Heat pumps
Sales of household heat pumps have tripled in the last five years in New Zealand. Over the same period, the average efficiency of heat pumps available in New Zealand has also increased.
How heat pumps work
A refrigerator moves heat from inside the fridge to the outside, keeping the inside cold. A heat pump heater uses the same principle in reverse. It transfers heat from outside the house to the inside.
The outside air gets heated up by energy from the sun every day of the year. So even when the sun is not shining brightly, or it is the middle of winter, there is still a lot of solar heat energy available.
Because heat pump systems only use electrical energy to ‘move' heat they are very efficient. They don't actually ‘make' heat themselves like normal heaters do.
Not all heat pumps are created equal
Many people think all heat pumps are very energy efficient. But the differences in running costs and performance can vary greatly.
The lowest efficiency heat pumps that are available in New Zealand are 250% efficient (give $2.50 worth of heat for every $1 of electricity used). The most efficient models on the market are just over 500% efficient. These are improving gradually as newer technologies go on the market.
On average an ENERGY STAR qualified unit can give you the equivalent of around $4 worth of heating value for every $1 spent. However, a lower efficiency unit may only give you about $3 worth of heating value for the same $1. The difference can add up to around $1500 over 10 years for a medium sized unit, assuming 8 hours of use 6 months of the year.
Choosing by labels
The energy rating label will help you compare between models and types of heat pumps. Compare the heating "Capacity output" (which tells you how many kW of heat you will get) to the "Power Input" (which tells you how many kW of electricity it uses). The higher the difference between these 2 numbers, the more efficient the heat pump is. The number of stars also shows how efficient it is compared to other models of a similar output. The more stars, the more energy efficient.
ENERGY STAR qualified heat pumps are on average 15% more efficient than non-qualified models. This saves you money on power bills and helps reduce New Zealand's energy needs.
ENERGY STAR criteria covers cooling as well as heating performance. That's important if you use your heat pump for cooling in summer as well. Choosing a less efficient model will dramatically increase your power bill over the summer months.
Check out:
- Funding available for heat pumps and insulation
- Energy rating labels
- ENERGY STAR
- Current list of ENERGY STAR qualified heat pumps
- Current ENERGY STAR retailers and where to buy
- ENERGY STAR specifications for heat pumps
Checklist for choosing a heat pump
- When buying a heat pump, make sure it's matched to the size of the area you want to heat. Also, if you live in a colder area, ask your heat pump supplier to size it for your room based on the pump's "H2" performance. This is how well it performs at 2° C, and will give you an idea of how well it will work in lower temperatures. A good quality heat pump, sized and installed correctly, should perform effectively down to minus 15° C
- To get an independent idea of what sized heat pump is right for your home, visit the Consumer website
Checklist for using a heat pump efficiently
Like any heating option, heat pumps give the best energy savings when they are used smartly.
- 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° C while you are using a space, and 16° C overnight if required
- Don't leave it on all day if you are not in. Learn to use the timer features so your heat pump turns on an hour or so before you get home, instead of leaving it running all the time.
- Make sure your house is well insulated, so that you keep the heat you are paying for in your house longer
- Clean the filter (inside and outside) regularly, as per the manufacturers instructions
- Only use your heat pump as an air conditioner if you really need to. Try opening windows and doors on either side of the house to get a through breeze. Close curtains on hot, sunny days to keep you home cool and shady.
More information
