Typically new/modern homes with pre-installed ducted reverse cycle air conditioning utilise a low profile module for the indoor unit. They mount inline with the ducting, require water drains and proximity to the outdoor unit. Larger homes may require more than one module. Homes with ducting from an older gas heated system will find the ducts are of a different profile. Older ducting may not be insulated or suited to also handle cooling with a RC heat pump upgrade. Duct insulation and condensation is for the installer to assess. Each will make their recommendations based on delivering the best system. The location of the cassette/indoor unit will vary to suit the design/features of a property.
There are also home owners with older flued outdoor gas heating with ducted systems who live further south. It may be uncommon for those wanting to upgrade to a heat pump to not want or need cooling in summer as an added bonus. It may be that one needs to look beyond the everyday installer who only knows one way? There are options for packaged outdoor units. They are not necessarily promoted whether it’s the appearance, relative size, cost, or ……?
One product - premium Daikin brand and an Aussie installer with indicative pricing. The heating capacity of the units available cover the range typical of external gas heaters. From less than 20kW to greater than 40kW. The footprint is similar in outline to some modern flued gas heaters. The packages are fully weather proof with adjacent connection flanges for outlet and return air. Important questions might include the noise level of the unit relative to local requirements and frost protection suitability for areas with below freezing outdoor temperatures. Most well known manufacturers offer models suited to more temperate climates as well as versions subject to snow and frost. Electric resistive boosting is the least efficient. The larger diameter air circulation fans in these outdoor units will be similar to those provided with older gas heaters.
Ignore the reference to rooftop. They can be mounted at ground level. Rooftop is saying they are weatherproof for the typical Aussie outdoors. Common for small businesses where outdoor space may be at a premium. The smaller 16/18kW nominal cooling/heating capacity external packaged unit is equivalent to a mid range ducted RC system suitable for a smaller home.
Hopefully sufficient background to compare further the options. Noted @acreed2002 comments on underfloor air circulation and dampness. The installer who commented on the existing ducts being too large does not make sense without further context. Possibly in comparison to how a modern ducted system is sized.
Combine that with ceiling fans, and it’d probably be a very comfortable solution. And I think the radiators do or could have built-in fans to help circulate the air.
Note that with this type of system it’s best to keep it running at a low level all the time rather than turning it off completely overnight, because it will take quite a while to heat the house from scratch in the morning.
Understood. We’ve a small system with radiators piped to a wetback with a Grundfos hot water circulation pump. Hydronics when used for heating can make use of a variety of energy sources. Using more than one option or converting is relatively straight forward in that the in home elements stay the same.
I love the gentle warmth. They are premium systems even when installed with a new build. To install in an older home, it might be a high cost solution relative to other options. Especially if one is looking to underfloor heating. For cooling I’ve no relatable experience, although some offer hydronics with a cooling option.
Being able to afford the upfront cost of conversion to all electric is one of the reasons change is being held back. It’s also a factor for rental properties, especially those in appartments or on multi unit sites. As an expense for the landlord and often limited by the design and construction decisions made for each project. The article suggests a range of savings, based on where one lives.
P.S.
Link to the full report for those with an interest in greater detail.
The reality is that many homes are not wired to be all electric and the cost of upgrading them can easily be in the $1,000s just to update the breaker box, plus wiring. Many houses around here still have old wire fuses for perspective. The costs of the appliances can pale to the immediate costs of being able to run them.
15 years ago a commercial upgrade in the CBD required a local grid upgrade, quoted at over $500,000 ‘customer contribution’ for the single feed. There are discussions about the grid being able to absorb solar inputs as well as deliver outputs, but can the ‘local grid’ cope?
The investment to go all electric seems focused rather than all-encompassing. Secondarily many of us do not have 99.99% reliable power. Not all gas appliances will run without electricity for various reasons but many will. Those having ‘friendly’ gas appliances might be able to at least cook a meal or have a cuppa and a few might even have gas fire places for heat. A small consolation when sitting in the dark.
It is not so simple as just replacing appliances. Many of us realise that yet the sell goes on expecting the grid to magically evolve as well as the economics of using it and for solar owners, feeding into it.
The ABC article relies on the source Grattan Institute report. There is an appended link to it in my prior post. It’s polite to suggest the ABC has chosen simplicity over detail if comparing the two.
A sample from the report, hopefully encouragement for all to take a more critical look.
A well placed mark, especially for those supply regions where high reliance on gas has a positive benefit in reducing peak demand on the electricity network.
The Grattan report also recognises there are different priorities and outcomes depending on which state one is in. It responds accordingly. The one detail I could not find a quick answer to is whether the analysis accounted for LPG use and numbers of homes using it. More than 2 million potentially not fully considered?
As well as the above graphic it includes tables with comprehensive comparisons of different heating options. For housing of different sizes as well as rooms of varying sizes. There’s guidance on the impact of location and home energy star rating. The information provided estimates running costs and greenhouse emissions over 10 years.
Note:
For those wondering it would be correct to question how the only wood fuel device, a slow combustion stove has been assessed. Wood burning produces slightly less greenhouse gas per kg of fuel compared to natural gas. Wood also produces less than one half the heat energy per kg in a comparison. Hence at the 60% heating efficiency indicated wood will produce approx 2-3 times the emissions of heating based on natural gas. This also excludes any additional particulate or other combustion products. The tables in the guide provide a very low relative emissions result. There’s a foot note suggesting the wood has been sustainably sourced.
I had trouble finding a home for this as it is relevant to replacing gas but also to the need for insulation and the effects of aircon with wall outlets when in heating mode.
There’s an interesting shorter topic that the Conversation article also responds to.
The OP suggested Choice might consider assessing RC Air Conditioners on how well they warmed one’s feet in heating mode.
The Conversation article offers a scientific view as to ‘why it is so’ or ‘not so’ and how to improve the outcome. It’s due to the home/room design and insulation/heat losses from the room. Useful advice for anyone choosing to convert from gas and considering a high wall mounted split system RC air conditioner.
