Centralised cooling in Tengah: how it actually differs from split-unit aircon

Tengah is being built as a Smart Energy Town, a joint project between HDB and SP Group. The programme bundles centralised cooling with EV charging points and a heavy rollout of solar panels across the estate. Centralised cooling is the piece that changes what sits on a resident's ledge. It swaps an individual outdoor unit for a shared cooling supply piped in from outside the flat. For a buyer comparing two Tengah flats side by side, that single hardware difference is often the bigger gap, bigger than floor level or block orientation.

Instead of running its own outdoor condenser, a subscribed flat draws chilled water from a shared rooftop chiller. A chiller plant on the rooftop cools the water, and that water travels through pipework built into the building. Each flat's Fan Coil Unit, or FCU, draws on that supply to cool the air, the same basic job an indoor unit already does. There's no refrigerant line running to an outdoor compressor, because that compressor work happens once, centrally, for the whole block rather than once per flat. Residents can also monitor and control their own usage through an app, rather than relying on a physical meter reading alone.

The infrastructure behind this is a real, long-term contract, not a pilot scheme. HDB awarded Keppel's Infrastructure Division a chilled-water supply contract covering nine BTO projects in Tengah's Brickland, Park, and Forest Hill districts. That contract reaches roughly 10,000 households. A separate joint press release from HDB and Keppel confirms a 20-year centralised cooling contract for three Tengah BTO projects. That is a different commitment from a trial run. For a homeowner, it matters less who the contractor is, and more whether a funded operator is committed to keeping the shared chiller running for the long term.

Centralised cooling is opt-in, not a default fitted into every Tengah flat. HDB's own description of the programme is specific: residents in selected Tengah projects have the option of subscribing to it, which means neighbouring blocks in the same district can run on completely different systems. A flat viewing that assumes every Tengah block runs on centralised cooling gets the estate half right. Checking which system a specific block runs matters more than assuming based on the town's reputation. A quick way to check is asking whether the sign-up ever happened for that specific address, since centralised cooling never arrives without one.

A standard split-unit system splits the cooling work across two boxes. The indoor unit blows cooled air into the room. The outdoor condenser, usually sitting on the ledge or a compressor deck, holds the compressor that runs the actual refrigeration cycle. Centralised cooling removes the second box entirely. There's no condenser to mount, no ledge bracket to check, and no refrigerant piping running between two units in the same flat. Anyone used to checking that outdoor unit for dust, ice, or a burnt smell as a first troubleshooting step has nothing there left to check.

A Fan Coil Unit takes over the indoor unit's job and nothing else. It still blows air across a coil and into the room, the same way an ordinary indoor unit does. The coil just runs on chilled water piped in from the block's rooftop plant, instead of refrigerant compressed on-site. From across the room, an FCU and a standard indoor unit look and sound similar. The difference is entirely in what feeds the coil, not in how the unit delivers cold air.

The practical result is that an entire category of aircon problems stops applying to a CCS flat. Refrigerant leaks, compressor failures, capacitor faults, and outdoor fan motor issues are all tied to hardware a CCS flat simply doesn't have. What replaces them is a narrower, quieter set of issues confined to the FCU itself and the piping behind the wall, covered further below. That narrower list is also faster to diagnose, since fewer components means fewer places a fault can hide.

None of this hardware is something a homeowner installs or chooses. The FCU and the chilled-water piping are built into the flat as part of construction, the same way plumbing and electrical wiring already are. That's different from a resident bringing in an installer to fit equipment afterward. It's also a genuine difference from a standard split-unit purchase, where the homeowner picks the brand, the installer, and the exact placement. There is no installation quote to compare between contractors on a CCS flat, and no brand choice the way a split-unit buyer picks between, say, Daikin and Mitsubishi Electric. A CCS resident is choosing whether to subscribe to a system that already exists in the building, not choosing which hardware to buy.

Chilled water usage is billed separately from ordinary electricity, at a rate set by the CCS operator and reviewed every quarter. As at the second quarter of 2026, that rate sits at 10.00 cents per kWh before GST, 10.90 cents with GST included. Because the rate is reviewed quarterly rather than fixed for the life of the flat, a number quoted today is a snapshot. It isn't a promise about what a bill will look like in two or three years. Treating the current rate as a rough planning figure, rather than a fixed number to budget against for a decade, is the safer habit.

The FCU itself is a separate purchase from the chilled water subscription. Residents sign up for centralised cooling through a district-specific portal rather than through SP directly. The FCU unit itself is bought on top of that sign-up, not bundled invisibly into a flat's price. SP Utilities still needs to be activated before key collection, the same as any other Tengah flat. Ordinary electricity, water, and gas billing all still run through the standard SP account, regardless of whether a flat has centralised cooling.

