Aircon Always High Power Use, What Am I Doing Wrong

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  Nebargains on 22/01/2025 - 10:43

  I am not sure about that though it is difficult for me personally to justify the cost right at this second, but I tell ya the industry is definitely full of shonky scammers I reckon.

  Had one door knock us recently and tell us that our neighbour was getting solar and asked if we were also interested, my wife said not at the moment and they said they would be back on X day at Y time at the neighbours house and if we were interested we could chat then and left a card.

  Come that day and time and this salesman knocks on the door and says he is here to discuss solar per the appointment lol… they literally took the previous discussion as us locking in a time for an appointment.

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    SpainKing on 23/01/2025 - 15:43

    The door knockers get paid for each appointment they set up so he was probably trying to boost his income/pad his appointment numbers

    I personally wouldn't want to go to those guys if they're employing dishonest people that lie to their own company. Door knocking is a hard job though and making ends meet can be hard so I only half blame him

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  racer1234 on 22/01/2025 - 11:06

  +1

  Buy a couple of pedestal fans and use them first if you feel hot. Aircon set on 26 cool auto. Ceiling fans at night for sleeping. Works well for me in Qld.

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  Naigrabzo on 22/01/2025 - 12:36

  For a big two storey house for example 32 squares. Your reverse cycle system will be close to 20kw in total.

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  YoursTruly on 22/01/2025 - 13:35

  1. Consider a thorough cleaning of the aircon system if it already hasn’t been done since your move in.

  2. If your house has a large facade/ surface wall/ glazing that’s west facing - consider insulating it more (along with the inner of the roof). Things as simple as more trees placed in front of the west wall does wonders to cooling efficiency.

  3. When starting the aircon - I found it makes a difference to use a vent / blow first (with windows open) to expel an held back heat inside the house. It also gives a bit of a time transition to the ac system - and makes it cool ‘better’.

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  unknown34376923 on 22/01/2025 - 14:59

  I’m planning to install a split air conditioner and heating system with one 18kW outdoor unit and four indoor units (8kW, 3.5kW, 3.5kW, and 3.5kW). Alongside this, I’ll be installing a 6.6kW solar system and a 5kW inverter.

  Any recommendations please for using solar to help heat the house efficiently in winter?

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    klaw81 on 22/01/2025 - 15:32

    Any recommendations please for using solar to help heat the house efficiently in winter?

    That's a huge open-ended question.

    Heat pumps are more energy-efficient than any other form of heating, but they're still bound by the laws of physics. Solar works much better for cooling during summer than heating does in winter, since solar output is at maximum when the most cooling is required - the coldest part of the night is the furthest from solar production.

    Here's a few points:

    1. Solar is less effective and has lower outputs during winter, so temper your expectations;
    2. Your solar system capacity is considerably smaller than your AC unit. In genuinely cold weather, it will only take the edge off your heating costs;
    3. Ensuring that your home has proper insulation in the walls and ceiling and has a good air seal at doors and windows. Use window coverings to keep the heat in, and wear appropriate clothing - these measures can be far more impactful than efficient air conditioning use;
    4. Only heat the areas that actually need to be heated. Where possible, get your rooms warm before solar production ends each day. Close doors, compartmentalize larger spaces appropriately where possible.

    My overall advice would be to spend more money on solar, insulation and other energy efficiency measures - those things work passively all year round to make your life more comfortable at no extra cost. Central heating & cooling is convenient and solves the problem, but it's effectively setting money on fire to feel more comfortable.

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      JimB on 22/01/2025 - 16:16

      great answer.

      Solar does bugger all in winter in the southern states.

      Reverse cycle is great for cooling but not very efficient for heating.

      Which city are you in unknown34376923?

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    2027 on 22/01/2025 - 17:13

    -1

    One thing to consider is the ability to offset the winter heating costs with the summer cooling costs getting reduced by solar. If your summer bills go down, then your winter bills can go up with no impact to your annual spend on electricity.

