I would assume all are sent for similar testing or comparative testing/scoring would be unscientific. @ChrisBarnes may wish to confirm that.
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Your Air Conditioner Specialist should do a survey of the area you choose to operate the A/C in and offer you the correct system for your needs.
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While that advice is 100% spot on, if I asked an A/C company that question in Melbourne 20 years ago the answer would have likely been that an evaporative system was sufficient for all but a week of the year. Climate change has resulted in higher humidity on more warm days making the evaporative systems less effective above the low 30s, let alone the odd 40+ days, now-a-day.
A refrigerated A/C system is not for everyone; the evap systems blowing in fresh air is nice yet on hot humid days Iâll take the sealed dehumidified air from my splits.
For clarity we have ceiling fans in each room, an evap system, and 2 splits providing comfort whatever comes (as long as the power stays on). I think I would be able to post the same in another 20 years should I be still be around regardless of what the climate does over the time.
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I need to get ceiling fans! I have many floor fans but they clutter up the place. For my a/c I have not gone split because where the outdoor units would have to go, theres no protection from the heat of the summer sun, which would effect efficiency, wouldnât it?
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You are lucky, Choice has reviewed these (the review outcomes are member content):
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You could get a shade put over the outside unit to stop direct heating of the unit. It must not obstruct airflow but there are a few around.
But read this on debunking the âmythâ
Direct link to the Florida Study which showed savings of shading the units were trivial
http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-302-96/index.htm
âWe conclude that any savings produced by localized AC condenser shading are quite modest (<3%) and that the risk of interrupting air flow to the condenser may outweigh shading considerationsâ
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If one is observant around larger commercial and many community developments, itâs surprising just how many have the split system outdoor unit roof mounted, in full sun on a hot tin roof. They are very adaptable.
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My brother lives in Melbourne and had an evaporative system installed more than 20 yrs agouti was fairly useless by comparison.Any closer than 20 or 30 klms. from the coast, they are fairly useless except when a dry hot wind from inland happens.
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Most modern systems are designed to cope with exposed installations, however I have had experience where room A/Cs were installed in country radio relay rooms where the condenser was facing east, the sun shone directly on the condenser effectively increasing the heat load to a level where the compressors failed.Shading the condensers solved the problem.
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The buying guides and reviews of air conditioners at Choice tend to focus on cooling. Living in the upper Blue Mountains, I found that reverse cycle split system air conditioners are highly effective and efficient for heating as well - not as romantic as a log fire but far more practical! Running costs are low especially when powered by solar panels during the day.
I installed a high wall-mounted inside unit. That is a mistake when you want heating as the thermostat is near the ceiling and not where you are sitting. Even with a 2.4m ceiling the difference between the unit and lounge chair level was found to be 5-6 degrees. Consequently, I always use a ceiling fan when heating. This creates a breeze and moving shadows. Some guests have been sensitive to one or the other.
Floor mounted units are much more appropriate for heating. The disadvantage is that they take up floor space that could be used for something else. There is little competition for space high up on the wall.
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Welcome back @MalcolmMcP
I have moved your advice into the Topic that deals with buying guidance and reviews.
Thank you for your hints, Iâm sure others will find them helpful.
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I live in a largish two storey house with ducted reverse cycle air conditioning. The power used by the air conditioner is quite significant - whether in heating or cooling mode and I would like to reduce the amount of electricity it uses.
The house is 30 years old and I have been there for 10. Somewhere between 10 and 30 years ago, the original equipment was replaced, leaving the ducting and outlets intact.
Would upgrading the unit to a new one be more energy efficient?
Using it less and adjusting the thermostat are effective ways to reduce the power consumption. If new units are a lot more efficient, then this may be worthwhile.
Any ideas please?
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Welcome back @ShinyBlack
It may be worth having a service conducted on the unit and filters cleaned. It there is enough blockage of the fins and filters this will increase power costs as the unit will have to work harder to get the temperature control desired. If gas is low this will also impact but this shouldnât need adjusting.
