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Old 23rd May 2011, 20:55   #1891
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by sanjayc View Post
I don't think there any straight-cur answer to that.

Depends on what final temp one wishes to attain. For me, air conditioning means comfortable temp (usually 25-26), not chilling, hence a lower tonnage should suffice. Further, even BEEE guidelines says, a slightly lesser tonnage than reqd is good in terms of power savings, so that frequent compressor on/off cycles are avoided.

There are other factors too be looked into - if the room is frequently opened or too crowded, then the ac will struggle to attain the set temp. If one is starting the ac only at 12 noon, be prepared to wait it out longer for a comfortable temp.
does that essentially mean that if a person is ok with the ac doing 25-26 then he probably can go for a 1 ton ac instead of a 1.5 ton for a 150 sq ft room with the disadvantages being..

1. longer time to cool room. i guess a 1 ton will probably 10-15 mins more than a 1.5 ton to cool to 25-26 degrees from 42 degrees.

2. the 1 ton AC not being able to go below 25 degrees in a 150 sq ft room.

If the above is true then it might make a lot of sense for people who are OK with the above 2 points to go for a 1 ton AC instead of a 1.5 ton and save money on Purchase Cost and Electricity running costs.

What Say ?

Regards,

Rana
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Old 23rd May 2011, 21:17   #1892
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Originally Posted by Mustang.101 View Post
This is because of a local naala that runs about 300 yards flying distance from my house. It is a known fact in our society that all window ACs whose rear are facing the naala develop leaks in the gas circulation system or in the compressor. It is said that this effect exists within a 1km radius of the naala.

However i have had no problems with White westinghouse and my friend has not had a problem with daikin.

I have had problems with general and the others as mentioned in my earlier post.
In which case you should tell the MCD or Shiela Dikshit about this You are wasting money on changing equipment which would have lived 10 years without a problem because of the obnoxious gases from the Nallah. Raincheck time man - what would it do to one's lungs - especially kids.

If the nallah fumes are the reason...God help !! Do bring this to the notice of the Environment Minister..

Quote:
Originally Posted by rana_kirti View Post
does that essentially mean that if a person is ok with the ac doing 25-26 then he probably can go for a 1 ton ac instead of a 1.5 ton for a 150 sq ft room with the disadvantages being..

1. longer time to cool room. i guess a 1 ton will probably 10-15 mins more than a 1.5 ton to cool to 25-26 degrees from 42 degrees.

2. the 1 ton AC not being able to go below 25 degrees in a 150 sq ft room.

If the above is true then it might make a lot of sense for people who are OK with the above 2 points to go for a 1 ton AC instead of a 1.5 ton and save money on Purchase Cost and Electricity running costs.

What Say ?

Regards,

Rana
Putting this in prespective. One ton cools a room 10x10x10 so one needs to calculate on that basis. If you put an under capacity AC your utility bills will actually rise, as the machine is trying to cool an area larger than it is designed to do. It would be better to have extra capacity unit with lower utility bills. That is just my opinion, but well thought.

Last edited by manson : 24th May 2011 at 14:56. Reason: Kindly use Edit button to merge posts whilst posting within twenty minutes from the first post.
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Old 23rd May 2011, 22:10   #1893
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Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by rana_kirti View Post
does that essentially mean that if a person is ok with the ac doing 25-26 then he probably can go for a 1 ton ac instead of a 1.5 ton for a 150 sq ft room with the disadvantages being..

1. longer time to cool room. i guess a 1 ton will probably 10-15 mins more than a 1.5 ton to cool to 25-26 degrees from 42 degrees.

2. the 1 ton AC not being able to go below 25 degrees in a 150 sq ft room.

If the above is true then it might make a lot of sense for people who are OK with the above 2 points to go for a 1 ton AC instead of a 1.5 ton and save money on Purchase Cost and Electricity running costs.

What Say ?

Regards,

Rana
I don't think 1T can replace 1.5T in most cases though a 1.2T can work out.