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    DiscountForThee on 23/01/2025 - 20:40

    +2

    Any recommendations

    Yeah, get a bigger solar install

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    Summoner on 25/01/2025 - 08:25

    I have 10kw solar system and a 14kw ducted aircon. The solar covers the aircon when sun is up most of the time.

    On a very cold day in winter, the solar still covers the aircon, but there arent much excess left to export when aircon is heating.

    So, considering your aircon unit is bigger than mine, you might want to consider installing a bigger solar system if you want to maximise the benefit.

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  Alzori on 22/01/2025 - 20:10

  AC units are sold on their heating/cooling capacity. Depending on the model/how new it is, electricity consumption will be 20-35% of the cooling output. Using 3kW of power when in use is typical, low even, for a whole house ducted system.

  Mine for example is a 12kW AC unit for the whole house, it uses a straight 4kW of electricity when running. Yesterday it ran flat out from about 12-8pm, and couldn't even keep the place at 25C. I'm thinking of upgrading to a 16kW+ system to cope better.

  In short, sounds like your unit is working fine. AC units just use a lot of power. Thankfully that usage usually lines up pretty well with when solar is generated. Yesterday I generated 47kWh total and used up 34kWh of that myself keeping the AC going.

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    paulusjr on 25/01/2025 - 21:14

    Its called the COP, Coefficient of performance, sounds like a ducted system being discussed, so the COP would be somewhere around 3 to 1. So if its sucking 3.5kw its output is probably 10.5k. That is REALLY SMALL for a house that is multi-storey.

    How big is the house?

    Could be undersized and therefore struggling.

    Generally Samsung is low end system for whole of house, the high efficiency systems are MHI, ME and Daikan and Panasonic.

    Also could be configured wrong, with the air sensor set wrong. e.g. they can be in the return air, or on the controller. If the controller is positioned incorrectly it might be reading no change in temp and therefore forcing the system to keep pumping at max.

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  gentlekoala5906 on 22/01/2025 - 20:43

  +1

  Btw my dudes, don't go with ActronAir their systems are the worst ever

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    paulusjr on 25/01/2025 - 21:16

    +1

    spot on.. MHI, Pana.. then ME, then Daikin in that order.. everything else… especially ActronAir.

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  Sendthegoods on 22/01/2025 - 23:06

  +1

  USE DRY MODE
  I encourage everyone that can monitor their power (solar app etc) to toggle their aircon between regular cold mode and dry mode. The power consumption can be quite drastic.

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  spurf on 23/01/2025 - 09:27

  +1

  Something is definitely wrong with your units, that is way too much usage given how you have described your house. As others have mentioned, clean your fitters. Take them out and hose the dust off and let them dry. Avoid vacuuming the filter material as it tends to make it pill. I hose from the clean side to dirty first and then use the flat spray on the dirty side at an angle to push the dirt off rather than into the filter medium. I do this on a schedule in Spring and Autumn when I'm not needing the AC. If you have access to the cavity where the ducts are running it would be good to have a look and feel for any leaks. I had a super dodgy install when they replaced my AC and there were leaks everywhere. Easy fixed using some good quality duct tape.

  I have a Mitsubishi Electric Ducted unit (PEA-RP140) which can pull 4.2kW of electricity, cooling a large 5 bedroom house, and when the internal temperature reaches the setpoint (23 degrees in summer) it uses around 150W an hour.

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    paulusjr on 25/01/2025 - 21:17

    ME will have a much better COP than the sammy. (and better overall design)

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  surg3on on 23/01/2025 - 12:39

  Realistically you might have to get the unit serviced and ask the A/C guys about the power usage.

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  figarow on 23/01/2025 - 16:33

  Aircon Always High Power Use, What Am I Doing Wrong

  Using aircon.

  Try using fans instead.

