Air conditioning. Apples or Oranges?

Dry bulb. Wet bulb.  Constant zone.  Kilowatts.  Registers.  One phase.  Three phase. Unfazed.

Apologies to the poor heating/cooling specialist who tried to explain to me on the phone how the innards of our future air conditioning system could be concealed in our house.   “Do you mind putting something on email so I can think about this later?” I said.

The air conditioning needs to be considered now, so that the builders can plan for the slab penetrations.  I have two quotes so far and another on the way.  So far I have one quote for apples and one quote for oranges.  The first quote, lets call that the apples, warned me against quotes for oranges, but quite frankly, I’m leaning towards the oranges. The “apples quote” is a two-unit system. Mitsubishi.  Probably it could keep our large house with it’s big open spaces at a constant temperature year round.  This quote is $60 000.  Startling, even before you consider running costs, which I am told could be up to $6 per hour.

The supplier of the “oranges” came recommended to us by fellow canal dwellers, already an advantage.  The “oranges quote” is for just a single unit system, with brand options including LG, Mitsubishi and Fujitsu.  This quote is about $15 000, depending on the brand.

Perhaps a single unit system will struggle to cool our large house on some of Mandurah’s hottest days.  Mandurah has a subtropical climate with an average of 9.5 days per year at 35 degrees celsius or hotter and 46 days at 30 degrees celsius or above.  But we are not wilt-in-the-heat kind of people, and we are going to have a swimming pool.  In Winter, it never gets below zero and we do own jumpers.

Calling all Mandurah double story house dwellers, please tell me if your A/Cs are apples or oranges.

No need for air conditioning  in this cave-like house with window openings set high.

No need for air conditioning in this cave-like house with window openings set high.  Photo from Architizer.

Edit.  The 3rd quote has just arrived.  2 unit system – Daikin.  $27 000.  Could it be a lemon?


10 thoughts on “Air conditioning. Apples or Oranges?

    • Thanks Matt. Do you have reverse cycle A/C? If so, how many kW is your unit? Do you use yours mostly for cooling or heat? You can probably tell that I’m a bit mixed up with all this.

  1. I think the oranges quote sounds good. I have had a Daiken unit installed in our 400m2 double storey house and it works great. Heats the house very well. I am not sure what it is like in summer yet, but I dont think it will be an issue. $60,000 for an airconditioning unit – this is absurd. I think Mat is a little off the mark with the airconditioning quote. I think if someone quoted me $15,000 for airconditioning for a two bedroom apartment I would fall off my chair. We had ducted Fujitsu fitted in our last house – 3 years ago. House size was 260m2 and it was $9,000 with 5 zones.

  2. I’m throwing in a pineapple – we are installing a ground source heat pump (borehole) which is capable of heating or cooling… Expensive. Not that common in the UK yet but nearly everyone in Scandinavia use them…

    • Good on you SBH. A nice environmentally friendly option, especially in your chillier climate. I don’t think it would be worthwhile for the kind of A/C usage that we anticipate. We lived in Mandurah for many years without any A/C and I hope that we’ll only use it in our new house on those 9.5 really hot days per year. I also suspect that our site on the canal may not be suited to housing such a unit.

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