Heat pump water heaters
Heat pump water heaters absorb warmth from the air and transfer it to heat water. Hence they are also referred to as ‘air-source heat pumps’. They operate on electricity but are roughly three times more efficient than a conventional electric water heater.
These systems work in a similar way to reverse-cycle air conditioners when run on a heating cycle, but heat water instead of the air inside your home.
A heat-pump hot water system can be thought of as a type of solar water heater because the heat in the air ultimately comes from the sun. Unlike solar hot water systems, heat-pump systems don’t have an electric or gas boosting system. But they do use electricity to operate the evaporator fan and compressor when they’re heating water.
Heat-pump water heaters are normally a single integrated unit installed outside on the ground. In other cases, the unit is split between the heat-pump, located outside, and a storage tank which can be installed either outside or inside. This can be an advantage compared to a solar water heater, as collector panels do not need to be installed on the roof, making installation easier. It’s important that they are installed in a well-ventilated area, as they need access to a steady stream of ambient air when operating.
As with air conditioners, heat-pump water heaters have a fan and compressor that will make noise when the unit is operating to heat the water. This needs to be considered when they’re installed. Ideally, they should be located away from bedroom windows, and in a position that does not cause a noise issue for your neighbours.
Ask the supplier about the noise (decibel) level of the unit when you get a quote. Also ask about installation options that will minimise any noise issues.
How it works
Heat pumps are one of the most energy efficient hot water solutions. While they need electricity to run, they are roughly three times more efficient than traditional electric water heaters.
Heat pumps are only suitable in warm environments. While some heat pumps do come with boosters, if the climate isn’t suitable, there is little benefit in spending the extra money on a heap pump.
If you’re replacing an existing hot water system with the same type in the same position, installation costs are relatively low, in the range of $220 to $660. If additional valves are required, or if plumbing or electrical systems require upgrades, costs will be higher.
If you need to reposition your hot water system to a different site on the property, installation costs could be another $1000 to $2000 depending on the plumbing and electrical work required.
Changing energy type, for example, switching from electric to gas, will require additional work and cost in the realm of $1500 to $3000. If you are upgrading the size of your system, additional plumbing and electrical work may be required.
How do I choose an energy efficient hot water system?
This will depend on your energy source, household size, budget, and preference for instantaneous or storage systems. If you’re connected to mains gas and your house gets a fair amount of sunlight, the most ideal system could be a solar storage hot water system with gas boosters. If your property doesn’t get much sunlight, the next best thing is an instantaneous gas system.
There is never one model that suits all households when it comes to cutting your energy bill, but electric hot water systems have high emissions and are often considered to be the most expensive option.
How to know when your water heater needs replacing or requires a service?
What kind of hot water systems are there?
First you need to establish what kind of energy source is available to your property – Gas, Electricity or Solar, then decide which system is best for you.
Storage systems or continuous flow (known as instantaneous).
Storage SystemsWater is heated and stored in an insulated tank ready for use. Most gas, electric, solar and heat pump hot water systems use a tank.
Instant hot water heaters heat only the water required and because there is no storage tank (they are also known as tankless water heaters) so they do not experience heat/energy losses of storage systems. They operate on natural gas, LPG or electricity. Most models use gas, but electric models are available. Barry Williams
