determine if the health and wellbeing of the household improves because of using heat pumps. Our evaluation also grew the public evidence base about what works best to make homes warmer, drier and healthier. 


We worked directly with a group of about 160 homeowners, who received a grant for an energy efficient heating device. Motu Research collected new data on peoples’ health and wellbeing in homes, the indoor environment in homes (including temperature and humidity) and electricity consumption. We did this to investigate the actual improvements in homes achieved through EECA’s programme.


Motu Research’s work concluded using heat pumps in homes results in warmer and drier living areas through winter, and households save on electricity bills. Overall, the study’s findings show the Warmer Kiwi Homes programme is effective.


The study began in 2021. Interim results from the first winter of the study were published in January 2022. We published the final results in early 2023.


Warmer Kiwis Study Data

Here is the data dictionary, which explains which data has been collected. See information on the cohorts in the note section.


With the completion of the Warmer Kiwis Study, we have archived all the data collected in the evaluation. We welcome applications to use the data for research purposes. The data is held on Motu’s secure server as four separate stata files (one for each region of the study). Researchers are welcome to apply to Motu Research for access to the data.


A researcher's application should be headed WKS Data and be sent to info@motu.org.nz. The application should outline the research topic and methodology, any ethics approvals gained by the researchers, and who will be involved in the research. If approval is granted to access the data, we will require the data to be held in a confidential manner by the researchers and not supplied to any outside party.


Contact us

You can contact us at warmerkiwis@motu.org.nz or phone 0800 668869 (0800 MOTUNZ).


Interim Report DOI: doi.org/10.29310/WP.2022.02

Summary Report DOI: doi.org/10.29310/WP.2022.13

Full Report DOI: doi.org/10.29310/WP.2022.14


Warmer Kiwis Study: Phase One

August 2020

Download the report

EECA commissioned Motu Research to do Phase One of the evaluation. Phase One reviewed current evidence supporting the Warmer Kiwi Homes programme and proposed an approach for the phase two evaluation.


Energy Efficiency and Conservation Authority