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  MrKnowItAll on 23/01/2025 - 16:39

  Here's me with the exact opposite problem. Our main area (~35sqm) is almost always hot in summer. I've replaced insulation, hosed down walls, tinted windows and even sealed off a window with insulation and fibrous cement sheets and yet it's still uncomfortably warm.
  I decided to test the main AC (9kw split system) yesterday and it's drawing just 6.5a at 17C, Cool, Boost.. that's just under 1500w when it's rated at 4400w so not even half of its rated capacity. We're suffering while the AC is being lazy. Absolutely cannot recommend Midea.

  In terms of your situation though, it sounds very much like you have an underpowered AC system (seems to be a 7kw unit based on your power consumption rates) for the space it has to cool. Only solution to that is, unfortunately, total replacement of the unit(s).

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    knasty on 23/01/2025 - 18:26

    Might be worth a service check (have you cleaned the filters)? Perhaps your unit is throttling itself back because it's already hitting its max ability to transfer heat well below the rated max power? I've got a Daikin 5kW cooling an area of almost 50sqm so it is technically undersized but it has no problem doing the job.

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      MrKnowItAll on 24/01/2025 - 13:34

      +1

      Yep, filters are cleaned as is the evaporator and condenser coils. I cleaned them with just basic soap and water and a brush to get deep into the coils. What a nightmare of a job that was on the condenser with it being so large, in a corner and just on the required 30cm from the wall, barely enough room to get a brush in there.

      I should add that we got a friend of a friend to install the unit and of the 6 units he's installed, 4 of them ice over constantly (which seems to be either from dirty filters or low refrigerant levels) so I'm beginning to suspect that it's an install issue. The fact that I put the unit into force cool mode using the button on the indoor unit which is meant to run everything at 100% and it only peaked at 2300w is a little worrying.

      After suffering through another 40-degree day yesterday, I've decided I'm doing to hire an independent and well-reviewed HVAC tech to check over everything and go from there.

      Appreciate your response as it has indeed confirmed that there's something not quite right here.

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  jtc13 on 23/01/2025 - 16:42

  Does your AC have an eco setting? I find this the best on mine as when it gets to desired temp in the room it slows down the fan and reuses the cooler air in the room.

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  hothed on 24/01/2025 - 16:50

  -1

  Get a larger solar system, then set and forget. Dont pay to import power

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    paulusjr on 25/01/2025 - 21:19

    it is running at 100% which sounds like it is, it will likely fail early so best address the issue rather than trying to get around it by increasing the solar system.

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      dufflover on 01/02/2025 - 13:47

      +1

      Not to mention the sun don't shine at night…

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  Aust on 25/01/2025 - 19:42

  These things are not cheap to run but as others have said, happy wife, happy life.
  My 12kw panasonic ducted has been on for the last 3 days as its been pretty warm in WA.
  Even at night with only 2 zones active it will still chew through 1kw an hour.
  Tuesday was a $23.10 day using 88kw with 69 on the A/C.
  My app is thorough Solar Analytics.
  https://imgur.com/a/ZgaP7gP

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  dufflover on 14/02/2025 - 15:36

  Update 14/02: Model is a Samsung Ducted 14.0kWh system (AC140HBHFKH/SA)
  https://www.samsung.com/au/support/model/AC140HBHFKH/SA/
  I haven't gone up to look at the outdoor unit yet but I reckon it would be same combo as this:
  https://shop.ptea.com.au/products/samsung-duct-s-14-0kw-ac14…

  • Have also since hosed down the air intake filter.

  • On this now cool Melb day ~24 outside I tested it for about an hour, and the second storey was still trying to pull 4kW. The lower level was a going at~2.5kW (pretty much same room temp on the panel).

  I could only see one indoor Duct S unit in the access panel, but I wonder if/where the second one is, because when running the upper storey the noise is louder and more strained compared to when running ground level.

  On YouTube people are just taking off the outside unit top cover and hosing clean the fins … can I do that? (given you know, water and electricals don't mix :P)

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