Ducted Air Conditioning

Hi PC friends

I need to get air conditioning to my double brick home (70 years old house), which is samall-ish area size (120m2) with raised timber flooring. The ceiling is beautiful with great heritage plastering ( people suggested horsehair corniche). House in Brisbane and it gets hot during summer and cold during winter, not to an awful degree, but I like the ability to change hot/cold home into a cosy space through AC

Few questions need your help in getting them answered or commented on:

• Ducted is more expensive than split, but it will be better as it is quieter, less outdoor units, and I don't have to take off the curtain rails to make room for the internal units (Mrs. will be disappointed too as it will ruin the house style).
• Recommended system size was 12.5Kw from multiple brands & contractors (Zones 4-6 and one contractor mentioned that they will install 9 outlets)
• Brands & costs are ranked as follows:
  • Actron ESP QUE, most appealing for the energy efficiency and Aussie made system
  • Mitsubishi Electric, 12.5Kw cost is Actron+$1k (surprising right), 10Kw is 23% less thank Actron
  • Daikin 10Kw is 34% less than Actron
• Ceiling requires insulation using R3 Polyester Batts. Air blows thru roof cavity, will insulation be useful?
• Will Spin–a–Way roof ventilators give further efficiency to the system?
• The concrete path where the unit is expected to be installed is old, sinking and may require fixing. I want to avoid thinking of it now as it will require lots of search time to decide what to do, who to assign the work to ... etc

FYI, In the distant future, we may add a second storey to the house

I am inclined to Actron, but the Mitsubishi 10Kw looks appealing too. Am I using the wrong criteria to decide?

Any help is appreciated. Share your experience with me and spread the knowledge

 

My system is Actron - it’s over 20 years old and still very good . But so are the other brands , by all reports. The Actron Que they have quoted you for is absolute top of the range you know? ... they have less expensive models that work very well .

The classic model or the ultimate model (if you want wifi control and 4 zones ) will be a little less efficient than Que but also be quite a bit cheaper

Comfort Kit Offer - Never Before Seen Pricing on ActronAir


The roof ventilators / whirlybirds are ok and they do an ok job , but unless you put several in they don’t shift a lot of air . There are some solar and electroc powered ones that obviously shift a lot Loren air , by they aren’t as cheap as the ball bearing types. I’m not saying you shouldn’t do it , but look around the area and you’ll find many houses don’t have them, so they obviously aren’t so brilliantly effective that everyone goes out of their way to put them in. They aren’t especially pricey so if they were really really effective you’d imagine they’d be on every Aussie roof ...

Insulation - always preferred for sure - especially in this country but where do you draw the line ? What about sarking as well? All these things help to varying degrees ... excuse the pun

Ducted Sounds like a lot of trouble to go to for 120m2 of living area .... especially if you will be ripping the roof off and taking the ducting out when you add another level .

Maybe do some roof insulation and install a couple of 5 or 6 kw reverse cycles .... and leave the ducted until you add the 2nd level ? I get that it’s a difficult decision because you don’t want to wall mount ... but it really is a lot of expense for ducted that may be wasted not if you add another floor ....

DO IT

 

It may cost a little more but install the ducts and outlets under the floor if you have access.

There may be some Govt incentives available for certain high efficiency ac units if none of the quotes mentioned this.

Why go for the smallest capacity unit?

Have you considered a multi-head split system solution?

Our multi-split systems are quiet - 2 X 5+kw units, 5 heads but capacity for 1 more. 3.6 m insulated ceilings. Combined with ceiling fans to move the air around.

Insulation is a must, whirlybird is a maybe but a cheap install.

 

I don't see a problem installing the ducted AC if you might build up in the distant future. Should you renovate later, you will be in a position then to improve your AC to a more efficient system when this one is many years old.

Our home is 120m2. When we purchased AC, the thought at the time was that ducted would be way over the top for a small property. I dont know your household makeup, but we can cool our entire home in Summer using two Splits, one at each end, and leaving all the internal doors open to the rooms we regularly use.

 

Quote..

Recommended system size was 12.5Kw from multiple brands & contractors (Zones 4-6 and one contractor mentioned that they will install 9 outlets)

Depending on the ceiling space the ducted system may be the easy way out--depending also on the location of the heat pump and a few other items..
Cost wise back to back wall-mounted splits would work very well ,and you would not have to cut into the ceiling grid or enter the roof ..imho..

 

We opted for individual back to back systems when renovating our house (4 small 2Kw systems for each bedroom and a 5Kw for the open space). We initially thought of single ducted system, but too expensive and too much mess up opening up the roof. After a summer it is actually much better with individual units as each room has different requirements and this works much better with individual units.

Yann