AC Types: Split, Cassette, Ductless and VRV

Air-conditioning has moved from a luxury to an expectation in Indian homes, especially in the hot, humid cities of the west coast and the dry heat of the north and centre. Yet the choice of system is still usually made in a showroom, a few weeks before moving in, long after the false ceiling, the furniture and the electrical layout are fixed. The result is familiar: an outdoor unit hung where it cannot breathe, a pipe run that crosses a freshly painted wall, a 1-ton unit fighting a west-facing glass wall, or a cassette ordered for a room that has no ceiling space left to hide it.

The vocabulary adds to the confusion. Brochures speak of split, hi-wall, cassette, ductless, ductable, ducted, multi-split, VRV and VRF, and the same word can mean different things from different sellers. In fact the systems fall into a few clear families, each with its own space needs, installation rules, costs and limits. Once those are understood, the right choice for a 2BHK flat, a 5,000 sq ft villa or a 3,000 sq ft office becomes fairly obvious.

This guide explains each family, how to size it in tons, the space it needs in walls and ceilings, the clearances that keep it efficient, what the BEE star label means, and what each costs as an indicative October 2026 range. It is written for homeowners and business owners coordinating air-conditioning with their interiors — the design decisions that should be made before the false ceiling goes up, not after. Detailed load calculations, refrigerant piping design and electrical design should always be done by a qualified HVAC contractor or consultant.

A short history of cooling indoors

Indian buildings were cooled for centuries without machines: thick walls and courtyards, jaalis and jharokhas, stepwells, khus screens wetted to cool the breeze, and the hand-pulled punkah of colonial bungalows. Mechanical air-conditioning began in the United States in 1902, when Willis Carrier designed a system to control humidity in a printing works; it was an industrial process tool long before it was a comfort appliance. For most of the twentieth century air-conditioning in India meant central plants in cinemas, hotels and offices, and window units in the homes of a few.

The split AC changed that. By separating the noisy compressor and condenser into an outdoor unit and leaving only a quiet fan coil inside, it made room air-conditioning practical in flats. Variable refrigerant flow systems — introduced by Daikin in Japan in 1982 under the name VRV, and now made by many manufacturers under the generic name VRF — extended the idea to whole buildings, with one outdoor unit serving many indoor units. Over the last fifteen years inverter compressors, which vary their speed instead of switching on and off, have become the norm in Indian homes, encouraged by the Bureau of Energy Efficiency's star labelling. The India Cooling Action Plan, published by the Government of India in 2019, set the national direction: more efficient equipment, better building design to reduce cooling demand, and a shift to refrigerants with lower climate impact.

The AC families explained

Every air-conditioner moves heat from inside to outside using a refrigerant that is compressed, condensed, expanded and evaporated in a loop. What distinguishes the families is where the parts sit and how the cooled air reaches the room. The key distinction is between ductless systems, which blow air directly into the room from a unit in the wall or ceiling, and ducted systems, which hide the unit and carry air through ducts to grilles or diffusers.

Wall-mounted split (hi-wall)

The familiar split AC: an indoor fan-coil unit on the wall, connected by two insulated copper pipes, a drain pipe and a cable to an outdoor condensing unit. It is ductless. Capacities run from about 0.75 to 2.5 tons. It is the cheapest system per room, quick to install, easy to service and independent in each room, which is why it dominates Indian homes. Its weaknesses are visual — a white box on the wall and an outdoor unit for every room — and the limit on how far the outdoor unit can be from the indoor unit.

Cassette

A cassette is also ductless, but its indoor unit sits in the false ceiling with only a square grille visible, blowing air in one, two or four directions. Compact four-way cassettes fit a 600 × 600 mm ceiling grid and are typically up to about 2 tons; full-size units with panels of roughly 950 × 950 mm go to 3–4 tons or more. Cassettes spread air evenly across large, open rooms — living–dining areas, showrooms, clinics, offices — and are less visible than a wall split. They need a ceiling void, a drain pump, and careful coordination with lights and ceiling design.

Ducted or ductable split

A ducted unit hides the indoor fan coil above the false ceiling, often over a corridor or toilet, and delivers air through insulated ducts to linear slot diffusers or grilles, with a return path back to the unit. Only the grilles are visible. One ducted unit of 2–5.5 tons can serve a large living room or several connected spaces. It is the quietest-looking option and suits premium homes, restaurants and offices, but it needs the most ceiling space, a dedicated design, access panels for maintenance, and a single thermostat serves every room on that unit unless zoning dampers are added.