The BTU requirement formula I picked up from a website (which I now forget the link, but it belonged to uk energy board as far as I remember) is as follows:

Room BTU= 337 x Width x Length (in meters)
Window BTU = 165 x Width x Length (in meters, of the window)
People BTU = 400 x no. of people
Equipment BTU = 3.5 x total watt consumption of all electronics in the room

Adding all the above will give the total BTU. Play around with the above (e.g, if window is not facing the sun, and covered with heavy curtain, minimize the area etc).

It gets more complicated in case the room is on the topmost floor, outside temperature conditions etc.

If in doubt or room conditions cannot be controlled, I will say go for the optimal tonnage otherwise a lower tonnage would do.
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Old 23rd May 2011, 23:59   #1894
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Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by rana_kirti View Post
If the above is true then it might make a lot of sense for people who are OK with the above 2 points to go for a 1 ton AC instead of a 1.5 ton and save money on Purchase Cost and Electricity running costs.

There are other ways of saving power and that would start by using the correct gauge of wires, using properly rated energy efficient appliances and fixtures etc. If what is being said in posts above were correct a Tata ace would have sufficed for all kinds of loads out on the highways.

Quote:
Originally Posted by Ricky_63 View Post
Putting this in prespective. One ton cools a room 10x10x10 so one needs to calculate on that basis. If you put an under capacity AC your utility bills will actually rise, as the machine is trying to cool an area larger than it is designed to do. It would be better to have extra capacity unit with lower utility bills. That is just my opinion, but well thought.
+1

Their are various components in the air con which get effected by undue loads or extra long running of not just an underrated but even properly rated machines whose heat exchange rate is not able to keep up with the load of the ambient.

As the comp keeps on running the first thing to go will be the running capacitor once it heats up and crosses its safety thresh hold the inbuilt circuit would trip the compressor, the thermostat however will be sending signals to switch back on and as soon as the cap. has cooled just enough the comp will switch back on and the whole cycle will repeat thereby consuming more and more power, not to mention eventually leading to a burst capacitor. This on off will not even be noticed as the ac will never really cool but will be in a hung state. The starting capacitor will also suffer on account of all this repeated on off. The small sized heat exchanger will never be able to cool down the hot gas to an acceptable level and the compressor will end up working harder and longer to compress all of that hot gas which should have arrived completely cooled off, a process which only raises the pressure even higher. Soon you have gas under higher than normal pressure travelling through the system. This is the beginning of the end as repeated cycles will lead to an abnormal increase in the pressure within the system thereby tripping the high pressure switch and now your machine is really done for. The compressor will trip and go into safety mode and leave the fan running to enable heat exchange to keep on taking place so that the system cools down only to restart and repeat the cycle all over again. Of course all this tripping happens only if the high pressure in the system is not relieved by the weakest joint in the tubing etc not giving away in the first place. This of course results in what else but a gas refill which will not only introduce gas of questionable purity to be charged (leading to lifetime of inefficiency) and which will cost you atleast as much as the aircon's electricity bills for atleast one season.

Chill.

Quote:
Originally Posted by sanjayc View Post
The BTU requirement formula I picked up from a website (which I now forget the link, but it belonged to uk energy board as far as I remember) is as follows:

Room BTU= 337 x Width x Length (in meters)
Window BTU = 165 x Width x Length (in meters, of the window)
People BTU = 400 x no. of people
Equipment BTU = 3.5 x total watt consumption of all electronics in the room

Adding all the above will give the total BTU. Play around with the above (e.g, if window is not facing the sun, and covered with heavy curtain, minimize the area etc).

It gets more complicated in case the room is on the topmost floor, outside temperature conditions etc.

Those formulae will not work for our ambient conditions as the constants in there are based on the local ambient of whichever temperature zone UK falls in. I have said this before and I will say this again that we have to calculate for a summer ambient which has an average temperature of high 30 degree C and not low 20s and that too on the rare sunny days.

