Air Conditioner - EER, Star rating, Selection.

Discussion in 'Home Appliances and Gadgets' started by nevinjohn, Mar 30, 2012.

  1. nevinjohn

    nevinjohn Active Member

    Air conditioning is no longer a luxury, but has become a necessity to Indians. Planning to buy an air conditioner? Well, there are some things which can help you out in determining the right product.

    This machine is a power hungry device, and buying an inexpensive model will make you shed more on the power bills. As a rule of thumb, one can expect 990W/TR. Means, a good model (star rated) would approximately consume 990W /hour for a 1TR model split A/c. Consider Rs.3/kWh* (BSES Delhi).
    This means, 0.99KW X 3Rs X 10 hours/day = 29.7 Rs/day x 30 days = Rs 891/month.

    Consider running the unit for 10 hours. It has to be noted that the air conditioner doest consume full power all the time, but only when the compressor runs. Buying an under sized air conditioner makes the compressor running 24 X 7, causing huge power bills, in efficient cooling and quick wear and tear to the compressor. So, choose the right capacity . Models are available ranging from 0.8TR to 3.0TR Split units.
    So, if the right capacity is selected, the compressor runs 8 hrs(approx), and save 162 Rs/month. (Do the math). So how to determine the right capacity?

    As a rule of thumb, consider 1 TR for 120sq.ft bed room.Again, keep in mind if any of the walls of the room is having a West exposure, consider the next higher capacity, as sun gain is high in this side. (The dealer will help you in this, else go to the website of any brand, and you have the option to determine this).

    Now that you know what capacity is needed, the next thing which you need to know is the technology. The heart of any air conditioner is the compressor, and this is where the technology is. For a typical airconditioner, once the desired temp is reached, the compressor stops, while the blower is still on. As the temp of room rises, the compressor kick starts. The power drawn can be seen if the lights of the room are on, and there’s this slight dimming of lights for a fraction of second. This process repeats, and compressor comes On and Off as required at a constant speed.

    Inverter technogy / DC Inverter

    This is the latest technology, where in the air conditioner has a variable speed compressor. The term “DC Inverter” is because ac current is converted into dc, and the frequency is varied, according to the speed required. (Typical ac power is at 50Hz, 230V). Unlike the traditional method, the compressor regulates the speed according to the load, and there’s no frequent On and Off of compressor cycle saving energy, and wear and tear of the machine. As a matter of fact, a 1 TR machine will work for 300-400W/TR for minimum. So, see the savings for yourself. Technology comes for a price, and so these units are priced accordingly. Also, the temp remains constant in the room, as the compressor varies its speed as required.

    BEE/Star rating

    Cooling capacity is defined in TR.
    1 TR = 12000 BTU/hr
    1 TR = 3512 W (This is not the power consumption, but cooling capacity in Watts)
    1 TR = 3024 calories/hour

    Even though unit expressed in TR is common, different companies express capacities in different units as mentioned above. To find the star rating, covert the capacity in terms of Watts (cooling capacity)

    For a 1TR machine, this is 3512 Watts. (Cooling capacity). Now determine the power consumption. Check the unit, (outdoor unit) on which this is written. Consider 990W.

    Divide cooling capacity by power consumtion, this gives the EER (Energy Efficieny Ratio)

    In our case, 3152 / 990 = 3.5
    Star rating is determined from this value. 3.5 is 5 star rating.
    More can be found on the website of Energy Efficiency.

    Best Quality Brands suggested are:-
    1. Carrier
    2. Daikin
    3. Blue Star
    4. Voltas

    *Electrical rates changes according to slab/usage.

    Parminder and Preeti_20 like this.
  2. sahilsolanki

    sahilsolanki New Member

    If you are looking for Air Conditioner then I suggest you to choose Voltas,Recently I purchase a Voltas Split AC of 1.5 ton
    Last edited by a moderator: May 17, 2013
  3. jhone89

    jhone89 New Member

    Voltas is not best i have used it last year VOltas perform for year, now i am using Geranal Air Conditioner.
    if you want to save your money and make Air Conditioner your asset buy only Geranal Air Conditioner.
  4. Admin

    Admin Administrator Staff Member

    Very informative thread. Thanks for posting. I dont know how I missed it last year as I just landed here following a link you posted in another thread. I wonder what your thoughts are about the airconditioners with inverter technology.
  5. nevinjohn

    nevinjohn Active Member

    Thank you. May be just4kix can consider having this link in his "list of useful links".

    As for what you asked, you may have a look at this page. Also look at the specifications tab. There's no doubt that power savings are huge, but the capital cost is also huge.
    Hitachi - Revolutionary Clean SX/SD Series?
  6. Rishiguru

    Rishiguru New Member

    Very informative post. Thanks.

    I just did not understand the part of the quote above. By mentioning the above four brands as "Best Quality Brands" did you mean:

    The companies with highest technical expertise in their field


    Provides quality components in their products


    Have best after sales service.
  7. nevinjohn

    nevinjohn Active Member

    all the three...
  8. Admin

    Admin Administrator Staff Member

    @ nevinjohn

    Do you know if any company makes window type airconditioners with DC inverter technology? I have looked at all major manufacturers but none of them seem to have it in window units. Its all split ones. I am going to buy a window AC in a day or two so was wondering which one to buy but has to be a window unit.
  9. nevinjohn

    nevinjohn Active Member

    Unfortunately, No... I'd still suggest that you go with the 5 star rating.
  10. Admin

    Admin Administrator Staff Member

    I got a second hand Toshiba for Rs4000 and that included fitting and I had a spare stabilizer at home. I wanted to buy a Hitachi 1.5ton and that was for Rs36000 so it is a neat saving of Rs 32000+ if you consider the cartage and fitting charges. This 4k AC is doing a great job and it is a 2tonner so it chills the room better then anything I have seen before and the gentleman who sold it got it from Kenya some 20 years ago and it has never broken down as per the guy who arranged it for me. First thing is the noise which is virtually nonexistent. I got it fitted in the wall instead of a window as the guys suggested sir ji awaz kam karega wall mein :) Aur zada din chalega :)

    Why I got this one?

    Its a south facing fifth floor room with naked walls to the east and west and also happens to be the top floor so the roof gets pretty hot as well and previously I had an old Onida here which had to keep the compressor running all the time if the room was to feel comfortable atall thanks to the "hot" walls.

    If I would have got the 36K Hitachi with all 5 stars and what not I would have never recovered the costs if you compare it with what I have paid now :) The only risk being if this old fart decides to break down one day. If this AC keeps working even for this season I am still in profit. As long as I am saving/making money I dont give a toss about the stars :) Do you? Stars and all are about saving electricity and that translates into saving money.

    I might do something to insulate these walls one day if I can think of something that wont make the room look ugly from inside atleast.

    If they had any window units with inverter comprosser I wouldnt mind paying a lot more money purely because it would keep the room at a more constant temperature.
    nevinjohn likes this.
  11. nevinjohn

    nevinjohn Active Member

    A second hand window airconditioner with no repairs means the internals are still intact, and theres virtually no refrigerent leak so far....
  12. Preeti_20

    Preeti_20 Active Member

    Is there any type or kind of air conditioner which doesnt use a lot of electricity?
  13. nevinjohn

    nevinjohn Active Member

    For residential purposes, unfortunatly no. Although you might find some fridges which uses Peltier Effect. These are marketed as electric coolers. These fridges doesnt have any compressor which is the main power consuming device.
  14. Yogi

    Yogi New Member

    Damn! Air conditioners have become such a need these days that each room in the house needs to have an AC.

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