Heat pumps are a class of technology that very efficiently move heat from one place to another. They can pump heat from outside a space and put it inside (heating mode) or pump heat from inside a space and put it outside (cooling mode). Some can move heat in either direction depending on your setting.
Heat pumps are fairly common home appliances. Refrigerators are heat pumps that keep food cool by moving heat from inside to outside. Hot water heat pumps take ambient heat and store it within themselves, creating a supply of hot water for you to use. RCACs (Reverse Cycle Air Conditioners) can pump heat in two directions, allowing you to heat or cool your home as required.
This article also answers the following questions:
- Should I consider installing a heat pump(s)?
- Which type of heat pump should I install?
- Can I use heat pumps in my business?
Should I consider installing a heat pump(s)?
Yes. Heat pumps are the most efficient form of heating and cooling technology that exists, there are often government subsidies available for installing them, and though they can be expensive to purchase and install they can reduce your ongoing energy expenses many times over.
How efficient are they compared to other technologies?
Unlike other forms of heating and cooling that could only ever be 100% efficient (yet never are), heat pumps are ~400% efficient. This is because they only need to use a little energy to move a lot of ambient heat. In fact for every unit of energy they consume they can move ~4X as much heat to where you want it. Depending on how inefficient your current heating and cooling solution is, upgrading to a heat pump could improve your energy efficiency by as much as ~13X.
For example, consider an upgrade from a ducted gas heater to a wall-mounted, split-system RCAC. Ducted gas heaters are only ~30% efficient because of waste delivered heat, duct losses, and flue losses. Whereas RCAC are ~400% efficient because they use 'free energy' from ambient heat. Therefore upgrading from ducted gas heating to a wall-mounted RCAC will improve your energy efficiency 13.3 times over (400/30 = 13.3).
What subsidies are available?
This changes depending on your circumstances, and particularly where you live. In South Australia the following rebates are or may be available to you:
- Federal STCs (Small-Scale Technology Certificate) rebates up to $1150,
- State REPS (Retailer Energy Productivity Scheme) rebates up to $834, and
- City of Adelaide rebates up to $1,000.
Depending on your income you may also be eligible for NILS (No Interest Loan Scheme).
How can I best reduce my energy costs with heat pumps?
The most valuable uses for home heat pumps tend to be heating and/or cooling air and water. These are the greatest energy demands of the typical Australian home so efficiency gains in these areas usually offer the greatest saving potential. But you may also have other energy-intensive applications that are also worth investing in, such as heating your pool, chilling water, or even heating a sauna.
Which type of heat pump should I install?
This answer depends on your personal circumstances, but in Australia the most common type of home heat pump tends to be air-sourced heat pumps. These tend to be less expensive than other types because they are simpler to make and easier to install.
| Aussie home heat pumps | Application | ||||
| Air conditioning | Home water heating | Pool heating | Refrigeration | ||
| Heat source | Air | Common | Rare | Common | Very common |
| Water | Rare | Rare | Rare | Rare | |
| Ground | Rare | Rare | Rare | Rare | |
| Hybrid | Rare | Rare | Rare | Rare | |
Will an air-sourced heat pump still work in a cold location?
The short answer is yes, especially in a relatively warm region like Australia. Even though air might feel cold to humans it can still contain enough thermal energy for a machine to extract useful heat. Keep in mind that thermal energy only reaches 'absolute zero' at zero Kelvin (i.e. -273.15°C or -459.67°F).
High quality heat pumps can still heat a home at -24°C, though their efficiency does lower as air temperature lowers. As a rule of thumb expect a heat pump to fall below 100% efficient at around -5°C. But keep in mind that a ducted gas-fired heater is only around 30% efficient.
Can I use heat pumps in my business?
Yes. There are many applications for heat pumps in commercial and industrial settings, and also a wider array of heat sources than homes have access to.
For example, heat pumps can be used in pasteurisation, process cooling/heating, pre-heating boiler feed water, drying, and washing processes. Also, industrial processes often generate waste heat that can be captured and recycled, instead of being released into the environment and lost.