Heat pumps
The recent boom in sales for household heat pumps has seen sales triple in the last five years. Over the same period, the average efficiency of heat pumps available in New Zealand has increased noticeably.
Find out here about what features to look for in a heat pump.
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How heat pumps work
Heat pumps (or 'reverse cycle air conditioners') use the same technology as your refrigerator, but in reverse to heat your home. They work by taking heat from the air outside your house and transferring it inside, using a sophisticated compressor, fan and refrigerant gases.
In New Zealand, a good quality heat pump should perform effectively when the temperature gets down to minus 15 degrees Celsius as long as it is sized and installed correctly.
Energy efficiency
A conventional electric heater will deliver 1 kW of heating for every 1 kW of electricity used.
Some heat pumps can produce up to 5 kilowatts (kW) of heating for every 1 kW of electricity they use.
This is energy efficiency at its best!
Choosing what size to buy
Some heat pumps are more efficient than others and the differences in running costs and performance can be significant.
When buying a heat pump, it is important to get one that is matched to the size of the area in your house that will be heated.
As heat pumps just move heat from outside your house to inside, they have to work harder and get less efficient as outside temperatures drop.
Heat output
Generally the heat output of a heat pump is quoted at 7° Celsius (sometimes referred to as H1).
However on a cold winter’s night it is likely to be a lot colder than that outside, so heat pumps sized for your room based on the unit’s H1 performance will struggle to warm the room up.
H2 performance
When buying a heat pump, ask your heat pump supplier to size it for your room based on the units H2 performance (this is measured at 2° Celsius).
That way you know the heat pump is going to perform well at lower temperatures. More information is contained in this EECA brochure, Choosing a smart heat pump (PDF, 178KB)
ENERGY STAR® qualified heat pumps
You could save an extra $150 a year on your power bill by using an ENERGY STAR® heat pump. Units that qualify for the ENERGY STAR mark meet strict energy efficiency guidelines - visit the ENERGY STAR website for more information.
Using your heat pump smartly
Like any heating option, heat pumps give the best energy savings when they are used smartly. We advise:
- Heat the spaces that you are actually using, and shut doors and curtains to keep the heat in.
- Don't have the temperature higher than you need it – aim for between 18°–22° Celsius while you are using a space and then 16° Celsius overnight if required.
- Learn to use the timer features so your heat pump comes on an hour or so before you get home, instead of leaving it on all day.
- Make sure your house is well insulated, otherwise you could lose up to 75 % of the heat you are paying for through your ceiling, walls and floor.
More information
- Find out more about the most energy efficient heat pumps on the ENERGY STAR website.
- EECA website publication (PDF 178KB) – For comprehensive information on choosing a smart heat pump or air conditioner.
- To get an independent idea of what the correct size heat pump for your home is, visit the Consumers' NZ heat pump calculator on the Consumer website.