7 aircon checks before buying a resale HDB flat
Treat the installed aircon as inherited equipment, not proof that the flat is ready to cool. Before resale completion, record what stays, what works, what is accessible and what a later replacement would involve.
By Team Snowflake | Reviewed by Lead Technician 25 Jul 2026
What should a resale buyer record before completion?
Record seven separate facts: what equipment is included, how each zone behaves, the service and repair history, drainage condition, service access, outdoor support condition and the documents or constraints that follow the flat.
HDB's current resale terms say its inspection is not a condition or safety assessment of fittings in the flat. The buyer remains responsible for checking the flat's condition and whether earlier works were authorised. That makes this an evidence check, not a substitute for HDB's inspection or a building survey.
| Buyer check | Evidence to record | Decision it changes |
|---|---|---|
| Buyer checkEquipment ownership | Evidence to recordIndoor and outdoor models, unit count, remotes and what the seller will leave | Decision it changesWhether the sale includes a complete working system |
| Buyer checkRoom-by-room operation | Evidence to recordWhich rooms start, respond, cool and hold operation during the viewing | Decision it changesWhether a fault appears local or shared |
| Buyer checkService and repair history | Evidence to recordInvoices, repeated complaints, gas top-ups and replaced parts | Decision it changesWhether the system has an unresolved pattern |
| Buyer checkDrainage route | Evidence to recordVisible wet marks, drain outlet, trunking route and concealed sections | Decision it changesWhether drainage needs investigation before retention |
| Buyer checkService access | Evidence to recordFilter, fan coil, trunking, ceiling panels and outdoor unit reach | Decision it changesWhether normal maintenance or replacement will disturb finishes |
| Buyer checkOutdoor support | Evidence to recordLedge, bracket, base, corrosion, vibration and clearance | Decision it changesWhether the condenser can remain safely supported |
| Buyer checkDocuments and constraints | Evidence to recordInstallation report, model records, warranties, electrical loading and flat-specific restrictions | Decision it changesWhether reuse or replacement needs further compliance checks |
Which seven checks change the retention decision?
The useful decision is not whether an old system looks tidy. It is whether its condition and installation are clear enough to retain, price into renovation planning or replace after completion.
1. Confirm exactly what remains with the flat
List every indoor unit, outdoor unit, remote and controller shown during the viewing. Match indoor and outdoor model labels where they are safely visible, then confirm in writing what the seller will remove or leave.
A system can be incomplete even when one room runs. Missing controls, mixed equipment or an outdoor unit that does not match the stated room count changes the replacement scope.
2. Run each room separately and together
A short viewing cannot prove long-term condition, but it can show whether each zone starts, responds and produces airflow. Run rooms separately, then together if the seller permits it.
A system 2 outdoor with three indoor units is an example of why model and load matching matter. That case pattern does not prove a mismatch in another flat, but it shows why counting units alone is not enough.
3. Ask for the history behind repeated work
Request servicing invoices, repair notes and warranty records. Repeated work matters more than a single old invoice because it shows whether the same complaint kept returning.
If the gas keeps running out after top up, the useful question is whether a leak was found and repaired. A top-up history alone does not prove where a leak sits or whether the current system still leaks.
4. Trace visible drainage and moisture signs
Check around fan coils, trunking joints and nearby walls for stains, swelling or fresh paint that interrupts an older finish. Locate the visible drain outlet where possible.
A drain pipe gradient lost farther along a concealed route can produce intermittent dripping. A dry viewing does not clear hidden drainage, so record uncertainty instead of treating a clean wall as proof.
5. Check whether future work remains accessible
Look for access to filters, indoor covers, ceiling panels and the outdoor unit. Built-in carpentry around a fan coil or sealed trunking can turn a minor repair into disruptive opening work.
Access is a practical constraint, not an HDB approval by itself. A contractor should inspect any route that cannot be understood from the visible layout.
6. Record the ledge or bracket condition without climbing out
View the outdoor support from a safe position. Note visible corrosion, an uneven base, rocking, loose items and blocked airflow. Do not lean out or step onto an unsafe ledge to complete the check.
An unlevel ledge base aircon pattern can cause rocking without proving compressor damage. BCA's current safety guidance says owners should have trained installers check exterior supports and repair deterioration.
7. Collect records before assuming replacement is simple
Ask for available model records, warranties and the HDB air-conditioner installation report. Form AC-02 is an installation record, not a warranty or condition certificate.
HDB publishes aircon and electrical conditions for different flat types. DBSS buyers should check their development's restrictions before exercising the Option to Purchase. HDB's resale terms call out those restrictions separately.
Which points are HDB or BCA requirements, and which are buyer practice?
HDB's resale inspection and buyer inspection serve different purposes. HDB checks for specified unauthorised works and structural concerns; it does not certify the aircon's performance, remaining life or compliance with every other authority.
HDB's current aircon guidelines govern installation conditions. BCA requires a trained installer for units installed outside or projecting from a building, and its current safety page addresses exterior supports. Checking invoices, testing rooms and photographing routes are buyer due diligence, not a statutory aircon checklist.
| Point | Status | Limit |
|---|---|---|
| PointBuyer checks the flat's condition | StatusHDB resale responsibility | LimitDoes not turn the buyer into a technical certifier |
| PointExterior unit installation by a trained installer | StatusBCA requirement | LimitApplies to exterior or projecting installations |
| PointRoom tests, photos and service-history review | StatusGood buyer practice | LimitNo single viewing proves long-term condition |
What does a pre-completion aircon check not prove?
It does not prove refrigerant condition, concealed pipe integrity, electrical safety or remaining component life. Those require access and technician testing.
The case patterns on this page show why certain observations change the next check. They do not establish the condition of a flat that has not been inspected.
- Record an uncertainty when a route, document or unit cannot be checked.
- Separate seller statements from invoices, model labels and observed operation.
- Use a technician or appropriately qualified building professional where the decision depends on hidden work or compliance.
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