Ducted Reverse Cycle A/C - Suggestions for best bang for buck

• 

  battler on 09/01/2015 - 11:32

  IMHO, 7 zones & 7 temp sensors is overkill for a 4 bedder.

• 

  Tarnsie on 09/01/2015 - 11:47

  1 Bed1
  2 Bed2
  3 Bed3
  4 Bed4
  5 Kitchen
  6 Living
  7 TV Room.

  It would be mainly used for very hot nights but i dont want the any rooms that i am not using to be cooled since its a waste of energy/money. Sometimes 1 or both kids sleep at their grandparents house so im looking to isolate the A/C to each room. Maybe i should use 2 rooms on one zone and the other 2 rooms on the other zone.

  note: The house is not open living and is about 220sqm internal.

• 

  Tarnsie on 09/01/2015 - 11:51

  I dont mind paying a bit more for a quality system if it means less repair costs. eg I want to minimise the total costs over the life of the unit. TC = Initial Cost + Running Costs + Repairs.

  I have heard these units are pretty reliable with a low markup.
  Actron ESP Plus
  Panasonic.
  Fujitsu - Maybe???

  • 

    npc on 09/01/2015 - 12:44

    I'd suggest to exclude Fujitsu.

    • Mine failed after 5 1/2 years (half a year after warranty). Repair cost mentioned by Fujitsu was >$1000 with no guarantee that they'll fix it. Ended up investigating by myself, found the faulty part and bought it from Fujitsu for $67.
      
      • Plastic on the wired control became ugly yellow rather quickly.

    Edit: I have to say that electricity consumption of ducted aircon is well..noticeable:) But it is so much better than splits.

  • 

    ESEMCE on 09/01/2015 - 13:24

    +3

    Split system for each room.
    Probably cost the same to buy/install. Can even do it in stages to spread the upfront cost across time.

    Significantly lower running cost cause you only cool the room you're in and have the unit run at it's most efficient (ie 70%) setting to do so. Rather than 1 big unit specced to cool the entire house running at 30% speed (cause you're only activating 1 or 2 zones) which is inefficient.

    Less/easier maintenance - less, cause units only run when required, spread run hours across systems, rather than 1 big unit running for long hours. And easier cause units are at ground level.

    More reliability - if one unit breaks down, others will still work.

    • 

      teardrops21 on 09/01/2015 - 16:45

      +1

      I agree with scubacoles, my preference would be splits for the following reasons:

      • Efficiency splits are more efficient for the following reasons:

        You can turn them on and off as required, in addition you have the advantage of setting them to different temperatures for individual comfort.
        The fans on ducted units consume significant power, the fan on our ducted gas unit uses 650W (enough to power a small split system)
        The ducts on ducted units often run through hot roof spaces. Even though they are insulated there is still heat gain into the cooled air (roof spaces can often be over 50 degrees C)

        In general the smaller the compressor the higher the efficiency. Small splits system (2-5-3.5kW) these days have an EER of 5, while larger split systems have an EER of 3-4. The means even the better larger system with an EER of 4, uses 25% more power than the smaller unit with an EER 5. The difference for ducted units is even greater due to the factors explained above. Daikin even have a 2.5kW unit with an EER of 7!!!

      • Ducted units, even with zoning, produce hot and cold spots. I would think trying to set up 7 zones would be an expensive option as it would be very complex, and I would assume standard domestic controller would not be able to handle so many zones. Therefore more complex and expensive equipment would be required.

      • Another way of doing it with splits would be to use multiheaded units, that is multiple indoor head units running of a single compressor. This would reduce the number of outdoor units required.

      I hope this info helps you decide on he best system for your needs.

      As an aside note, I have stopped using my ducted gas unit and use our splits for heating, our energy costs have come down dramatically.

    • 

      npc on 09/01/2015 - 20:47

      +1

      Exactly right from the costs perspective. Ducted is very inefficient if you'd like to cool only part of the house.

      But there is a big but. Ducted is much much better in terms of comfort, can't compare it to any split system at all. You have no noise, no cold air blowing into your head, nothing is hanging on your walls. Completely different level of comfort.

• 

  Tarnsie on 09/01/2015 - 13:36

  YEs, i will have to weight it all up. In Perth the standard install cost is $600 per unit.
  The Actron goes down to 10% so if i only have one zone then 1/7 is >10% so it shouldnt be a waste

  "ESP Digital technology automatically adjusts its capacity between 10 to 100 percent."
  www.actronair.com.au/residential/ducted/esp-ultima

  • 

    ESEMCE on 09/01/2015 - 14:32

    +1

    Just cause a unit is capable of running down to 10% doesn't mean it's efficient to do so.
    Generally machines are most efficient at 70-80% load. Rarely less than 50% and rarely greater than 90%

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  Stalker on 19/09/2016 - 08:45

  Apologies for the thread revival - What option did you end up going with? Am in Perth and weighing up the same options ahead of summer. :)