Which is the best split system air conditioner?
You're interested in heating, cooling and dehumidifying your home with the incredible efficiency of heat pump technology. Split-system reverse-cycle air conditioning is the tool for the job...but which product should you choose?
Not sure if a split system reverse-cycle air conditioner is the way to go? Head to our article, 'How can I replace my gas heating system?'
In this article, we will save you time by providing an overview of the technology and some considerations, before recommending a good option. Then we'll finish up by giving you some pointers to assist your planning with an installer.
A quick summary of heat pump technology
Heat pumps are a familiar technology; you have one in your fridge! They extract thermal energy from the ambient air and use it to provide cooled (or heated) air.
But unlike a refrigerator, an air conditioning heat pump system has separate indoor and outdoor units. They are also capable of heating as well as cooling, which is why you'll often hear them described as, "reverse-cycle".
The brilliance of this process is that heat pumps can extract about 3 units of heat energy from the air for every unit of energy put in from electricity!
This makes the running costs for a heat pump very low compared to other technologies.
A quick summary of split systems
A "split system" configuration is composed of two units connected by insulated pipework;
- an indoor unit that blows hot or cold air;
- an outdoor unit that takes energy from the ambient air using heat pump technology.
"Multi-head" systems are similar to a split-system, but with one outdoor unit connected to two or more indoor units. This is a good option when you have two or three rooms that are reasonably close together and limitations on the available space for an outdoor unit.
Things to consider
Electrical requirements
Always start with your electrics! Single-phase power is all you need for most single (and multi) split-system air conditioners.
However, the split systems will require dedicated circuits, so you may need to create additional space on your switchboard if it is already full. Check your switchboard and factor in the cost of any necessary upgrades to add space for more circuits.
Locations
One of the benefits of split systems is that you can pick which parts of your house get heated and cooled, with each space functioning independent of the others.
If you're on a tight budget, you can focus on air conditioning only one or two areas in the home that can be comfortable spaces on particularly hot or cold days.
Have a think about which rooms you can avoid air conditioning; it'll potentially save you thousands of dollar up-front and ongoing in running costs.
Sizing
The most important factor when planning a split system install is to make sure you match the right sized unit with the room it is going in.
If you install a unit that is too big, it will run frequent short cycles to achieve the target temperature. This can result in the room getting too cold or hot, inadequate dehumidification (i.e. not drying the air enough, making the room feel less comfortable), increased power consumption and running costs, and wear and tear on the system.
Underpowered models may have to run more often at maximum output, which could dry the air too much and also lead to excessive wear.
The sweet spot is to choose a model with capacity that's either just right, or slightly more than you'll need for the room. A little extra capacity may help in extreme temperatures. For example, if the room needs a 6kW model, then go for a unit with a rated cooling capacity in the range of 6–6.5kW.
So how do you work out the right size?
Some installers and online calculators offer only a simplistic analysis and may tend to recommend a larger capacity than you really need.
Here's a ball-park so you can get a quick idea an appropriate size based on the room.
Room size | Example | Unit capacity |
Up to 20 square metres | Bedroom | 2 - 2.5kW |
20 - 40 square metres | Master bedroom, study | 2 - 2.5kW |
40 - 60 square metres | Lounge | 4 - 6kW |
60 - 80 square metres | Open-plan area | 5 - 7kW |
80+ square metres | Community hall | 6 - 9kW |
Some information sourced from: https://www.choice.com.au/home-and-living/cooling/air-conditioners/articles/what-size-air-conditioner-do-i-need
However, properly sizing an air conditioning unit should take more into account than the footprint. To get the right unit, calculations should include:
- The size of the room (length, width and height).
- The type of room (living room, open-plan living room and kitchen, bedroom etc).
- The size and orientation of the windows and glass doors (a large north- or west-facing window can let in a lot of heat in summer).
- Shading and curtains on the windows.
- Insulation of the floor, ceiling, and walls.
- The local climate.
If you want to work it out yourself, the cooling and heating load calculators on fairair.com.au, by the Australian Institute of Refrigeration, Air Conditioning and Heating (AIRAH)1, cover this level of accuracy.
A trustworthy installer should be factoring in these things when they quote you for a system so you don't have to spend time crunching the numbers. Just ask them to share their calculations.
Energy rating labels
Split-system air conditioners sold in Australia have to meet minimum energy performance standards.
When a manufacturer registers a model with the government Energy Rating system2, the air conditioner gets a star rating label for cooling and heating based on its test results against the Australian Standard for air conditioners.
You'll see the label on the model in-store or online. This gives you a quick and easy way to compare models.
The more stars, the more efficient the model and the less it should cost to run, assuming it's been correctly installed.
Even a model with one or two stars is still OK, but a model with five or six stars (or more) is clearly better, though more efficient models might also be more expensive.
Models now come with a star rating label known as the Zoned Energy Rating Label (ZERL). This shows three cooling star ratings and three heating star ratings, based on the climate zone where the unit is installed. This makes it easier to choose a unit that fits your local climate conditions.
Zoned Energy Rating Label for air conditioners (image: Department of Industry, Science, Energy and Resources).
Models manufactured before 2020 will not have a climate zone-specific rating.
Warranties
How long are you covered by a guarantee with a certain product? This can massively reduce the financial risk you are taking on by investing in a new system. Treat warranty periods as one of your most important decision-making factors.
Most established brands from budget to high-end offer a 5 year warranty. Make sure the product you are considering will at least match this industry standard.
Check what components or labour the guarantee covers. Some unit components may have a longer warranty period than others. This should be clearly outlined in the warranty terms on the manufacturer's website.
Installers
It's also worth remembering that installers will be the ones to honour guarantees if something goes wrong. Make sure your installer is established with a strong track record.