Multi-split

One outdoor unit connected to two to five indoor units — wall, cassette or ducted — in different rooms. It reduces the number of outdoor units on the facade, which helps where the society restricts them, but if the outdoor unit fails, every connected room loses cooling, and the combinations of indoor capacity are limited by the manufacturer's rules.

VRV / VRF

Variable refrigerant flow is the large-scale version of the idea: one outdoor unit, or a bank of modules, connected by a branched refrigerant network to many indoor units of any type — wall, cassette, ducted, floor-standing — each with its own control. The compressor and electronic valves vary the refrigerant supplied to each indoor unit to match its load. VRV is Daikin's trademark; VRF is the generic name used by other manufacturers. VRF suits villas, large apartments, offices, clinics and hotels, where many rooms need independent control and the facade must stay clean. It costs more, needs specialist design and installation, and is a long-term commitment to one manufacturer's system.

What "ductless" means

Ductless is not a separate product; it is a category. Any system in which the indoor unit delivers air directly into the room — wall splits, cassettes, floor-standing and ceiling-suspended units, and the indoor units of most multi-split and VRF systems — is ductless. The term is common in international literature as "ductless mini-split". In India, "ductable" or "ducted" is its opposite. A VRF system can be ductless, ducted or a mixture of both.

Sizing: how many tons does a room need?

A ton of refrigeration (TR) is a rate of cooling: 12,000 BTU per hour, or about 3.5 kW of heat removed. The correct size depends on far more than floor area — orientation, glass, roof exposure, occupancy, lighting, appliances, the ceiling height and the climate all matter, and a proper heat-load calculation by the HVAC contractor is the right basis for any large or unusual space. For ordinary Indian rooms with a 2.9–3.0 m slab height, normal walls and modest glazing, the rule-of-thumb bands below are widely used as a first check.

Both undersizing and oversizing cause problems. An undersized AC runs flat out and never reaches the set temperature on hot afternoons. An oversized one — the more common mistake — cools the air quickly and switches back or slows down before it has removed enough moisture, so the room feels cold and clammy, which is especially noticeable in humid cities such as Surat and Mumbai. Inverter units handle a modest oversize better than fixed-speed units because they throttle down, but sizing still matters. The cheapest capacity is the one never needed: shading west windows, insulating the roof of a top-floor flat, using light-coloured roof finishes and sealing gaps around windows reduce the load, as explained in the passive cooling guide on this site.

Installing a wall split correctly

Most of the complaints about split ACs — water dripping on the wall, poor cooling, noise, high bills, early compressor failure — trace back to installation rather than the machine. The elevation below shows the clearances commonly required. Exact figures differ between manufacturers, and the installation manual of the unit being fitted always takes precedence.

Indoor unit

The indoor unit is usually mounted with its underside at about 2100–2400 mm, with the clearance above it that the manual specifies — commonly around 150 mm — so the return air can enter freely. It should blow along the length of the room, not straight at the bed head or the sofa, and not into a curtain or a beam that will deflect the air back. In bedrooms the best position is usually on the wall opposite or beside the foot of the bed, or on a side wall throwing air across the room. The pipe hole should be planned before the wall finish and furniture: a hole of about 65–75 mm, sloping slightly down to the outside, sleeved, and located so the pipes do not run exposed across the wall.

Outdoor unit

The outdoor unit rejects all the heat taken out of the room, plus the compressor's own heat. If it cannot breathe, efficiency drops and the compressor works harder. It needs open air in front — commonly 500 mm or more — and clearance behind and at the sides, and it should not face another unit's exhaust. Many Indian buildings place outdoor units in narrow ducts or behind dense louvres for appearance; this often causes hot air to recirculate. If a screen is needed, it should be a widely spaced louvre or perforated panel with a high open area, set well away from the fan. Shade helps, but a roof over the unit should not trap air. Units on ledges and brackets must be accessible for servicing and safely fixed — a falling outdoor unit is a serious hazard on a high-rise facade.

