Architects are in general wary of window air conditioners. Their preference is always for split ACs. According to them window ACs mar the beauty of the windows, block natural light and protrude too much behind the walls. Even if you have some window ACs with you, they will suggest you to exchange them for split ACs for your new house.

Leaving aside the window ACs, which can only be provided in an external wall of a room, either in the window or by creating an opening in the wall, a house owner has the option of going in for a split AC in each room, multi-ACs or central air conditioning with VRF system in his house. For individual houses, central air conditioning with VRF system doesn't look practicable and is quite costly also. Multi AC system, where two to four split AC indoor units are connected to one outdoor unit has been brought to the market by some AC manufacturers, but it has not succeeded much. The AC sellers themselves narrate its shortcomings. There is not much cost saving in buying it and there are power consumption concerns in case all the units are not being used regularly. The choice, therefore, gets limited to a separate split AC unit for each room.

Air conditioning provision

During the construction of new houses, provision is made these days to provide air conditioning in all rooms irrespective of whether the owner installs an AC in a room at the time of construction or at a later stage or never. As and when he desires to air condition a room, the wiring and drainage provision is available and no time is lost in installing and commissioning of the AC. PVC pipes of 2 inch diameter are provided in the walls by planning the location of split ACs. These pipes are supposed to carry the copper piping along with electric wires connecting the indoor and outdoor units of a split AC. Drain pipes are also concealed in the walls separately and are led to suitable drainage points. The benefit of making these provisions is that no wires or pipes are visible on walls when the AC indoor units are installed.

Working of split ACs
Split ACs have one indoor unit hung on the wall in a room and one outdoor unit, located outside the house (on the roof or on a bracket fixed on the external face of a wall). Two copper tubes, called refrigerant pipes connect the two units. These pipes carry the refrigerant. One pipe takes the refrigerant from outdoor unit to indoor unit for creating the cooling effect and the other pipe brings back the refrigerant to the compressor in outdoor unit for its compression and recirculation. Both the tubes are well covered with insulation. In addition, a PVC pipe connected to the indoor unit and concealed in the wall acts as drain pipe and takes away the water from AC unit to the discharge point.

Copper piping
The copper piping provided for split ACs is a costly item. Its cost varies from Rs 140 to Rs 200 per foot. The rate is for the pair of copper pipes. Copper piping should be got from the company supplies the AC units to you. It is important to check that the copper piping has been provided with good insulation. Some traders sell bad quality piping under the garb of imported copper piping. These days many Chinese copper items are available in India and these are as good as iron. One should approach a trusted dealer for getting the copper piping. The benefit of getting the copper piping done from the AC supplier is that some length, about 10 to 12 feet, is given by the supplier free of cost to the AC buyer besides free installation. Thus a good saving can be made by the house builder.

When to provide copper piping
When the AC outdoor unit is located on the roof and vertical wall from the ground to the roof is available, the conduits concealed in the walls to contain copper piping may run vertically without any bend in them. In such cases, there is no need to provide copper piping in the conduits before plastering of walls is taken in hand. However, in certain cases, the concealed conduits need to have bends. In such cases, the copper piping should be provided before taking up the plaster work in hand. The electrical and earthing wires should also be provided along with copper piping. The wires and piping should be extended by 2 ft at each end of the concealed conduit for connection to AC units later on.

Split ACs
Till a few years back, split air conditioners having star ratings from 1 to 5 were available in the market. More number of stars meant more power efficiency of an AC and more cost also. One could choose a split ACs as per one's pocket. These days, split ACs with inverter technology have stormed the market. Every AC producing company has come out with many models of inverter ACs. These ACs are termed as highly power efficient with energy saving to the tune of 60 per cent in comparison to the normal split ACs. However, cost of these ACs is very high. If a normal split AC of 1.5 tonne with 5-star rating costs Rs 35000, an inverter AC of 1.5 tonne costs around Rs 55000.

Inverter technology
While the normally prevalent split ACs are provided with star rating of 1 to 5 by BEE, no star ratings have been prescribed by BEE for inverter ACs. These ACs don't have the normal induction motor in them. In inverter ACs, once the desired temperature is achieved, the inverter units in the AC keep varying the compressor speed to maintain the temperature instead of turning it off or on frequently. Thus the power that gets consumed in normal AC in turning the compressor on again and again is saved. BEE has not considered this technology for star ratings so far.

Rating repertoire
Star ratings for ACs have become more stringent in 2012. As per the guidelines prescribed by BEE, an AC with 5-star rating but manufactured in 2011 or earlier, has become 4-star rated in 2012. Thus while buying an AC, look out not only for the number of stars but the year of manufacture also. The year of manufacture must be 2012 only. If you are buying an AC manufactured in 2011 or 2010, consider its star rating as one less than that shown on the sticker pasted on the AC. In 2015, all ACs will again undergo another star rating revision. ACs manufactured between 2012 and 2014 and having 5-star rating will become 4-star in 2015. One company has already overcome this by increasing the power efficiency of its ACs to such an extent that the star ratings of its ACs will remain unchanged even in 2015.
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  • I have a 10 X 10 room where I plan to install Split A/C (1 Ton) - (Mumbai). I have a few queries regarding the installation if somebody could help me on this

    1. This A/c will be installed in the second room of the 2 BHK , and would be sparingly used may be max 30 -45 days a year when parents or in-laws come to stay with us. Does it make sense to get a 5 star rating A/C or a 2/3 star should suffice from energy cost saving point of view. The cost differential for 5 star and 2-3 star rating AC is almost 10K

  • The cost differential for 5 star and 2-3 star rating AC is almost 10K

    It always pays to have an energy efficient AC even if cost differential is high.
    Electricity charges are going to increase(unless AAP government comes in) and even 30-45 days of use would give you saving by reduced electricity bills over two/three years.