Fitting aircon to twelve units is not twelve call-outs. Here is how a multi-unit aircon project is surveyed, priced, phased through an occupied building and handed over.
Indicative Klang Valley figures on this page are quoted from our existing cost guides and attributed where they appear. Multi-unit preliminaries — access equipment, hoisting, supervision, protection — vary too much between buildings for a published range, so they are described as drivers and quotation lines instead. WhatsApp us with your unit count for a scoped quote.
A multi-unit aircon project is any job where the same installation is repeated across many units in one programme: a block of apartments, a row of rooms, a floor of a building, a portfolio of rental units. It behaves differently from a single installation in three ways that matter to the person paying for it.
First, the repeated work becomes predictable and the one-off work becomes the risk. The tenth unit is faster than the first; the scaffold, the hoist and the building’s permit process cost the same whether you do ten units or thirty. Second, access dominates. In a single home the installer parks and walks in. In a block, someone has to book a lift, protect a lobby, get onto a ledge and get materials up. Third, the buyer is usually not the occupant — a landlord, a management body, a project owner — which makes coordination, notice and handover documentation part of the scope rather than an afterthought.
Everything below follows from those three facts. The unit selection question is separate and comes first: see aircon types and inverter vs non-inverter, because on a large order the running-cost difference is multiplied by the unit count.
What these buyers share is that a failed unit is not just discomfort — it is a vacant unit, a complaint, or a missed handover date. That is why the commissioning and defects sections below are worth more attention than the rate.
A multi-unit quotation given without a survey is a guess, and the variance shows up later as variation orders. Insist that the contractor walks the units first, and that the survey records the following per unit:
| What to record, per unit | Why it changes the price |
|---|---|
| Indoor position and whether it is a back-to-back fit | A back-to-back run is the cheapest install there is; anything else adds pipe, casing and labour |
| Pipe run length, in feet, and the number of bends | Extra copper is charged by the foot and bends slow the run |
| Where the condenser will sit and how it is reached | Ledge, roof, ground slab or bracket — this is the single biggest variable between units |
| Existing power supply at the unit | An aircon is a heavy load; an existing point may not be on a suitable circuit |
| Condensate drain route and its fall | No gravity route means a pump, a longer run, or a different indoor position |
| Whether an old unit is being removed | Removal, refrigerant handling, disposal and making good are separate work |
| Occupancy status and access window | An occupied unit is booked, escorted, protected and slower than a vacant one |
| Wall construction at the penetration | Brick, block, concrete or dry partition change coring time and making good |
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💬 Get Your Instant QuoteTwo of these are worth arguing about before signing. If the survey did not open the distribution board, the electrical scope is assumed rather than known — see DB board upgrades and adding points. And if the survey recorded pipe runs as “standard” rather than in feet, the per-foot copper line is unbounded.
A good multi-unit quotation separates the repeating work from the one-off work. That separation is what lets you add or remove units later without renegotiating the whole job, and it is what tells you who is carrying which risk:
| Line item | Unit of measure | Who should carry the risk |
|---|---|---|
| Install labour per unit | Per unit, at a fixed rate | Contractor — it is repeated work they control |
| Extra copper and drain beyond the included length | Per foot, above a stated inclusion | Shared — measured from the survey, remeasured on completion |
| The units themselves | Per unit, by brand and HP | Owner, if supplying; contractor, if supply-and-install |
| Electrical work (points, circuits, board changes) | Per point / per circuit, itemised | Owner — it is existing-condition risk, but must be surveyed not assumed |
| Access equipment, hoisting, scaffolding | Preliminaries — a lump sum for the job | Contractor, once the building is surveyed |
| Protection, cleaning and waste removal | Preliminaries | Contractor |
| Supervision and programme management | Preliminaries | Contractor |
| Removal and disposal of old units | Per unit removed | Contractor, priced explicitly |
| Commissioning records and handover pack | Preliminaries | Contractor — and it must be a named deliverable |
The batching benefit is real but it belongs to the preliminaries, not to the per-unit rate: the survey, the access equipment and the supervision are spread across the unit count. Our aircon servicing cost guide shows the same effect on the maintenance side, where doing three or more units in one visit typically saves RM20–RM40 per unit against calling someone out separately. Expect a contractor to reflect that logic; be suspicious of one who discounts the per-unit labour steeply instead, because the labour at each unit does not get cheaper with volume.
