A couple of months ago I had Air Condition Guys replace my ducted air condition - both the unit and the entire existing old ducts. I paid extra to have the new ducts rated at the maximum possible - R1.5.
Last weekend I finally got to climb into the roof cavity (ladder disappeared, took time to buy a new one) and saw that they haven’t replaced all the ducts. They left about 4 meters of old duct, they also left a strap of the old ducts between the new ducts and the existing vents in the rooms.
This means that I spend my energy on partially heating/cooling my roof cavity, and it’s not what I ordered and paid for.
I’m trying to reach out to them but so far they delay any handling by saying they can’t do anything while Sydney is in lock-down. I can get that but want to know what are my options if they don’t cooperate?
My experience with them so far wasn’t great - their installers behaved generally dodgy when they were here (you decide - is blocking my neighbour’s driveway and demanding money from him to move the car considered dodgy?) and when I gave them a low review on Google they called me to promise a couple of free services in exchange for a higher rating.
Is that considered dodgy you ask? Dodgy!!! It is criminal. If someone tried that on me I would call the police immediately. You need to get rid of this company fast, but first make them replace the old ducting.
According to my relative who is an AC and Refrig mechanic there are a few things to look out for in household installations, but most importantly after appropriate AC sizing for the need is:
Make sure the returns are adequately sized eg a 10kW needs a return area of about 1200mm X 800mm or 2 of around 600mm X 400mm (more likely the way to go as rafters are generally too close together to go for a single large return). Too small a return and the airflow back to the AC will be restricted and thus airflow back to the rooms will also be restricted. Another aspect is that if the return size is too small you will get noise at the return as the airflow is impeded and as the filters get dirtier this noise will increase as well as airflows being further restricted.
Ensure that runs of flexible ducting do not go beyond 6 metres in length each, if a run is longer than 6 metres there should be rigid ducting for the majority and only small runs of flexible to the outlets. Most households have flexible ducting throughout as it is the easy way for builders. Too much flexible ducting creates too much resistance and thus restricts airflow.
Commercially for installs engineers by and large require as part of the install that flexible runs are kept to 6 metres or less.
From the look of the photo provided by @amos they could be having runs longer than 6 metres of flexible further wasting energy and not heating or cooling as needed.
