Sales data shows that the use of air-to-air heatpumps in New Zealand houses is rapidlyincreasing. This rapid uptake will lead to newenergy and peak power demands on theelectricity supply system. Recent monitoringwork lias found solid fuel burners provided 56%of home heating energy while only 24% waselectricity. Heat puinps are therefore inainlydisplacing non-electric heating, and this mustultimately require additional electricitygeneration, transmission and distributioninfrastructure. Patterns of use will be critical tothe long-term impact. An August 2007 nationalsurvey of 3,407 randomly selected housesobtained data on occupant heating patterns and,if present, the use of lieat pumps. It found that19% of existing houses and 45% of new houseshave one or more heat pumps. These resultswere compared with measurements from theHousehold Energy End-Use Project (HEEP)which has detailed information on house heatingand heating systems. The national survey foundthat although heat pumps are promoted forwinter heating, 60% of households use them forcooling - an almost completely new suinmerelectric load. It was found that heatingschedules are longer in heat pump houses -notably over twice as many houses heat in themorning. Heat pump thermostats are also beingset to higher temperatures than previously foundin New Zealand homes.
Residential Heat Pumps in New Zealand
29th AIVC Conference " Advanced building ventilation and environmental technology for addressing climate change issues", Kyoto, Japan, 14-16 October 2008