Some articles regarding that.
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Great links @Fred123! After reading that I realise that I have a non-inverter type and could gain some efficiences by upgrading. Whether it is worth it is another question!
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They do produce savings over a non inverter but the elephant in the room is whether you have the correct capacity for the area to be cooled/warmed.
If they are both of the right capacity an inverter will save you money over the years of use expected, if you however have an under capacity unit you likely will not save.
An inverter unit can for short periods run at over capacity to about 125% or a bit higher then it runs at about 80-90% capacity to ārecoverā then if temp range not met (say as in an under capacity unit) it will return to over capacity and so on. Over capacity running is useful in circumstances of turning on initially to cool the room or warm it in the first place after which it returns to normal operation. This saves no money in an under capacity situation and in fact can cost money as a non inverter will just run at 100% (no stop or start) and the largest power cost for non inverters is the restart cost as loads are very high to start the compressor.
Thus the most important thing is to ensure you get the right capacity inverter unit for the area you want to use it for, definitely nothing too small. Going a little larger will just be more expensive to buy but shouldnāt add anything much to running costs.
My choice is to go split system, my reasons follow
Each room can be individually set for the comfort of the user so much more individual control and as no returns are required they donāt need gaps around doors to allow air movement to a return if each room is isnāt individually returned.
You size the units for the space they serve, rather than a single unit to serve all rooms
You donāt need to worry about zones and thermostat placement
You donāt need to be concerned with ducting, insulation of the roof cavity is needed regardless though whether ducted or split
You donāt have a return or returns and associated filters to be worried about, though the room units do have filters that need cleaning they arenāt an onerous task.
If using just one room then only one unit needs to be on, rather than starting a 10, 11, 12, 13 kW unit just to serve one room (remembering that it will over capacity until the room gets to the set temp) and if there is too much back pressure the ducted system will open another duct to reduce that pressure. If the thermostat is away from that room you are using then the temperature may not be regulated well for that room as the running will be based on the room where the thermostat is.
I have a 12 kW ducted unit but very seriously weighing up a change back to splits for the above reasons (we have a single return in a main hallway). We are saving up for the change.
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Lots of good reasons as you listed, and why we have installed split systems in our current and previous two homes. Inverter systems in the current.
Depending on @ShinyBlack home location, once any basic issues with the ducted system are considered and resolved: Depending on solar exposure, a Solar PV add on may offer the best return for a very modest outlay, rather than a large investment in upgrading or replacing what is still sound?
Our nominal 5kW Solar PV in SE Qld more than offsets our daily electricity consumption including air con use.
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Good advice @grahroll about correctly sizing a system. I wonāt go down the split system path though. Despite the advantages you mention, I prefer the simplicity and aesthetics of a ducted system.
We live in the outer suburbs of Sydney and solar PV is something else we are considering - in addition to or instead of any A/C changes. BTW, our average daily power usage according to our last bill was 33kWh. Over a year it would be closer to 40kWh.
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Thatās a very high daily average compared to the typical 15-20 kWh daily average. Our daily usage is less than 12kWh total. Of that approx 40% is down to the RC split systems and 10-15% our water treatment plus pumping. We do not have town water nor sewage service. Solar PV provides approx 50% of that demand. The balance is exported for feed in benefits.
For the Sydney area a 5kw solar PV based on CEC data will better 20kWh daily average over the year. 30kWh would not be unusual in summer.
A rough guess is you might need a 10kW sized system to get the maximum benefit.
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I feel that installing solar would give you a better return than what upgrading your aircon would.
Here is some info I posted in another topic regarding our experiences.
Sunboost are advertising 6.6kw systems for under $4,000 so you might recoup the cost of a system in just a couple of years.
However, upgrading the aircon might cost you half the price of a solar system but only save you a few hundred dollars annually.
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Yes it is high, so Iām sure you can see why I would like to reduce my consumption. The air conditioner is a large part of this, although getting exact figures is difficult.
Iāll see how many panels can fit on my irregularly shaped roof.
Good to have some hard numbers - thanks @Fred123
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If you are running the aircon 24/7, if possibly look a number of strings such that some face east/NE, N and NW/W. This will flatten the peak generation and reduce morning and afternoon running costs.
Also check your house is well insulated as you may have high running costs through heat/cool loss. You may find it financally cheaper to install/upgrade insulation and install a smaller PV system rather than have heat/cooling losses 24/7, substantially increasing costs when the sun isnāt shining.
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Most floor units exhaust air upwards, where wall units have variable air vanes which can be adjusted to direct air downwards to people level.
Do you have Zone control for the system if not I would suggest it may be a way of reducing the power use significantly.Zone control is where you can direct air conditioning to respective areas, by closing other unoccupied areas off.
I would look at installing individual split systems in the most used areas,This would reduce power costs greatly, and still provide comfort in areas where needed.
Hi I need help in deciding what aircon to purchase now itās a big house with exposed ceiling that are on a pitch the kitchen and dining area are big maybe 5 size master bedroom and big bedroom the lounge is massive as well with exposed beam with High pitch ceiling and 4 good size bedrooms can anyone suggest anything
Welcome to the forum Nick.
That sounds like quite a challenge in both size and geometry. I would employ a professional to advise over the design.
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Where the house is located in Australia, itās aspect and construction are all influences. As the owner are you seeking a low carbon footprint? A system that utilises mass storage of heat energy or a ground sourced heat pump might be part of the best solution. How tight is the budget, and is a trade off between lower upfront cost vs higher running costs acceptable?
There are a number of guides available on the main Choice website including,
For a non standard box style home, there is much to consider. Ducted systems vs multiple split systems. Heating only vs reverse cycle. Should the decision include upgraded home insulation, shading etc to reduce losses?
From personal experience is 26-27C in summer cool enough and 16-18C in winter warm enough might be another decision. Others would suggest 20-22C in summer and 24-25C in winter as ideal.
Certainly a lot to consider, and when you have a clearer idea of the options, best to also,
For a whole of home solution there should be no difficulty obtaining proposals from multiple installers. An independent design service assuming the budget can afford it can assist to determine what is genuinely required, prior to obtaining quotes.
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My Efficient Electric Home Facebook group has information that will be useful
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There are a number of topics about air conditioning on the Community, enough so Iāll suggest you use the Community search tool to find some that might be interesting for your situation and interests.
Welcome to the forum. I have moved your post to an existing thread where you should find relevant information.
Get a proper Air Conditioner and Refrigeration Mechanic in to assess your needs. They should check build material, building orientation, room sizes, whether insulated or not to determine the best sizing and type of unit/units ie ducted or split systems. Splits allow very personal comfort control in any room/area, ducted may be difficult with narrow or non existent ceiling spacing and also require good placement of returns. So professional advice is strongly advised, not the typical Harvey Norman etc floor salesperson.
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A split in a very large room, eg a family room, lounge room, kitchen, and diner together without walls challenges splits for comfort. At a certain floor area a split does not have the flexibility (fan grunt) to distribute cold (or hot) across it whereas ducted systems can be installed with outlets in critical places. Multihead-splits have other issues already presented in prior posts.
We have such an area and the Daikin 9.5kw is totally capable of cooling it on successive 40C+ days with the overnight lows staying in the mid-20ās (rare but that is what we installed it to deal with) but there are uncomfortable warmer and cold spots unless we run ceiling fans on med or high to help circulate the air. Conversely a split in a large walled in bedroom is brilliant, no worries.
It is more than just capacity so keeping comfort (specifically circulation) in that discussion can be easily overlooked.
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