I did a quick calculation using the above formulae for a 20'x15' room with 2 windows of 4'x4', 4 people and other appliances in the room consuming 1000W. The result is 14900 btu/hr and that is for the UK with summer afternoon temps of 15 degree C to maybe 24C on a rare day. Even they want a 1.2 ton aircon. So it is best left to all of your imaginations how much comfort a 1 ton air con will provide when temperature here at 8 am is 31 degree C only to go up to 41 by 1 pm on almost all days from May through July.

Ciao
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Old 24th May 2011, 09:34   #1895
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Default Re: Which home/office AC (air conditioner) to buy ?

My formula is

1 ton for every 1000 cu.feet (10 x 10 x 10) or (11 x 10 x 9, as most ceilings are low now a days)
1 ton for every 4/5 persons
1 ton for every 3KW electric appliances in the room

This works perfectly in Delhi Summer Heat
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Old 24th May 2011, 10:09   #1896
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I got the Daikin 1.5 ton 3 star split ac 2 nos. Installation was done yesterday, price came to a total of 70k all inclusive. Vat in Karnataka is more compared to other places, so its naturally more expensive here.
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Old 24th May 2011, 15:05   #1897
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Default Re: Inputs needed for 1.5T AC around 25K all inclusive

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Hi Guys

I'm shopping for an 1.5T Split AC. I already have the Samsung AS182SGD 1.5T at home. No issues with the unit or service so far, so I prefer the Samsung. Now the question is which model? Price quotes from Rathna Fan House-Chennai.

1.) AS182SGD
Rs.25,290/- (Unit+Premier Stablizer+Delivery+Installation)

2.) AS183BGC - Stabilizer free model.
Rs.27,690/- (Unit+Delivery+Installation)

My requirement is a no-nonsense 1.5T AC around 25K all inclusive. I don't give a damn about, Turbo Cooling, Smart Saver, Bio Sleep etc. IMHO they are just nonsense.
Paid for the AS182SGD on 21st may @ Rathna Fan House. Delivery was promised on 23rd and installation on 24th. But the unit was delivered on 21st night itself! Impressed.

Installation happened only on 24th May. The provision for piping through the wall was already there and the compressor unit didn't need an angle to rest. The installers took less than an hour to install.

Pretty impressed with RFH. To my knowledge their pricing is one of the lowest in chennai and also the sales persons were well informed in comparison to e-zone, Vasanth & Co etc.

P.S:
1. O-General 1.5T 2* window AC costs about 27K @ RFH. That's not as expensive as I thought.
2. RFH was selling about 1K units/day in summer 2010 which is down to less than 500 units/day in 2011. Competition and electricity issues that plague the city and it's suburbs are the reasons cited.[/list]
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Old 24th May 2011, 16:10   #1898
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Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by rana_kirti View Post
does that essentially mean that if a person is ok with the ac doing 25-26 then he probably can go for a 1 ton ac instead of a 1.5 ton for a 150 sq ft room with the disadvantages being..

1. longer time to cool room. i guess a 1 ton will probably 10-15 mins more than a 1.5 ton to cool to 25-26 degrees from 42 degrees.

2. the 1 ton AC not being able to go below 25 degrees in a 150 sq ft room.

If the above is true then it might make a lot of sense for people who are OK with the above 2 points to go for a 1 ton AC instead of a 1.5 ton and save money on Purchase Cost and Electricity running costs.

What Say ?

Regards,

Rana
No. A 1 tonne a.c. cannot be put in a 150 sq.feet room and yes, a 1 tonne a.c. can be put in a 150 sq.feet room.

Various brands swear that their 1 tonner units are sufficient enough under all circumstances due to the powerful compressors. MHI, Ogeneral (use bigger compressors) and Toshiba for e.g.

If the a.c. is used in the day with a a hot roof and huge windows and lots of people, the utility bills will rise and the life of a.c. will go low. Too many bulbs and other heating devices will also add to the stress. If you use it for sleep at night or such then a 1 tonner is perfect. If you use it at work, Go for a 1.5. This does not apply to inverters as they function completely differently and one needs to take into factor the usage of the ac. Also With the walls, floors cooling down, a.c. efficiency increases.

