How It Works

Home heat pumps are compact sealed systems similar to a refrigerator - but unlike your fridge they can both heat and cool. Here's how.

Feel the warm air that rises from the back of your fridge. Believe it or not, that warmth is coming from the inside. An evaporator coil extracts warmth from the air inside, and transfers it out into your kitchen through a condenser coil on the back.

Heat pumps work much the same way. Two linked coils, one inside your home, one outside, circulate a refrigerant that draws warmth from the outside air and transfers it into your home.

Nothing is actually heated - there are no glowing elements - and the process is very efficient. Best of all, at a flick of the switch your heat pump can work in reverse, acting as an air conditioner to pump heat out of your home and keep it refreshingly cool in summer.

So where does all this heat come from on a cold winters morning?

Well heat is a relative thing. Someone who lives in the tropics and comes to Auckland on a hot summer's day doesn't really think it's hot as they're used to higher temperatures. Someone who comes to Auckland from Norway or Alaska in the winter doesn't think it's particularly cold. If you were standing outside at -40°C thats pretty cold but by comparrison 0°C is quite warm. There is a lot of heat in the air at 0°C and all a heat pump does is take some of that heat out of the air. So a heat pump just cools the air down outside even further thereby taking some of the heat from it. Electricity is used to move it from outside to inside you home via the refrigeration system and of course the other way around on cooling.

So you and your family can feel just right all year round.

Next page - What is an inverter.