Checklist for old AC units after moving in: cleaning, repair and replacement

When moving into a new home, the AC left by the previous occupant may have an unknown maintenance history. First record the model, usage condition and handover details, then distinguish between routine maintenance, deep cleaning, fault inspection and replacement needs. This gives a better basis than removing everything at the start.

First keep the handover and equipment details

Record the brand, model, quantity and visible installation position, and ask whether there are manuals, repair records and cleaning records. Exterior photos alone cannot confirm the internal condition of the unit, and the age of the unit is not the only basis for repair or replacement.

For rented units, first confirm with the landlord the work authorisation, equipment ownership and payment arrangement, and keep the confirmation from both sides; responsibility is still handled according to the tenancy agreement and the actual situation. Do not remove the unit, alter piping or promise that the other party will pay before confirmation.

Observe from a safe position; do not rush into prolonged testing

First check for obvious water stains, damage, unusual smells and objects blocking the air outlet. If there is a burning smell, tripping, smoke, or water near electrical appliances, do not keep using it just to test the handover; arrange a suitable inspection.

If there are no danger signs, you can check the general settings and operation according to the original user manual; do not handle unfamiliar switches, circuits or the outdoor unit yourself. Briefly producing cool air does not mean all drainage and hidden faults have been eliminated.

Dust buildup and faults require different arrangements

A clean dust filter does not mean the fan wheel and coils inside the unit have been cleaned. If there is obvious dust, odour, or an unclear cleaning history, you can enquire about a deep-cleaning assessment; however, mechanical faults, drainage connections and refrigerant system issues are not substitutes for a normal cleaning service.

If replacement is needed, also confirm the cooling capacity, outdoor location, existing piping and power supply. Do not assume the new unit can be installed directly just because of the cabinet size or because a similar unit was used before; basic installation and extra works must be clearly distinguished.

Items that need to be arranged in order

First handle safety and water damage risks, then confirm faults affecting use, and finally arrange cleaning and long-term maintenance. If renovation work is still ongoing, also coordinate dust-generating processes and the cleaning schedule to avoid immediate recontamination after cleaning.

Enquire about TimesProvide the handover condition, an overall view of the equipment, and a list of issues for each unit. Cleaning, repair, or replacement can be confirmed unit by unit, rather than applying one package to all different conditions; the actual fee and appointment are subject to confirmation.

Related reading and services

• How to compare repair or replacement
• Inspection and cleaning after renovation
• Preparation before booking cleaning