And like many others said, there are lots of other ways to save electricity too.

My Ogeneral which I had purchased for a 140 sq.feet room always cut off way before since it was more powerful for the size of the room. So bigger a.c. is also equally bad for you.

Last edited by devarshi84 : 24th May 2011 at 16:14.
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Old 24th May 2011, 16:15   #1899
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Default Re: Which home/office AC (air conditioner) to buy ?

Just a minute folks. With the new refrigerant (R410/401) 1.5TR means 17,000 BTU per hour and not 18,000.
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Old 25th May 2011, 07:34   #1900
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Default Re: Which home/office AC (air conditioner) to buy ?

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Just a minute folks. With the new refrigerant (R410/401) 1.5TR means 17,000 BTU per hour and not 18,000.
Sir, how can a refrigerant change the definition of a standard unit of measurement?!
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Old 25th May 2011, 09:52   #1901
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Default Re: Which home/office AC (air conditioner) to buy ?

@anupmathur; Just look at the specs. The 1.5TR nominal units with the new refrigerant are all 17000Btu/hr. As I wrote in an earlier post, I guess the mechanical design of the compressors remains the same, but the newer refrigerant needs higher flows/pressures to get the same amount of cooling.

Bought one Hitachi RAV518ERD 5* Window unit (17,060 BTU/hr) for Rs.29,500 yesterday. Expect delivery today.
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Old 25th May 2011, 10:46   #1902
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by sgiitk View Post
Bought one Hitachi RAV518ERD 5* Window unit (17,060 BTU/hr) for Rs.29,500 yesterday. Expect delivery today.
This is an excellent unit Sanjay! Congratulations. It's the best window unit currently available. Have seen it in action in a room that faces the sea and faces the complete power of the afternoon Mumbai sun.
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Old 25th May 2011, 10:48   #1903
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by anupmathur View Post
Sir, how can a refrigerant change the definition of a standard unit of measurement?!
I think the tonnage of the AC is indicative and not actual. For example I have noted that the so called 1.5 ton units deliver as low as 1.2 tons and as high as 1.7 tons if you measure the cooling delivered.

In this case the manufacturers may be using the old designs, modified to take higher pressure, but in the process delivering less cooling.

http://www.fire.nist.gov/bfrlpubs/bu...PDF/b02186.pdf

This is an interesting article, amongst other things it concludes (page 7) that at high ambient temperatures (as in India) the R410a is less efficient compared to R22. So be prepared to shell out more for the R410a refrigerant based systems due to
1. Higher pressures require sturdier components and better joints
2. Cost of R410a refrigerant is more than R22
3. Lower efficiency at high ambient translates to a larger compressor
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Old 25th May 2011, 11:17   #1904
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I think the tonnage of the AC is indicative and not actual.
In this case the manufacturers may be using the old designs, modified to take higher pressure, but in the process delivering less cooling.
Naturally, this is what happens in the 1st Gen for the new refrigerant. You just 'beef up' the old lot with a minimum of mods.

Quote:
Originally Posted by Aroy View Post
the R410a is less efficient compared to R22. So be prepared to shell out more for the R410a refrigerant based systems due to
1. Higher pressures require sturdier components and better joints
2. Cost of R410a refrigerant is more than R22
3. Lower efficiency at high ambient translates to a larger compressor
I will say at the moment. Next gen may not be, since it will be optimised for R410a.
Cost of R22 will climb to cross R22 in due course. Same happened with R12 v R134!

I am not sure whether R410a has come into window units so far. Will check on arrival and report back.
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Old 25th May 2011, 19:48   #1905
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Congrats Sir. Kindly tell us the performance of this unit as this season temperature is already touching the records. Also let me know whether you bought the stabilizer as well?

Also I would like to share with you that the BTU of the HITACHI 5 star unit is 17060 and the 4 star unit are 17300.This was the main reason why I chose the Hitachi Summer Qc over the 5 star Quadracool one.
Kindly advice.

Regards,
Lalit Tyagi
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