Getting hot water out of thin air
We are all familiar with using heat pumps to heat our homes – 28% of New Zealand homes have them – but most of us wouldn’t know that the basic concept can be applied to heat hot water with the same efficiency. And a very low carbon footprint.
Hot water is a big energy sink in our homes constituting about 40% of the total energy use. The trusty old electric hot water cylinder has served our needs for close to 80 years and remains the most popular way to heat water. Gas water heaters became popular from the 1990s onwards by offering ‘endless’ hot water. However these ways of heating water are inefficient – the highest conversion ratio from the fuel to the end product is 100%. In some cases it is as low as 75%. These traditional forms of water heating can’t be advanced past the efficiency ceiling of 100%. The rise in power bills, particularly since the 1999 privatisation reforms has been significant. Electricity has risen at a rate of 4-7% per annum over this period and gas line charges have doubled.
A new way to heat hot water
The best way to combat higher energy costs is by using energy more efficiently. That is the genius behind the Econergy® heat pump water heater. The efficiency ratio, or Coefficient Of Performance (COP) of the Econergy heat pump water heater is 380% or 3.8:1. That means, for every unit of power consumed, you get 3.8 units of hot water. Clever.
Now, imagine we’ve connected one of these little boxes up to your hot water cylinder. That can drop your power bill by 25-30%. And get rid of that costly line charge if you use natural gas for water heating. It is such a big change that you will instantly see a big drop in your energy bills. Add the satisfaction that you’ve done your bit to reduce power consumption and tread lighter on the planet.
Econergy delivers results for average households
Doug Edgar from Hobsonville installed the Econergy system and said, “We had an Econergy system fitted two years ago and the savings have been phenomenal. Considering we’re a two person household, we have experienced savings of 75% on our hot water heating bill! We were regularly receiving power bills of $360+ per month but after the Econergy® system was installed, we reduced that to around $180 per month for the two of us. I can only imagine the savings a family of four or more would make. The Econergy system was all part of our bigger picture [for energy saving]. We’ve since installed 3kW PV panels to further reduce our power bills.
How does it work?
The Econergy heat-pump water-heater transfers heat from the ambient air using a compressor and uses it to heat water in your hot water cylinder giving fast access to hot water. Using an Econergy system saves around 66-75% of the annual running costs for a hot water cylinder and is around 40% cheaper to run than natural gas. Normally the Econergy runs off mains electricity; however it also works very well with solar electricity panels due to the low power draw – around 900W. Running the Econergy during the day off solar panels can eliminate your hot water bill altogether!
A wise investment
With energy prices continuing to rise. Econergy is the ideal hedge against the incremental cost of heating hot water, retrofit today and the system delivers typical annual Return on Investment (ROI) of 25% on average, or a four year simple payback. The system warranty is for six years meaning that the savings are guaranteed – there are no concerns for unforeseen repair costs in the first six years. The New Zealand Green Building Council’s Homestar voluntary rating is becoming more commonly used. Eventually owners will have to declare the efficiency ratings of homes when selling them. Investing now makes sense because you are future-proofing against these upcoming changes in legislation.
Don’t take our word for it. The Parliamentary Commissioner for the Environment in the recent report “Evaluating solar water heating” said “Heat pump water heaters save most electricity when it is most valuable from both an environmental and economic perspective.” Consumer Magazine tested the Econergy heat pump water heater product, finding it “blitzed its competitors” and that “at all test temperatures it was at least three times more efficient than an electric hot water cylinder” Visit consumer.org.nz/reports/heat-pump-waterheaters to read the full report.