Pipes, drain and power

The refrigerant lines should be of the specified diameter and wall thickness, fully insulated, as short and direct as possible, and pressure-tested and vacuumed before the refrigerant is released. Each split has a maximum pipe length and height difference; long runs need extra refrigerant and reduce capacity. The condensate drain should fall continuously at about 1:100 to a gully, a floor trap or a dedicated drain stack, never onto the facade or a neighbour's balcony. Electrically, each AC should have its own circuit and MCB sized for the unit, with proper earthing; larger units are often hard-wired through an isolator. Most modern inverter units tolerate a wide voltage range, so a separate stabiliser is needed only where the supply fluctuates badly — the manufacturer's guidance should decide.

Cassette and ducted units: the ceiling decides

Cassette and ducted systems must be designed with the false ceiling, not inserted into it later. They need depth above the ceiling, a drain route, hangers to the slab, access for maintenance and positions that do not clash with beams, lights, sprinklers or curtain pelmets. The section below compares the space each needs.

A cassette typically needs a clear void of roughly 250–350 mm, depending on the model, plus room for the drain pipe to fall from the pump outlet. The built-in drain pump can lift condensate a limited height before it must fall — the figure varies by model — which allows the drain to cross over beams. The grille fits a standard ceiling module, and it reads best when the ceiling layout is planned around it: centred in the room or in a coffer, aligned with downlights, away from pendants and curtains. Ducted units need more: often 350–450 mm over the unit and the main duct, plus a return-air path from every room served. They are commonly placed over a corridor, a toilet or a wardrobe passage where the ceiling can be lower, with linear slot diffusers along the edge of the main rooms.

In a typical Indian apartment with a floor-to-floor height of about 3.0 m and beams of 450–600 mm, the false ceiling is often only 2.6–2.7 m high. That leaves enough room for compact cassettes between beams but often not for ducted systems across the whole flat, which is why ducted units in apartments are usually limited to a large living–dining space with the unit placed over an adjacent passage. The ceiling height guide on this site gives the room-by-room minimums to respect.

VRV / VRF in a villa or office

In a VRF system, one outdoor unit — or a group of modules on the roof or in a service yard — feeds a branched refrigerant network. Special joints called branch kits or refnets split the pipes to each indoor unit, and each indoor unit has an electronic valve that adjusts its share of refrigerant. Because not every room needs full cooling at the same moment, the connected indoor capacity can usually exceed the outdoor capacity within limits set by the manufacturer. Heat-recovery versions can even cool some rooms while heating others, which is rarely needed in most of India but useful in hill stations and cold northern winters.

VRF's advantages are real: one outdoor location instead of a facade full of units, much longer pipe runs and larger height differences than splits allow, individual control in every room, efficient part-load operation, and central controls that can show energy use per area — useful in offices. Its disadvantages are equally real: a much higher first cost, dependence on a specialist installer and one manufacturer's spares, a single outdoor unit that, if it fails, affects the whole system (larger installations reduce this with multiple modules), and the need for a clear refrigerant shaft and a roof or yard position from the start of design. In occupied buildings with many people, the fresh-air requirement must also be addressed separately, because VRF units recirculate room air.

Energy labels, ISEER and refrigerants

Room air-conditioners sold in India carry a Bureau of Energy Efficiency star label. For inverter units the rating is based on the Indian Seasonal Energy Efficiency Ratio (ISEER), which estimates efficiency over a typical Indian year at a range of outdoor temperatures rather than at one test point. A higher ISEER means less electricity for the same cooling. The star thresholds are revised periodically, so a 5-star unit from several years ago may equal only a 3- or 4-star unit today; the label shows the year of validity and the rated annual energy consumption, which is the most useful single figure for comparing models. BEE guidance has also made 24 °C the default temperature setting on new room ACs, because every degree lower adds noticeably to energy use.

Refrigerants are changing too. Older units used R22, which damages the ozone layer and is being phased out under the Montreal Protocol. Most current Indian splits use R32 or R410A, and some manufacturers offer R290 (propane), which has a very low global-warming potential but is flammable and therefore needs trained installers. India has ratified the Kigali Amendment to the Montreal Protocol, which commits it to a gradual phase-down of high-impact HFC refrigerants over the coming decades. For a homeowner the practical points are to choose a current-generation refrigerant, to insist on vacuuming and leak testing during installation, and never to accept "gas top-ups" as routine maintenance — a correctly installed system should not lose refrigerant.

