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AquaFire Systems Posted by: Linda Montgomery 19 Mar 2011 7:33pm

Just wondering if anyone has any info or experience of the Aquafire systems, particularly in the south (we are in Wanaka, Central Otago)

Heating a pool Posted by: Suzanne Becher 03 Feb 2011 11:37pm

I wonder if any of the units you tested are suitable for heating a pool. If the econergy heats water to a fixed temperature of 60C it is clearly not suitable. How about the others?

Gas vs HWHP Posted by: Douglas Mein 21 Sep 2010 9:59am

You write "A good heat-pump water heater (HPWH) would reduce your hot-water bill by two-thirds" .

I assume this is compared to other electric water heating.

What is the running cost compared to gas?



Reply 1: Posted by: ADL Raymond D 29 Sep 2010 10:08pm

Annual running cost of HPWH is cheaper according to the Energywise website, check the "ongoing running costs" Graph:

Reply 2: Posted by: Free Forall 01 Jun 2011 7:46am

most comparisons of Electric/Gas/HWHP don't take into count the gas connection line charge $1 per day in auckland 0.70c Hamilton eliminating gas connection from the house can save $365 per year
controlled rate electric is often best for low hot water users HPHW is best for high users of hot water

Reply 3: Posted by: Anna Kramer 30 Jan 2012 8:28pm

Because gas water heating units are only around 85% to 90 % efficient, plus the supply charge, I don't understand why people go for this option.

new news? Posted by: Katrina Monaghan 05 Jul 2010 1:26am

Is there any more news about the Japanese CO2 pumps? This could be an amazing breakthrough for NZ. The article may also need updating, as there are two new HWHPs listed for sale on trademe in my region, one for $3,500, the other for only $3,000. At these prices, it seems like a really good option for heavy users like me.

As for the minimum safe temperature for hot water, I thought that that was well established. A breakthrough (and very simple) technology to save more energy would be to set the hot water to lower temperatures than the currently recommended 60 degrees, but with a timer causing the water to be super-heated periodically to kill any legionaires bacteria.

Noise rating a big factor Posted by: On-to-it 15 Feb 2010 3:19pm

...there is at least a 10dB difference between some heat pumps, and this makes a big difference with these things running at night. No buying decision should ignore noise as it is an expensive problem to manage.

Mains pressure? Posted by: Jayson Speer 31 Jul 2009 10:28pm

I cannot find anywhere in this article about whether the Ecoenergy can be connected to a Mains pressure hot water cylinder. I am assuming it can, but can you confirm this?
Also, as per Thomas Schneider's request, can you pls provide websites for the suppliers of each product.

Cheers :-)

water heating refrigerators Posted by: Harping Bowker 23 Jul 2009 8:33pm

Refrigerators, freezers, (& heat pumps in cooling mode) produce heat, can that heat be used to heat the hot water cylinder?

Why not a fridge freezer linked to a hot water supply?

Should external heat pump units be south facing in the summer (when cooling) and northfacing in winter (when heating)?

Timers Posted by: Stetsun 17 Jul 2009 9:08pm

Provided a suitably sized hot water cylinder and Hot Water heat pump are used a considerable efficiency gain could be made by only running the heat pump at the warmest time of the day. Are the heat pumps tested fitted with such timers?