Every multi-unit number starts from a single installation, so it is worth anchoring on the published figures for one. Our aircon installation cost guide puts a standard wall-mounted back-to-back installation in the Klang Valley at RM300–RM700 in labour, plus roughly RM30–RM60 per foot for copper piping beyond the short included length, with the unit itself at RM1,200–RM4,500+ depending on brand and HP.
Multiply that out and you have an order of magnitude, not a quotation. What the multiplication misses, and what the survey exists to catch, is the tail: the three units on the shaded side that need a longer run, the two whose condensers cannot sit where the others do, the one whose drain has no gravity route. On a well-surveyed job that tail is priced. On a badly surveyed one it arrives as variations after the contractor is already on site and you have no leverage left.
Note also which side of the supply line you are on. Owner-supplied units give you buying power and take the equipment warranty conversation onto your own desk; contractor-supplied units give you one party responsible when a unit fails in month three. Neither is wrong, but decide it before tender, because it changes every rate in the document.
Access is where multi-unit projects go over budget, and it is almost entirely knowable in advance. The questions to settle at survey are physical and specific:
Coring through an external wall deserves its own conversation, because it is the step most likely to create a problem someone else will pay for later. A sleeve with the wrong fall, or a penetration left unsealed, is how water gets into a wall — the failure mode set out in our aircon wall penetration leak guide. Multiply that by thirty units and it is a defects programme.
A vacant block is a straightforward programme: sequence by floor and work through. An occupied one is a scheduling problem where the constraint is other people’s consent, and it is worth building the programme around that rather than fighting it.
What works, in practice: agree a notice period with the occupants and hold to it, because a missed appointment costs a whole unit-day. Group units by stack rather than by floor where the pipe routes share a shaft, so scaffolding and hoisting are set up once. Keep a no-access list from day one and price a second visit for it explicitly, because there will be one. Book the noisiest step — coring — into the building’s permitted window and do all of it in as few sessions as possible. And leave every unit habitable at the end of each day, even mid-installation, because an occupant who loses a night’s sleep withdraws access from the whole programme.
Handover of each unit should be individual and immediate, not saved to the end. A signed-off unit is a unit you stop carrying risk on.
In most Klang Valley strata buildings the management office controls whether this work can happen at all, and their requirements are usually procedural rather than technical. Expect to submit the contractor’s details and workers’ identification, place a refundable renovation or works deposit, provide insurance details, and accept the building’s working hours and access rules. Where the units serve common property rather than private lots, the approval route goes through the management body itself and typically involves a committee decision and a tender — a process familiar from any common-area works programme, such as the one described in our JMB common-area waterproofing guide.
Two things are worth confirming in writing before mobilisation. First, who reclaims the deposit and on what condition, since it is usually released against a joint inspection of common areas. Second, what the building requires of the contractor’s registration and insurance — larger jobs and management-body tenders frequently ask for contractor registration, which our CIDB contractor guide explains, and the risks of engaging an unregistered one are set out in what happens if your contractor is not CIDB registered. Confirm the current requirements with the building and with the relevant authority rather than relying on any summary, including this one.
On a single installation, commissioning is the installer switching the unit on before leaving. On a multi-unit project it is the deliverable that protects you, because you cannot personally stand in thirty rooms. Ask for it as a named line in the contract:
| At handover you should receive | Why it matters later |
|---|---|
| A unit schedule: location, brand, model, HP, serial number | Without serials you cannot claim an equipment warranty on a specific unit |
| Commissioning record per unit | Proves each unit was run and checked, not just hung |
| Drain test evidence per unit | Drain faults are the most common early failure and the most disputed |
| Photographs of each pipe run before it was covered | The only record of what is behind the casing or the plaster |
| Electrical work record | Which circuit each unit is on, and what was changed at the board |
| Warranty documents, equipment and workmanship stated separately | They have different durations and different claimants |
| A named defects period and a response time | A warranty with no response time is a warranty you chase |
Ongoing maintenance is a separate purchase and should be tendered as one, not folded into the install price where it is invisible. It is bought as a scheduled preventive-maintenance agreement with its own scope and service levels — our aircon maintenance contract guide covers how those are scoped and priced, and puts per-visit servicing of a commercial split or cassette at RM80–RM150 a unit. Decide the maintenance route before handover, so the first service happens on schedule rather than after the first complaint. What that servicing involves is covered in our chemical service guide.
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