What each system costs

The figures below are indicative October 2026 ranges for branded equipment in Indian metros and tier-2 cities, for supply and standard installation. They exclude the false ceiling, civil work, painting, electrical cabling beyond the AC point and GST unless noted, and they vary with brand, star rating, features and the length of pipe runs. A written quotation against a drawing should always be obtained.

Which system for which project

For most flats up to about 3BHK, inverter wall splits remain the sensible default: lowest cost, independent rooms, simple service and no ceiling penalty. A compact cassette in the living–dining room is a good upgrade where the ceiling allows and the wall split would be visually awkward, for example on a feature wall. Ducted units are worth considering in a large living–dining space in a premium flat, with the unit over the passage. VRF makes sense when there are many rooms, the facade or society rules limit outdoor units, a clean architectural expression matters, or central control and energy monitoring are wanted — typically villas above about 3,000 sq ft, penthouses, offices, clinics and boutique hotels. In Aaditya Interior's projects, the decision is taken at the layout stage, because the false ceiling, the electrical load, the outdoor-unit locations and the drain routes all follow from it.

Where cooling is heading

Cooling demand in India is growing fast, and with it the pressure on electricity grids at peak hours. The direction set by national policy and the industry points to four changes. Equipment will keep getting more efficient as BEE thresholds rise. Refrigerants will move towards lower-impact options under the Kigali phase-down. Buildings will be expected to need less cooling in the first place through shading, insulation and better glass, as encouraged by the Energy Conservation Building Code for commercial buildings and its residential counterpart, Eco Niwas Samhita. And cooling will increasingly be supplied at a larger scale — GIFT City in Gujarat, for example, was planned with a district cooling system serving many buildings from a central plant. For homes, the most effective future-proofing is simple: design to reduce the load, choose efficient inverter equipment, use a ceiling fan with the AC at 24–26 °C, and leave space, power and drains for the system that may replace today's in fifteen years.

Nine rules for choosing and installing an AC

• Decide the AC type at the layout stage, before the false ceiling and furniture are designed.
• Size by heat load, not by habit: about 1 TR per 100–150 sq ft for ordinary rooms, more for west glass, top floors or crowds.
• Reduce the load first — shade west windows, insulate top-floor roofs, seal gaps — and buy a smaller, efficient unit.
• Choose inverter units with a current BEE label; compare rated annual kWh, not just stars.
• Keep outdoor units in open air with at least about 500 mm in front; never inside a closed duct or dense screen.
• Give every AC its own circuit and MCB with proper earthing, and plan the drain to a gully with a continuous fall.
• For cassettes, check beam depths and allow about 250–350 mm of void; for ducted units, 350–450 mm and a return path from every room.
• Insist on pressure testing, vacuuming and full insulation of copper lines; routine gas top-ups mean a leak.
• Choose VRF only with a specialist designer and installer, and fix the outdoor location and refrigerant shaft early.

Frequently asked questions

What is the difference between split AC and VRV?

A split AC is one outdoor unit serving one indoor unit (or a few, in a multi-split). A VRV or VRF system uses one outdoor unit, or a group of modules, to serve many indoor units through a branched refrigerant network, adjusting refrigerant to each room. VRF costs more but gives one outdoor location, longer pipe runs and individual control across a whole villa or office.

Is a cassette AC better than a split AC?

For large, open rooms a cassette distributes air more evenly in four directions and is less visible. For bedrooms and small rooms a wall split is cheaper, needs no ceiling void and is easier to service. A cassette only makes sense where there is a false ceiling with about 250–350 mm of space between beams.

What does ductless AC mean?

Ductless means the indoor unit blows conditioned air directly into the room rather than through ducts. Wall splits, cassettes and floor-standing units are all ductless. The opposite is a ducted or ductable system, where the unit is hidden above the ceiling and air travels through ducts to grilles.

How many tons of AC do I need for a 12 × 14 ft room?

A 12 × 14 ft room is 168 sq ft. Under normal conditions a 1.5-ton inverter split is the usual choice; a 1-ton unit may struggle on hot afternoons, especially on a top floor or with west-facing glass. For unusual rooms — large glazing, double height, many occupants — ask for a heat-load calculation.

Is VRV worth it for a home?

It is worth considering for large homes with many rooms — typically villas, penthouses and 4BHK-plus homes — where a clean facade, one outdoor location and central control matter. For a typical 2BHK or 3BHK flat, inverter splits deliver similar comfort at roughly a third to a half of the cost.