Getting hot water out of thin air

A heat pump water heater can help cut power bills. Photo / Getty Images

ELEMENT PROMOTION: Hot water is a big energy sink in our homes constituting about 33 per cent of the total. 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 have also become 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 per cent. In some cases it is as low as 75 per cent. These traditional forms of water heating can't advance past the efficiency ceiling of 100 per cent. The rise in power bills, particularly since the privatisation reforms of 1999 has been significant. Electricity has risen at a rate of four per cent per annum over this period and gas line charges have doubled.

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), is 380 per cent or 3.8:1. That means, for every unit of power consumed, you get 3.8 units of hot water.

Now, imagine we've connected one of these little boxes connected to your hot water cylinder. That can drop your power bill by 25-30 per cent. 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.

Doug Edgar from Hobsonville has installed the Econergy system. "We had an Econergy system fitted around 18 months ago and the savings have been phenomenal," he said.

"Considering we're a two-person household, we have experienced savings of 75 per cent on our hot water heating bill! We were regularly receiving power bills of over $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 part of a bigger picture, he added. "We've since installed 3KW of solar 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 instant access to hot water. Using an Econergy system saves about 66-75 per cent of the annual running costs for a hot water cylinder and is about 40 per cent cheaper to run than natural gas.

Normally, the Econergy heater runs off mains electricity; however it also works very well with solar electricity panels. Running the Econergy during the day off solar panels can eliminate your hot water bill all together.

With energy prices continuing to rise, Econergy is the ideal hedge against the incremental cost of heating hot water. Retrofit today and the system, with a typical return on investment (ROI) of four years on average, is a timely investment for any property.

The system is guaranteed comprehensively for six years meaning that the savings are guaranteed - there are no concerns for maintenance 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 changes in legislation.

Don't take our word for it. Parliamentary Commissioner for the Environment Dr Jan Wright in her report Evaluating Solar Water Heating wrote: "Heat pump water heaters save most electricity when it is most valuable from both an environmental and economic perspective."

Consumer NZ found the Econergy heat pump water heater "blitzed its competitors" and found 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-water-heaters to find out more.

Facts at a glance

• About 33 per cent of power bills go to hot water
• Normal hot water heaters are only 75-100 per cent efficient
• The Econergy heat pump water heater is 380 per cent efficient
• Econergy can slash 25-30 per cent off energy bills
• Cost: $4495 + installation cost
• ROI: Typically 15-30 per cent per annum but can be higher than 50 per cent
• Connects to new or existing hot water cylinders
• Performance Guarantee: Six years

Find out how Econergy can fit into your new or existing home by calling 0800 ECONERGY (326 637) or visit econergy.co.nz.

This article is an Element Promotion.