In Winter setting the temp to 18 and in Summer to 24 are great ways to reduce power consumption.
Putting heavy curtains over windows to reduce loss of efficiency through the transmission of heat and cold through the glass can also help. Also ensuring that windows and doors to the outside are well sealed is another way to reduce wastage of power.
If your current system is an inverter one then savings gained by installing a newer one will probably be less than the cost of the new product unit cost even for 10 or 15 years of use.
This may even hold true if changing from a non inverter to inverter unit.
I assume that your return filters are cleaned regularly to keep build up as minimal as possible, however if not this will have a further impact on efficiency.
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I support looking at such passive measures. Also consider external shading on windows that get the sun and roof insulation. In a two storey house you may have the problem that the top floor gets too hot in summer and the bottom floor gets too cold in winter due to internal air movement. You may be able to install doors or partitions (or just close the ones you have) to reduce this.
As others have said adjusting your thermostat can make a big difference, going for 22 degrees all year round is costly.
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Itâs also worth having a thorough inspection of the ducting for leaks. The insulation of older ducting can be minimal or deteriorated. Any issues will increase losses.
If basic checks, cleaning etc per @grahroll suggestions make little difference, is there any reason to suspect the current heating and cooling unit is not working effectively?
Depending on where you are located and how cold it gets, there are other aspects that may be worth considering. A 30 year old two story house? Are you able to share some details of climate/location and house construction/insulation.
Back when electricity costs were not too important for some home owners, the simple home upgrade sold as the very best was a ducted system. Best done as part of a new build. If the home is not well insulated, any system will operate inefficiently. If you are considering substantial investment in an upgrade it is best to look at the house as a whole. The money maybe better spent on insulation and addressing other losses.
Noted (post script) @syncretic has some useful suggestions on actions worth looking at.
Our ex North Qld home as built could barely cool to 26C (our preferred summer setting) until we installed ceiling batts. The savings in electricity over two summers paid for the batts. All before the âPink battsâ program.
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I had assumed that insulation had been in place as whether suggested by our builders or not we always have had insulation installed. You are right though as many have not considered getting satisfactory insulation installed in old setups. Even insulated ducting can make a big difference if no other insulation is installed, but it is best with good cavity insulation.
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We live in an apartment with ducted air.
Works well, no significant spikes with use, happy with performance.
But for one room!
With the rest of the apartment cosy or cool, one room is always an oven or a fridge.
Canât seem to balance this.
Also we have issues about service; we own it, not the OC but advice is vague.
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There are three basic aspects to ducted.
a) the ducts placements and sizes.
b) the main air intake location
c) room aspect and insulation and windows
In most installations there is a singe central air intake for the recirculated hot/cold air. Similarly to evaporative systems that depend on open windows, ducted systems depend on the airways between the ducts and the air intake. For example, close a door to isolate the room from the intake and the ducted system ability to heat/cool that room will plummet.
If the paths from the ducts to the intake are unobstructed, filters clean, and so on, only then will starting to throttle the other ducts be rewarding. A last comment is the thermostat needs to be in a place that either is in the main room, or sometimes in the most difficult room to heat/cool - in the latter case the utility bill usually rises as the unit runs more often to suit the outlying room, and the main living areas could suffer accordingly since the outlying room âdictates the temperatureâ in a practical sense.
I hope this helps, or at least gives you some helpful ideas.
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It looks like my question has been moved into a more general discussion about air conditionersâŠ
Thanks for the reply @grahroll. As I was specifically interested in improvements of the efficiency of air conditioners in recent years, you raise a good point about inverters. I will have to check if I currently have an inverter AC unit. Do you know if they brought a significant gain in efficiency?
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Good point. A few years ago I discovered a couple of leaks and had sections of the ducting replaced as a result (damaged or incorrect diameter ducting).
The suggestions mentioned previously do reduce consumption. I am keen to reduce my hefty power bill further so am looking at all options. If 20 year old air conditioners are known to be inefficient then an upgrade of one or more components may be cost effective. Just asking the questionâŠ
Thanks for your response (and others too)!
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