Ask most Kiwis if they're eager to receive their next power bill and you'll likely hear a resounding "no". But Mike Phipps isn’t most Kiwis.
That’s because he has recently installed a hot water heat pump in his Tauranga home, an ingenious appliance which cuts the cost of water heating significantly – reducing electricity used by 65-70%, according to the Energy Efficiency and Conservation Authority (EECA).
Phipps, a technical consultant, had the hot water heat pump installed in early February and his expectations fulfilled when his first power bill arrived. “Our bill comes in on the 22nd of every month, so this was just a part-saving – and showed me that our electricity usage was down $70 from $293 to $223,” he says.
“When I researched these things, I realised they could reduce your water heating costs by up to 80%. That first bill suggests it’s on the way to achieving that, or something near it. In terms of average kilowatts used per day, it was down to 10 compared to 24 for the previous bill.”
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He is expecting, he says, to save between $100-$120 a month from the new device.
A hot water heat pump works much like the conventional heat pump common in New Zealand living rooms. It extracts heat from the surrounding air but, instead of sending out that heat into a room, stores it in a hot water cylinder ready for use.
Phipps says he wanted one after his Christchurch-based brother installed one some time ago and said it significantly reduced his power bills during that city’s sometimes harsh winters.
“We are not far off retiring and we wanted to control our overheads for the day when our income is more limited,” says Phipps. The upfront cost of his hot water heat pump plus installation came in at about $6900, he recalls.
With monthly savings of around $120 (or $1440 annually), the investment should pay for itself in four to five years – but the next 10 years will potentially save over $14,000.
Gareth Gretton, EECA’s Lead Advisor Research, Evaluation and Insights says this is a great example of the potential savings homeowners can get from hot water heat pumps. Not only are they more efficient than traditional electric hot water systems, they also outperform gas water heating – and are over six times better when it comes to CO2 emissions.
“We are so lucky in this country to have renewable energy in hydro-electric power, geothermal power, wind power and solar power; it makes sense to take advantage of it with technology and appliances that harness these savings.”
Gretton modelled the energy cost savings of hot water heat pumps and other efficient appliances for the Gen Less home energy savings calculator, and says that the average New Zealand household could save around $1000 a year by switching to more efficient options for things like heating, hot water, cooking and driving.
“Even though the installation costs of a hot water heat pump are much higher, they are about a third of the cost to run and about three times better in terms of emissions than a traditional hot water cylinder system,” Gretton says.
It’s important, he adds, to take a good look at the efficiency of different hot water heat pumps, as it does vary. Some are also better than others at maintaining their efficiency in colder climates such Otago and Southland.
Gretton says hot water heat pumps make a big contribution to an environmentally sustainable home. “We strongly suggest people install them in new builds, when they are doing renovations, and as their old water heaters die. That’s because 42% of hot water systems in New Zealand are already over 10 years old and generally have a 15-year life span.”
Phipps says there is a lack of awareness of hot water heat pumps in New Zealand. “I couldn’t find anyone who knew much about them at first. Everyone wanted to talk solar.”
Gretton makes the point that solar and hot water heat pumps can work together to create even more savings for householders and that awareness is increasing as people realise that hot water heat pumps can also be controlled remotely and programmed for maximum savings.
There are about 12,000 hot water heat pumps in New Zealand at present, with about 1500 added every year – a low figure compared to the huge pick-up in the US and Australia, the latter of which has around 500,000 installed and is adding about 100,000 a year.
“They are simple and easy; ours was installed outside the house,” says Phipps. “My wife is happy because we have much more storage space; our linen cupboard and wardrobes have been re-shelved. As for me, I’m really anticipating our next power bill.”
To calculate how much your household could save with a hot water heat pump, visit genless.govt.nz.
