Aircon and electrical planning are the two renovation decisions that cause the most expensive mid-project rework in Singapore homes. Not because homeowners make bad choices but because they make them too late. By the time the question of “where should the aircon go?” is asked, the false ceiling is already built, the electrical conduit is already run and the answer that would have cost S$200 to accommodate upfront now costs S$1,500 to retrofit.
This guide covers aircon and electrical planning as a single topic because in Singapore renovation they are inseparable. Every aircon point requires an isolator switch, condensate drainage and a trunking route to the outdoor compressor. All of these have to be planned before any ceiling or wall work happens. From the team at RS Carpentry, who project-manage renovation across HDB, BTO and condo homes and coordinate between carpentry, electrical and aircon trades every week.
Why Aircon Planning Has to Happen Before Renovation Starts
In Singapore almost every household has aircon and most renovations either install a new aircon system or relocate or upgrade an existing one. The aircon system affects:
- The false ceiling design: fan coil unit position determines where the ceiling recess and bulkhead go
- The electrical distribution board: an aircon system adds significant electrical load and the DB must be sized to accommodate it
- Wall routing: refrigerant pipes and condensate drain routes must be planned before walls are plastered or tiled
- Carpentry positions: a wardrobe cannot be placed where the aircon pipe runs behind the wall
The aircon installer and the renovation contractor need to have a joint conversation before any trade starts work. When this conversation does not happen, the result is a fan coil unit positioned in an awkward location, a bulkhead that is too narrow for the pipe or a condensate drain that runs through a space that has already been tiled.
Choosing the Right Aircon System for Your Flat
Singapore residential aircon systems are almost exclusively split-type systems where an indoor fan coil unit in each room connects via refrigerant pipes to an outdoor compressor unit on the aircon ledge. The main choice is between a multi-split system and individual single-split units per room.
Multi-split systems connect multiple indoor units to a single outdoor compressor. They are neater because there is only one outdoor unit and the outdoor ledge is not cluttered with multiple compressors. The trade-off is that a fault in the outdoor compressor takes down cooling in every room simultaneously.
Individual single-split systems give each room its own dedicated compressor. A fault in one system affects only that room. The trade-off is multiple outdoor units on the aircon ledge which can look cluttered and may not be permitted by some condos or HDB estates where ledge capacity is regulated.
For a typical 4-room HDB BTO, a multi-split system with three to four indoor units covering the living room, master bedroom and one or two additional bedrooms is the standard configuration. Budget roughly S$3,500 to S$5,500 for a quality system from brands like Mitsubishi Electric, Daikin or Panasonic, installed.
Aircon Capacity Sizing
Getting the capacity wrong is one of the most common aircon mistakes in Singapore renovation. An undersized unit runs continuously and never quite cools the room. An oversized unit cycles on and off too frequently and produces humidity problems because it does not run long enough to dehumidify properly.
The rough rule for Singapore conditioned spaces is one horsepower per 150 to 200 square feet of floor area for bedrooms and one to 1.5 horsepower per 200 to 300 square feet for living areas. These are starting points. Room orientation, the number of occupants, the presence of heat-generating equipment and ceiling height all affect the actual requirement. Your aircon installer should perform a proper heat load calculation rather than simply recommending the next model up in their range.
Electrical Planning: What Every Singapore Renovation Needs to Confirm
Electrical work in Singapore residential renovation requires a licensed electrician. The EMA (Energy Market Authority) licenses two categories of electrician: Licensed Electrical Workers for general wiring and Electrical Installation Licensees for larger installations. Verify that your renovation contractor engages properly licensed electrical trades.
The electrical planning conversation that should happen before any renovation starts:
- Distribution board assessment: Is the existing DB adequate for the planned load? Adding aircon to an older flat often means upgrading the DB to a higher capacity and adding RCD protection.
- Circuit allocation: Each aircon unit requires a dedicated circuit. Kitchen appliances including the hob, oven, dishwasher and water heater each require dedicated circuits. These must be planned before any ceiling or wall work is done.
- Socket point positions: Every socket, every switch, every USB point and every light point should be confirmed in writing before the electrician runs conduit. Adding a socket after the wall is tiled costs S$300 to S$600 per point. Planning it in advance costs nothing extra.
- Lighting circuit planning: Which rooms will have cove lighting? Which will have dimmable circuits? All of this must be specified before the ceiling is built.
Common Electrical Mistakes in Singapore Renovation
- Not adding enough sockets in the kitchen. A Singapore kitchen needs dedicated circuits for hob, hood, oven, dishwasher, water heater, refrigerator, microwave and at least two general-purpose sockets. Plan all of these upfront.
- Installing standard light switches where dimmers are wanted later. Dimmers require wiring that is run before the wall is plastered. Retrofitting requires opening the wall.
- Forgetting the TV point position. The TV wall position determines where the TV cable point goes. If the TV wall is built before the cable point is run to the right location, the cable will be surface-mounted or routed through a wall channel that was not planned for it.
- Aircon isolator switch positions not confirmed before tiling. Isolator switches must be accessible and within a specific distance of the aircon unit. Getting the height wrong requires rerouting cables through finished walls.
For the full pre-renovation planning checklist that prevents these problems, our pre-renovation checklist Singapore covers electrical, aircon, carpentry and permit items that should be locked before site work starts. For how electrical works appear in a renovation quotation, our renovation quotation guide explains what each line item should contain.
Plan Aircon and Electrical Before Anything Else
The sequence in a well-managed Singapore renovation is: aircon system decided, electrical scope confirmed, permits applied for, ceiling design locked and then all other trades follow. When this sequence is respected the renovation goes smoothly. When it is not, expensive rework follows.
Contact RS Carpentry for a renovation consultation that coordinates aircon, electrical and carpentry planning from the start. Browse our completed renovation projects to see how integrated trade planning produces better results than trades planned independently.