We put all our tradies through checks to make sure they are reliable. You can have a read of our check list, here, and we encourage you to use it when considering installers.
Also, make sure you get licensed tradespeople to complete the work so the install is to accreditation standards and they can issue a compliance certificate.
Depending on your requirements, the replacement may involve electrical and plumbing work and so looking for a provider that can do both will save you time and potentially money.
Which one should you buy?
Here's the thing; there's not a huge difference between the major air conditioning brands. Most of them provide a 5 year warranty and use the same refrigerants (if you're worried about environmental impact).
If you get too caught up in comparing specific products from certain brands, you'll waste countless hours wading through data tables.
Best case result? You end up with an random assortment of different sized units from different companies dotted around your home.
Instead of trying to select the perfect split system air conditioner, you'll get much better value from sizing the unit correctly, putting it in the right location, using it effectively, keeping the filters clean and getting it serviced regularly.
If you'd like help making a decision, a safe option that balances performance and price is to purchase units manufactured by Mitsubishi Heavy Industries (MHI).
MHI have dominated Choice and Canstar product awards since 2018 and a quick search for specific model numbers in ProductReview is likely to yield good ratings from a large number of customer reviews.
As mentioned, the sizing and installation of the unit is more critical than a specific brand or product. If want to work with Energy Freedom Homes, we'll help you size the right units and put them in the best locations to heat, cool and dehumidify your home. Get started by checking your readiness for one of our Home Electrification Masterclasses!
Installation tips
Hopefully, by now you're clear on the range of products that will heat and cool your home. As you start thinking about your installation and speaking to tradies, here are a couple of tips to make sure you get the most out of your split systems.
Indoor unit: wall or ceiling-mounted?
Mostly this is dictated by where you have space to put an indoor unit, but if you've got the choice, your options include being mounted:
- High on a wall so its airflow can easily blow across the room. This can work well for cooling, as the air will sink after it leaves the unit and circulate the room.
- At floor level, which can work better for rising hot air and also more directly heat the parts of the room where you'll be.
It's generally better to install an air conditioner on a longer wall of a room, and not directly above a window, but your installer should recommend the best place for your situation.
Outdoor unit
The outdoor unit of your split-system needs to be installed on a firm base or attached to a wall using sturdy brackets. It should be as close as possible to the indoor air outlet, ideally with about three to five metres of pipes between the two units.
To avoid the unit rattling when in operation, the installer should put dampers or bushings between the unit and the brackets.
Shade the outdoor part of your air conditioner from direct sunlight – for example, by installing it on a southern wall or providing an awning.
Noise should not be a concern with the compressor, but if you or your neighbours are sensitive, there are considerations that you can make for unit placement:
- Installing the compressor unit as far from the border of a neighbouring property as possible;
- If installed windward side, an acoustic screen should be used;
- Construction materials in near proximity such as fencing, other buildings, etc. can absorb noise;
- Decentralising the placement of units if you have several heat pumps being used4.
Ceiling fans
If you've got a ceiling fan that has a reverse mode, you'll be able to slash heating costs by running it at the same time as your air conditioner.
This is because it pulls the hot air down from the ceiling and circulates it around the room more effectively, requiring less time and power to reach a uniform and comfortable temperature.
Doesn't running two things end up costing more? No, because the split system (which is more expensive to run) won't have to work as hard for the same result. Fans are very energy efficient when compared to split systems3.
If you don't have a ceiling fan installed, consider getting your tradie to put one in when they install your split system.
Checks for your installers
You'll need a licensed air conditioner installer because of the gas refrigerant. Look for an installer with ARCtick approval.
As well as an ARCtick accreditation, your air conditioner installer should have an electrical qualification in order to wire your air conditioner into your home and issue a certificate of compliance after the work is done.
Many don't, but this means they'll be unable to offer a warranty on the electrical work, only the air conditioner itself.
Likewise, plumbing your air conditioner's drain into your home's storm-water system needs to be performed by a qualified plumber. Check that the installer you choose has the necessary accreditations to carry out the whole installation.
Next steps
Hopefully you're clear on the best split system setup for your circumstances.
Ready to get your split system installed? Make sure you have the right installer to get the job done. We have some advice in our 'How to find a trusted tradie' article...
...or get in touch and we can source a split system and connect you with one of our trusted tradies. Join an Energy Freedom Homes Masterclass and learn to identify your needs, gain expert installation advice, and meet trustworthy tradespeople. Check your Masterclass readiness now!
If you are all set with your planning for heating upgrades, take a moment to congratulate yourself! When you are ready to move to the next area of upgrades in your journey to an Energy Freedom Home, such as cooking or hot water, click here to head to our planning article.
The recommendations in this article come from talking with real people and communities to identify a best-fit option for a range of priorities. We also do our research; each of the above recommendations is based on ratings from Choice Magazine, Canstar, ProductReview and general consensus from the popular Facebook group, My Efficient Electric Home.
References
1 Fairair. (n.d.). Independent advice on cooling and heating your home. AIRAH. Retrieved 2023, from http://www.fairair.com.au/
2 Energy Rating. (n.d.). Energy Rating Calculator. Retrieved 2023, from https://www.energyrating.gov.au/calculator
3 Davies, L. L. (2022). Ceiling fans vs air conditioning: pros & cons. Canstar. Retrieved 2023, from https://www.canstarblue.com.au/appliances/ceiling-fans-or-air-conditioning-the-pros-and-cons/
4 Flimel, M. (2018). Potential optimisation of heat pump placement in terms of environmental noise levels. Chapter 5 pp. 153-174. In, Tea Espenson. (ed.). Heat Pumps: Performance and Applications. Nova.