What are the HDB rules for installing an aircon?

HDB aircon installation rules at a glance

Under HDB's renovation guidelines for air-conditioner installation works, flat owners are responsible for the proper installation, safety and stability of their aircon. A BCA-trained air-conditioning condensing unit installer must do the work, and you submit an installation report to the HDB Branch within 14 days after installation. The location and installation method, including the condensate pipe, must follow HDB's approved locations and methods, so check with your HDB Branch if you are unsure.

Aircon ledge and bracket rules

The HDB aircon ledge is only for the condensing unit, and condensing units cannot be placed along the common corridor, according to HDB's installation guidelines. In flats with a 40 amp main switch, or flats upgraded under the Main Upgrading Programme (MUP) or Home Improvement Programme (HIP), an aircon on an existing or new 15A power point or 20A isolator needs no permit, subject to these limits:

• Running current restricted by a 20A double pole isolator or 15A power point.
• A maximum of 2 split-type condensing units.
• A maximum weight of 110kg per wall panel.
• Only 1 wall-mounted condensing unit per wall panel.

HDB's guide to maintaining air-conditioners shows that in flats with an aircon ledge, the split unit's condensing unit goes on the concrete ledge. It also asks you to check that each HDB aircon bracket sits on a concrete or brick wall only, not a timber frame, and is stainless steel and free of corrosion and rust.

Drainage and piping routes

HDB's aircon installation guidelines say all aircon piping must run internally, pipe joints must be insulated and condensate must discharge into a floor trap in the flat. Hacking through reinforced concrete is not allowed, the unit must not cause vibration in the building, and the condensing unit needs rubber padding at its base.

The National Environment Agency (NEA) says trays or receptacles should not be placed under or on any aircon unit. If a tray is needed for other issues, NEA says to install HDB's patented aircon tray and still check it for chokes at the drainage point. If your unit drips, see our page on aircon leaking water.

Permits and the electrical supply

Before installing, the owner and installer must check that the total running current of the condensing units does not exceed the approved electrical rating, according to HDB's aircon guidelines.

HDB's electrical works guidelines say a new 15A power point or 20A isolator needs an HDB permit in flats with a 30 amp main switch. Blocks completed since 1994, and flats upgraded under MUP or HIP, have a 40 amp main switch and need no permit to install an aircon. A 20A isolator is only allowed for aircon installation.

Electrical work at home should be carried out or supervised by a Licensed Electrical Worker (LEW), according to the Energy Market Authority (EMA). EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. You can compare HDB electricians in the directory.

Where a permit is needed, HDB's renovation permit page says your Licensed Electrical Worker may apply for the Electrical or Air-Conditioner Installation Permit for you, and you proceed only after it is granted. To check your job, try the renovation permit checker or read our guide to the HDB renovation permit.

Keeping it safe after installation

HDB's home care guide asks you to inspect your aircon regularly, checking the brackets, leaks and condensate piping. Have the condensing unit serviced regularly by a licensed service provider, and ask whether its brackets need replacing because of rust and corrosion. Flat owners face penalties for improper installation and if a unit or its supports fall for lack of maintenance.

Under HDB's installation guidelines, you must also keep the external wall free of stains, maintain the unit to avoid nuisance to neighbours and attend to any nuisance. Otherwise, HDB may ask you to stop using or remove the condensing unit. To plan regular upkeep, compare aircon servicing prices.

When to stop and call a professional

Stop and call an aircon professional if a bracket is rusty, the unit vibrates or water drips outside the flat.

When you ask for quotes for aircon installation, check:

• Is the installer BCA-trained?
• Who will submit the installation report to the HDB Branch within 14 days?
• How will the piping run, and where will condensate drain?
• Does the job need a new isolator, and a permit?

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