SolvedCommercial HVAC
Repair or replace a 12-year-old rooftop unit in Brisbane?
Asked by Avery Bennettin Brisbane, Queensland· 4/8/2026· 787 views
I'm in Brisbane, Queensland and dealing with a 12-year-old rooftop unit in our semi-detached home. Over the last three days, it has been cooling the space unevenly during occupied hours and we're now noticing our energy use jumped before the comfort issue became obvious.
One contractor quoted A$1,482 for repair, while another jumped straight to a A$7,760 replacement because of the age. The weather here has been dealing us hot afternoon cooling demand, so I do not want to wait too long, but I also do not want to approve the wrong scope.
If you were comparing bids on this, what would you want checked first? I especially want to know how much weight you would give to economizer settings, supply temperatures, occupancy schedules, and sensor calibration.
commercialrtucontrols
10 Answers
11
✓ Accepted Answer
We had something similar and the turning point was asking each company for the actual readings in writing instead of a verbal explanation. We had a related issue with our rooftop unit in Brisbane. Once we forced every quote into the same format, the decision got much easier because the weak recommendations stood out immediately.
Lucas Murphy·4/8/2026
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The price range alone does not tell you enough. Ask what was tested, what failed, and which assumptions are built into the quote. For a rooftop unit that is cooling the space unevenly during occupied hours, the first things I would ask for are economizer settings, supply temperatures, occupancy schedules, and sensor calibration. If the contractor is recommending bigger work, ask them to explain which measurement supports that recommendation and whether they ruled out airflow or controls first. In Brisbane, Queensland, pricing can move around, but the diagnostic process should still be clear.
32
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The price range alone does not tell you enough. Ask what was tested, what failed, and which assumptions are built into the quote. For a rooftop unit that is cooling the space unevenly during occupied hours, the first things I would ask for are economizer settings, supply temperatures, occupancy schedules, and sensor calibration. If the contractor is recommending bigger work, ask them to explain which measurement supports that recommendation and whether they ruled out airflow or controls first. In Brisbane, Queensland, pricing can move around, but the diagnostic process should still be clear.
31
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Before signing anything, I would ask the technician to show the readings and explain which number actually supports the recommendation. For a rooftop unit that is cooling the space unevenly during occupied hours, the first things I would ask for are economizer settings, supply temperatures, occupancy schedules, and sensor calibration. If the contractor is recommending bigger work, ask them to explain which measurement supports that recommendation and whether they ruled out airflow or controls first. In Brisbane, Queensland, pricing can move around, but the diagnostic process should still be clear.
29
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From a contractor side, I would not approve a major repair or replacement without test results that line up with the symptoms. For a rooftop unit that is cooling the space unevenly during occupied hours, the first things I would ask for are economizer settings, supply temperatures, occupancy schedules, and sensor calibration. If the contractor is recommending bigger work, ask them to explain which measurement supports that recommendation and whether they ruled out airflow or controls first. In Brisbane, Queensland, pricing can move around, but the diagnostic process should still be clear.
25
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From a contractor side, I would not approve a major repair or replacement without test results that line up with the symptoms. For a rooftop unit that is cooling the space unevenly during occupied hours, the first things I would ask for are economizer settings, supply temperatures, occupancy schedules, and sensor calibration. If the contractor is recommending bigger work, ask them to explain which measurement supports that recommendation and whether they ruled out airflow or controls first. In Brisbane, Queensland, pricing can move around, but the diagnostic process should still be clear.
12
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What helped us most was breaking the quote into labour, parts, warranty, and optional upgrades. The expensive bid looked very different once it was itemized. We had a related issue with our rooftop unit in Brisbane. Once we forced every quote into the same format, the decision got much easier because the weak recommendations stood out immediately.
Michelle Patel·4/8/2026
12
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If you can, ask whether they checked airflow before recommending equipment. We nearly replaced a system when the bigger issue was elsewhere. We had a related issue with our rooftop unit in Brisbane. Once we forced every quote into the same format, the decision got much easier because the weak recommendations stood out immediately.
Daniel Hughes·4/9/2026
11
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We used the directory reviews to filter out firms that were vague about what they had actually tested. That saved us a lot of time. We had a related issue with our rooftop unit in Brisbane. Once we forced every quote into the same format, the decision got much easier because the weak recommendations stood out immediately.
Harper Mitchell·4/8/2026
5
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What helped us most was breaking the quote into labour, parts, warranty, and optional upgrades. The expensive bid looked very different once it was itemized. We had a related issue with our rooftop unit in Brisbane. Once we forced every quote into the same format, the decision got much easier because the weak recommendations stood out immediately.
James Brooks·4/8/2026