Instant hot water can remove the incentive for consumers to conserve it. Photo / Getty Images
Instant hot water can remove the incentive for consumers to conserve it. Photo / Getty Images
If you are looking for a hot water heating system, you might have considered gas or heat pump technology. Andrea Stevens takes a look at these two alternatives to the old electric cylinder.
Should you choose gas or electricity for hot water heating? At first glance, gas seems like a viable option. The system is not that much dearer to install than an electric cylinder, Piped gas is supposedly cheap, burns cleanly and - if you get an 'instant' system - you won't run out of hot water.
You'll also be doing the planet and future generations a big favour - right? Perhaps not.
On closer inspection, there are some fishhooks with gas - to do with system inefficiencies and getting locked into an ultimately unsustainable fuel.
With the large Maui gas field depleted, and being replaced with several smaller fields, we've seen gas prices rise sharply - in real terms, by over 50 percent during the last decade compared with 32 percent for electricity (source: Consumer and the Ministry of Business, Innovation and Employment).
It is still a cheap fuel when compared with electricity. However, by the time you add its operating inefficiencies (you lose 20 percent of the energy as heat to the atmosphere when it is operating) and supply charges, there is not much in it.
And bottled LPG is even more expensive, partially due to extra transport costs.
If it's an instantaneous system - and this will surprise most people - another 15 to 25 percent of the energy used is cumulatively lost to the atmosphere from the 20 to 30 times the hot tap is used each day.
In addition, when you have instant hot water, the incentive to conserve water - which happens when you have a cylinder that can run out of hot water - is no longer present, and so we typically use more.
Dana Darwin, an energy consultant and the director of Energy Alternatives NZ says: "The net result is gas instantaneous systems are 60 to 70 percent efficient, and gas storage systems are 55 to 65 percent efficient (largely due to the additional standing heat losses), with greenhouse gas emissions to match."
While non-renewable gas has been falling out of favour from an environmental point of view, heat pump technology for water heating has become mainstream.
According to research by Energy Alternatives NZ, some of the heat pump systems are now the most energy efficient of all options - including solar (depending on your location) - and therefore have the lowest greenhouse gas emissions.
When well-designed and installed, they are at least three times more efficient than an electric cylinder, so you get 3kWh (of usable energy) for the price of one.
On the downside, most heat pump systems cost more to install than electric and gas cylinders, but some of the newer all-in-one models that include cylinders are only marginally more expensive than the gas alternative.
New Zealand electricity is now three-quarters renewable, so selecting an efficient 'electric' system - for example heat pumps - is seen as a good option from a carbon emission point of view.
Low-cost energy reduction options
Do your homework as heat pump water heaters vary considerably in price and efficiency from model to model. For a useful system comparison visit www.energywise.govt.nz and look up their water heating systems tool.
Before you go spending money on replacing your old hot water cylinder, do a quick test on your shower flow rate. If you can fill a 10L bucket in less than a minute, then you're using more water than you need to.
And as most of our hot water usage is in the shower, swapping the head for a low flow version, or fitting a cheap flow-restrictor, will get you saving money and greenhouse emissions immediately.
Emotion shower by Almar with the EcoAir system. Photo / Supplied
EcoAir showers by Almar
Italian shower-maker Almar has developed water-saving technology that they say reduces water consumption by up to half, depending on your water pressure.
With showers making up our biggest use of hot water, and with hot water heating accounting for about one third of the average New Zealand household's energy use, you can make savings in both water and energy with an efficient shower head.
Almar's EcoAir showerheads use the Venturi effect - or jet effect - where water comes out at a higher velocity. So pressure rather than water volume is used to wash.
In addition, they combine air with the water to get a vortex effect giving the sensation of more water, so the emotional and massaging experience of a shower is maintained
Hue by Philips includes an app that can control brightness, colour and timing. Photo / Supplied
Touted as 'the world's most connected light bulb', Hue by Philips might just revolutionise how we use and experience light. The wireless LED bulbs (only 8.5 watts) can be screwed into existing light fittings, replacing less efficient incandescent bulbs.
But that's only the start. These seemingly intelligent lamps are then controlled wirelessly via an app and remote 'bridge' linked to your WiFi modem. With the app, tune your lights to any colour, any brightness and to your timetable. Set timers so that lights often left on unnecessarily will automatically turn off.
With this control, you will only use light when you need it, and at the levels you need, reducing your energy consumption.
The Class A Monoblock power amplifier by PureAudio. Photo / Supplied
Class A Monoblock by PureAudio
A power amplifier is not the first product that comes to mind in saving energy. Aren't they all about high wattage to get a big sound?
Wellington's PureAudio tested this myth and found actual power use is often as low as 10 watts. Their Class A Monoblock power amp accommodates 65 watts, just to be safe.
When not in use, it falls back automatically to a low power standby mode. But perhaps its most striking feature is the minimal waste - and associated energy savings - in its manufacture.
The aluminium sheet used to make its outer case is structural and self-ventilated. And, most significantly, the triangular pieces of aluminium removed to create the ventilation holes, are then reused inside the product as heat sinks.
This series is made possible with funding from Energy Alternatives. To find out more about energy efficient products visit energyalternatives.co.nz.
