which is better?

Is Ducted or Split Systems Better for a Box Hill home?

Like most of Melbourne, Box Hill can go through four seasons in a day. We Melbournians are used to leaving the house in a t-shirt and needing a jumper hours later. But once we get home, we want to be sheltered from these extremities. However, we’re often asked whether ducted air conditioning or split system air conditioning is the better choice. This is often met with, how long is a piece of string? Because the answer is much more complex than most think. 

So, let’s take a look at two of our clients in Box Hill. Let’s call them, Ben and Len. They both live with their wife and child and have begun renovating their family home. Thus, they are looking at new air conditioning. There differences? Well, Len has a high disposable income and prioritises keeping his spacious house neat and comfortable. He needs a system to heat and cool their entire Box Hill home. On the other hand, Ben lives on a budget, enjoys a small house where his family tends to congregate in specific areas. Ideally, he wants to keep their living room at a comfortable temperature.

To help them understand the pros and cons, we answered a few of questions:

What is Ducted Air Conditioning?

In short, it is air conditioning that supplies heating and cooling throughout the entire house through a system of duct work in either the floor or ceiling.

Generally, the roof space will have a central fan coil, or indoor unit, installed attached to a series of duct that transfer air into the selected rooms. Similar to split system air conditioning, it requires an outdoor unit which is usually double in size to the indoor unit. A thermostat installed in a main area of the house provides control over the system. As an optional extra, zoning can be installed to control the air flow to selected zones. (As opposed to a standard ducted system which operates throughout the entire home from one control).

What is Split System Air Conditioning? 

Split System Heat Pump Diagram for Box Hill

A split system air conditioner works through the use of two main units as well. This usually consists of an indoor wall hung unit (although floor standing is also available) which connects to an outdoor unit. The outdoor unit is responsible for drawing in the external air from the outside adjusting its temperature before sending it to the indoor head unit. From here, the air is filtered and conditioned to the set temperature before being dispersed into the living area. Each unit is measured (in kW) and specifically installed to individual rooms. This is because the internal head unit will struggle to heat or cool beyond a certain space. Therefore, the split system must be of the right kW size to work effectively in any given space, for example, a living room would require a larger unit than a bedroom and so on.

What are the Key Differences? 


Ducted air conditioning is more labour intensive to install and will take more time than a split system. It requires to be installed by a specialist technician and the homes structure must be suitable for installation. Typically, ducted air conditioning has a larger upfront cost, however you will achieve consistent, whole house heating and cooling. Similarly, the unit needs to be measured and installed specifically for the house, every installation is different and will come with a different price tag. It is best to have a free onsite inspection to see if your house is suitable.

Split systems are often cheaper to install depending on the amount you are looking to have. As they are installed one at a time, a budget can be managed by installing room by room until your house is sufficiently covered. Split system air conditioning can also be provided as a multi-head system, where multiple indoor head units are installed and connected to a large outdoor unit to reduce the machines outside the home. This would also need to be inspected for pricing in order to see what installation requirements are needed.


Split Systems run individually, hence they are running costs are cheaper than a ducted system operating the whole house. However zoning ducted air conditioning (so that you can turn it on for individual rooms) will help control where it is running and can potentially result in more efficient running costs.


Split Systems are very effective for heating and cooling individual rooms if the entire house is not in use at the same time. The rooms will need to be measured in order to determine the required kW to achieve the right amount of airflow to each room. Therefore, the larger the room, the larger the unit required. Ducted air conditioning, however, is better to cover large areas and for controlling even temperature throughout the entire house. The larger the room, the more outlets it will need to have installed to provide an even temperature.


Most modern air conditioning units are remarkably quiet these days with technology being updated yearly to indoor and outdoor units. In fact, most split system units also offer a quiet or night time mode that hushes the outdoor and indoor fan motors, perfect for bedrooms and keeping your neighbours in Box Hill happy! In fact, a noisy unit is typically an indication that there is a problem and will require maintenance.


If keeping your home visually pleasing is of concern to you then you will be pleased to know that most systems can blend seamlessly into the background. Ducted air conditioning visually consist of ceiling vents that are fairly discrete. They are relatively flat, small and are in a range of designs to suit your style. Split systems will be visible units on the wall. However, units range in size, design and colour which can be tailored to suit your walls. White, off-white, gloss, matte, or even coloured are all in the Daikin and Mitsubishi Electric split system range. Of course, both have outdoor units called compressors or condensers that are installed against a wall outside the house.


Ducted air conditioning requires a bit of space in the roof to have them adequately installed. Small roof spaces and poorly designed trusses render it impossible to install. Existing 2-Storey homes will also face issues running ducts downstairs. Without voids in place, it is impossible to run and suspend ductwork down wall cavities to the desired room. In such case, you could install a smaller ducted air conditioner for upstairs and install Split Systems downstairs. Split systems require suitable wall space to install therefore placement of the head units will need to be considered. Areas with a lot of doors and/or windows will pose a problem. Both, of course, have external units installed against an outdoor wall with copper piping, connections, and drain. These materials will be seen from outside the house.


While the extent of use and environmental factors can impact either system, including animals getting into internal systems, ducted air conditioners typically last longer. On average ducted systems properly installed by a licence technician can last around 15-20 years before any major components may need to be replaced.

Whereas, split systems installed by a licenced technician typically lasts up to 10-15 years before needing to be replaced. This is of course determined by the type of air conditioner installed and that proper maintenance and regular filter cleaning is carried out. Whereas a lack of maintenance will no doubt shorten it’s life.

Regardless of which system you choose, you need to ensure you get them regularly checked and stay on top of cleaning the filter for both units. Split system head unit filters need to be washed every few months and replaced once damage is seen. Ducted air conditioning will need their return air filter (usually located in the hallway) cleaned every few months, with the material needing replacement once damage is seen. Either unit will need professional maintenance every 2 years to clear drains and check various connections.


A lean system is a happy system! Air conditioning units that are well maintained and replaced when needed, should not pose any risk to your home. However, a poorly maintained system can become contaminated and spread illness posing many health risks. Hence, cleaning your filters regularly and having your system professionally cleaned every 1-2 years will ensure bacteria and allergens are not pushed into your living space.

Which System Should I Choose for Box Hill? 

After having the pros and cons explained, both Ben and Len understood the key differences between the air conditioning systems and could immediately see which system they wanted to install.

Len couldn’t stop raving about the value of adding ducted air conditioning to his home. He didn’t have to worry about any unsightly units, and he could confidently maintain an even temperature through his house. On the other hand, Ben was delighted to find a solution that gave him the flexibility to expand the system down the track. The split system unit was perfect for keeping their living room comfortable whole offering straight forward to maintenance.

Ultimately, whether a ducted or a split system air conditioner is better for your Box Hill home comes down to if you’re a Len or a Ben, and of course what your home will allow for.

Contact Rapid Cold today to discuss your options and our friendly staff will design a tailored solution just for you!