Heat pump hot water systems have improved significantly in recent years after a rocky introduction in Australia that left many households wary. It’s unfortunate, because these systems are extremely economical — cutting running costs by up to around 75% compared with standard electric or LPG gas hot water systems. As with any product, paying less often means lower-quality components; bargain-basement heat pumps typically use inferior parts and will usually deliver only what their price suggests.
Through the mid‑2000s until about 2015, several major hot water brands produced heat pumps that performed poorly. Government incentives and rules that encouraged solar, gas or heat pump installations in new homes drove a rapid push to market, and some manufacturers made poor design choices that lacked basic engineering common sense.
Even now, some low-quality heat pumps are still offered to unsuspecting buyers by high‑pressure sales operations, including cheap no‑name imported units that don’t tolerate Australian conditions well. If you know that cost reflects component quality, you’ll recognise that the price gap between “no name” units and reputable brands isn’t huge, while the electricity savings from switching to a quality heat pump from a gas or electric system are substantial.
Call us on 1300 728 122 for completely unbiased, honest advice about which systems are trustworthy and which to avoid.
Below is a plain explanation of how heat pumps work and the main types available. A helpful way to think about a heat pump is as the reverse of a refrigerator: refrigerators remove heat and expel warm air, while heat pump water heaters extract heat from the air and expel cooler air. Like an air conditioner blowing warm air from its outdoor unit, a heat pump water heater blows out cool air while using the captured heat to warm water through heating plates or coils in or around the storage tank. Typically a heat pump uses about 1 kW of power compared with roughly 4 kW for a standard electric element, which is why the energy savings are so large.
Heat pump hot water systems capture ambient air heat and transfer it to the water, which is why they’re sometimes called air‑sourced solar hot water heaters. They run on electricity but are roughly three times more efficient than conventional electric element heaters. In suitable conditions they reduce energy use, cut costs and lower greenhouse gas emissions. They pair particularly well with rooftop solar PV because they draw relatively little power (generally around 1 kW versus about 3.6 kW for a conventional electric heater).
How does a heat pump work?
A heat pump operates on the same basic principle as an air conditioner or fridge, but instead of removing heat from a space it moves heat into water via pipes that wrap or sit inside the storage tank. Some models pump water through a heating plate to warm it before returning it to the tank. Electricity powers a compressor that circulates a refrigerant around the system; the refrigerant absorbs heat from the air and transfers it to the water.
The refrigerant cycle involves several steps:
– Liquid refrigerant passes through an evaporator where it absorbs heat from the air and vaporises.
– The refrigerant gas is compressed by an electric compressor, raising its temperature above that of the tank water.
– The hot gas moves through a condenser where it gives up its heat to the water and condenses back into a liquid.
– The liquid then passes through an expansion valve, reducing pressure and temperature so it can return to the evaporator and repeat the cycle.
Unlike electric resistance heaters that use electricity to directly heat water, heat pumps use electricity to operate the compressor and fan and transfer a much larger amount of heat from the surrounding air into the water, making them highly efficient. The amount of heat transferred depends on ambient temperature.
When the outside air is warmer than the cold refrigerant, the heat pump absorbs that heat and moves it into the water — the warmer the ambient air, the more efficient the system. Performance drops as outside temperatures fall, which is why heat pumps are less suitable in very cold climates. Some manufacturers now produce models that operate effectively at sub‑zero temperatures, allowing installation in sheltered internal spaces such as a large, ventilated garage.
To maintain continuous heat absorption, the evaporator needs a steady supply of fresh air; a fan forces airflow across the evaporator and expels the cooled air to atmosphere.
Heat pump water heaters come in two main configurations:
– Integrated (compact) units, where the compressor and storage tank are combined into one appliance.
– Split systems, where the tank and heat pump module are separate — like a split air conditioner — connected by refrigerant piping.
If you need a trustworthy Gympie plumber experienced in hot water systems, installation or repairs for gas and electric alternatives, we can help.