HDB states that centralised cooling subscribers can save up to 30 percent in life cycle costs compared with a conventional split-unit system. That figure factors in the FCU's lower running load against the combined purchase, servicing, and electricity cost of an outdoor compressor over the same years. It comes from HDB's own published comparison, not from an independently audited bill. A household deciding whether to subscribe should treat it as a modelled estimate, useful for comparison, not a guaranteed number for one specific flat. The safest way to use it is as a comparison tool against a specific quote, not as a promise about a specific bill.

In practice, a CCS household ends up managing two utility relationships instead of one. SP Utilities still covers ordinary electricity, water, and gas, activated before key collection like any other flat. The chilled-water usage sits on top of that, billed through the CCS operator at the quarterly rate, tracked through the same app used to monitor usage. Budgeting for a CCS flat means checking both lines, not assuming the SP bill tells the whole story. A household that only checks the SP line each month is looking at a smaller number than the flat is actually costing to run.

The absence of an outdoor unit leads some CCS residents to assume centralised cooling needs no upkeep at all. That assumption doesn't hold. An FCU still has a coil, a fan, a filter, and a drain line, the same components that collect dust and grow mould inside an ordinary indoor unit. They foul up on the same timeline, regardless of what feeds the coil. Treating the FCU as a maintenance-free appliance is the single most common assumption this section is written to correct.

MyTengah Care+, the programme bundled with a centralised cooling sign-up, covers this directly for the first three years. That covers a workmanship warranty and FCU servicing for the full three years, plus health checks on the FCU itself, and on the piping and trunking that carry chilled water to it. That bundle is the reason most new CCS households never think about servicing in their first three years. The checks are already scheduled and already paid for as part of the sign-up.

Once the three-year Care+ period ends, FCU servicing becomes the homeowner's own arrangement, the same way it already is for every split-unit flat in Singapore. Nothing about the chilled-water side of the system changes; the shared chiller and piping stay under the CCS operator's care regardless of the Care+ status of any one flat. What ends is the free health check on the FCU, filter, and drain inside a specific unit. For a household approaching that three-year mark, this is a good time to get the FCU checked, before the free health checks stop rather than after. Booking that check costs nothing more than the time it takes, and it catches exactly the kind of slow coil fouling a Care+ health check is designed to find.

A CCS household that calls a servicer for the first time after Care+ ends is often surprised by how the conversation differs from a split-unit job. There's no condenser to inspect, no outdoor fan motor, no refrigerant level to check, so a servicer quoting for compressor work or a gas top-up on an FCU-only unit is quoting for hardware that flat doesn't have. The FCU side of the job is narrower: coil, fan, filter, and drain, and the piping that feeds the coil is the CCS operator's responsibility, not the homeowner's. A quote that doesn't match that narrower scope is worth questioning before it's accepted. The safest first question for any servicer quoting on a CCS flat is whether they are pricing the FCU alone, or pricing it as if it were a full split system.

Confirming which system a specific flat runs is a five-minute check, not a guess. The district-specific sign-up portal referenced during the BTO or resale process will confirm whether a block is on the centralised cooling list. A flat that never went through that sign-up is very likely running a standard split system, condenser included. That check is worth doing before assuming either way, because the two setups need completely different troubleshooting from day one.

A Tengah flat outside the CCS footprint works exactly like a flat anywhere else in Singapore. Regular servicing, chemical washes, gas top-ups, and compressor repairs all apply the normal way, because the outdoor unit and refrigerant loop are physically present to service. None of the centralised cooling detail above changes anything about how that flat should be maintained.

For flats on centralised cooling, the honest cutoff to plan around is the three-year Care+ mark, not any sign of trouble beforehand. A quiet FCU with no leaks and no odd noise can still be carrying three years of unfiltered dust in the coil. That build-up stays invisible until the free checks stop. A homeowner is then the one looking at it for the first time, without a scheduled check already booked.

The ledge habit from the start of this guide is still worth keeping, just pointed at a different question. Instead of checking for a condenser bracket, a Tengah resident has three things worth checking. The first is which district the block sits in. The second is whether Care+ is still active. The third is which of the two utility lines, SP or the CCS operator, actually covers a given problem. That single habit answers most of what makes a Tengah flat different from any other HDB flat in Singapore. Everything else, from how a fault sounds to how a repair gets scoped, follows from that one distinction.