According to current NSW Health website Guidelines:

• Current works allowed in your home "repair or maintenance of air conditioning to provide heating or cooling for the household".
• Current works not allowed in your home "Installation of Air conditioning and ventilation inside the home is not allowed unless it is urgently required for the health and safety  of a person in the home."

Staff are also subject to adhere to the following while working indoors within Greater Sydney and in LGA's of Concern:

• Facemasks, social distancing and sanitisation
• No more than 2 people working in an indoor area at the same time
• A resident must stay in a separate indoor area while work is being carried out

An Air conditioning system works by removing heat (hot or cold air) within a space by drawing the ambient air through the return air intake of the unit. The ambeint air is drawn in by the fan, this ambient air passes over the indoor coil of the unit and is then distributed back into the space. 

The Indoor coil contains the Refrigerant gas which is pumped through the Indoor unit coil, outdoor unit coil (condenser) and compressor system. The refrigerant gas being pumped through the system by the compressor invloves the the transfer of heat from the inside of a building to outside. 

For example, while the system is set to cool, The refrigerant gas running through the Indoor coil is cold. Therefore the warm ambient air has heat removed by passing over the cool coil. This cooler air will reduce the temperature within the space. This process is reversed in order to heat a room using the same Air Conditioning system

What is Reverse cycle Air conditioning? 

Reverse cycle Air conditioning system offer both heating and cooling to provide the best year round climate control within your home. Reverse cycle cycle systems absorb outdoor air and use refrigerant gas to cool or heat the air within the space. 

 How does Reverse cycle Air conditioning work?

Reverse cycle air conditioning systems remove heat, dehumidify and filter the ambient air with your home in Summer and winter. 

In Cooling mode the system will absorb heat from the air inside your home and pump it outside, leaving your home cooler. Reverse cycle systems can operated with external conditions up to 50 Degrees.

In Heating mode the system absorbs external heat, the refrigerant is pumped through the system by the compressor warming the refrigerant up. This process pumps the warm gas through the coil of the indoor unit usig the fan to distribute warm air into the space. 

The cost to install Air conditioning in your home will depend on the following considerations:

• Type of system ie: Wall mount split, Ducted system, Bulkhead, Multi or VRV system
• Size of the overall home or specific area requiring air conditioning
• Installation constraints of each specific home or building
• Quality of Equipment and materials Customer is willing to pay for 

Typical Supply and installation costs of Air Conditioning can range from: (Ex GST)

• Split system $1500.00 to $3700.00
• Ducted system $4500.00 to $15000.00
• Bulkhead system $2500.00 to $6500.00
• Multi system $3000.00 to $8000.00
• VRV System $4000.00 to $25000.00

You may want to keep costs down by keeping the old flexible duct, however you may be putting your families health at risk. A newly installed indoor fan motor blowing more air through the existing flex, along with movement of flexible duct in a roof during installation can dislodge collected and formed dust with the existing system, blowing this into the conditioned space of your home putting your families health at risk and providing a poor indoor air quality environment.

The existing flexible duct of a previous installation will be old, possibly brittle and likely to have a low thermal insulation rating. When installing a new system - the newer fan will provide a higher and more efficient static pressure within the duct.

Generally, when looking at replacing an Old ducted system the existing flexible duct and the entire installation would be close to the end of its usable life. As higher pressured air moves though older flexible duct it can easily pressurize so much as to break existing duct taped seals, find a weak spot and create a blow out where air seeps into the ceiling space or energy efficiency lost due to lower insulation ratings. For residential applications the minimum insulation thickens needs to comply with state requirements and this can often not be met with old Flexible duct

The thicker the insulation the less efficiency is lost through the harsh temperatures within hot/cold ceiling space into the flexible duct.

It is best to replace you existing zone/ damper motors during the system replacement. Increased airflow can create more static pressure within the flexible duct requiring the motor to work harder provide more torque to open or close, this will drastically shorten the lifespan of the operating zone/damper motor proving the most cost effective solution is to replace during the system replacement.

For a system that has been installed for many years generally the motors are run via a 240v power supply, the zone/damper motors we provide are 24v and are installed with easy to use 24v plug & play type cabling. There is less power consumption with 24v option and less labour intensive. New damper barrels also have less buildup of dirt, dust accumulated over the year of operation providing improved indoor air quality.

Installation of a new zone/damper during the replacement works is much more cost effective when there is an accessible ceiling space when wiring, installation and testing can be completed without obstruction. The time taken and labour allowed during replacement is cheaper than retro fitting an existing system.

Generally each system replacement, the wiring and refrigerant pipes will need to be replaced. The older the unit the refrigerant gas, required pipe installation and copper pipe thickness needs to be changed over due to new systems not being compatible with the current systems. This is at times costly however overall a benefit to replace. The existing system is likely to be running an ozone depleting HCFC type gas which has been phased out in the industry and governments.

The pipe insulation thickness may be inadequate, damaged or have a thin wall thickness. The thinner the wall thickness the more efficiency can be lost in the refrigeration cooling/heat removal process. Current standards with thicker insulation will ensure energy efficiency. 

Replacement of existing wiring is generally required due to newer systems having different wiring/ sizing requirements. This can be from the indoor to outdoor unit interconnecting cabling and also the power supply from the property switch boards dedicated AC circuit to outdoor unit and Zone motors. 

Current wiring codes require all dedicated AC power circuits to wired into switch boards to have a residual current circuit Breaker with overcurrent protection (RCBO) type breaker. This is the current electrical code requirements with majority of installations over 3-4 years not having an RCBO breaker installed within the property switchboard.

Each system will have an existing condensate drain from the indoor units within ceiling space to gutter, Down pipe or plumbing pipe can very likely have built up dirt/dust causing a slimy blockage in the pipe. This has the potential risk of harmful bacteria for the indoor air quality.

With the slimy build up within the pipe it caused a reduction in the internal area of the pipe. This can lead to blockages and drain leaks within the roof space - leading to ceiling damage. New drainsare recommended to be run with clean, clear internal pipes with added fall to drainage providing minimized chance of blockages.

If condensate drainage is deemed adequate and the installation can be re used, the minimum best practice is to blow the line out with a high pressured air compressor.

The existing grills installed for an existing ducted system can be left or replacement based on a few different reasons. 

Your existing grills will more than likely be of a metal or aluminium construction so longevity of the grills construction would generally not be an issue, however age and quality of the powdercoating finish can discolour grills and potentially crack at manufactured joints. This being the case we recommend replacing grills. 

In addition, existing grills may not be of the required size for design of new systems. Flexible duct connection sizes may be too small therefore needing to increase ceiling cut out sizes and larger grills installed. 

For the Return Air grill, we recommend a new grill to be installed on each installtion. This is due to replacing the Return air Filter and ensuring that the filter media (material) is new and will provide maximum efficiency in catching airborne particles while system is operating.