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Old 04-05-2016, 01:39 PM   #7313
WussRedXLi
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Join Date: Jun 2001
Posts: 59,416
A lot of assumptions about cost savings from 5 vs 2 tick. Use this calculator. There's another nea link, can't find it now. But it's useful.

There's been much talk about the mitsubishi 5 tick being lousier (lower powered) than the 2 tick because it's 6.6 kW vs 7.52 kW. Find it hard to believe the japanese mitsubishi engineers are as incompetent as people seem to suggest. I doubt it's that simple. Could very well be the 5 tick having a more efficient design and cooling just as well, but using less power.

Assuming air con lasts for 7 years with heavy usage (8 hours daily), system 4 mitsubishi 5 tick (4G28) vs 2 tick (4A28). 5 tick saves $3000


Do your own calculations here:
http://www.e2singapore.gov.sg/Househ...alculator.aspx

More info here:
http://www.e2singapore.gov.sg/Househ...alculator.aspx

If you use the air con for at least 8 hours daily, 5 ticks will surely save you a ton of money across the years.
The calculator is a good easy tool, but it's based on a pretty huge usage pattern, probably a temperature set pretty low or the heat load is high. Heat load high can come from number of pax in the room, high number of electrical appliances, or the walls/floors suck in insulation. (I know some old resale units are really very lossy )


I just quote it and DIY some calculations, better to see it from another angle in terms of efficiency percentage which translates to kWh savings per month/year/7 years.


Panasonic CU-PS12NKZ 2 ticks.
Cooling capacity 4kW. Amps draw 4.2A

Panasonic CU-XS12RKZ 4 ticks
Cooling capacity same 4kW. Amps draw 3.7A

I didn't manage to find 5 ticks for Panasonics.
Both are inverters.

Difference = 13% in electrical consumption between 2 and 4 ticks

If your monthly aircon bill for this 12k FCU is $70 (4-ticks), then it's $79 for the 4-ticks, for the aircon component with a 13% difference. (that's a decent amt of usage - i use much less). Or 108 yearly. Or 756 for 7 years. That is one room with 12k btu/hr FCU (pretty powerful....maybe big MBR)



I use another model that's 9000 btu/hr and folks would be able to relate better with a 9k FCU.

Panasonic CU-XS9RKZ 4 ticks
3.4kW cooling. 2.7A. 840W full load.
(3.2kW cooling needs about 2.55A?)

Panasonic CU-PS9NKZ 2 ticks
3.2kW cooling. 3.3 amps

29% difference between 2 and 4 ticks in this scenario.


If your monthly aircon bill for this 1 room is $60 thereabouts for the 4-ticks, expect $77 for the 2 ticks 9k FCU. $204 diff per year, 1428 diff per 7 years.


How much is $60 worth of electricity? It is 0.1768/kWh now, add 7% gst and it's $0.1892/kWh. $60 is 317kWh, 4-ticks, or 317/30 = 10.56 kWh per day.
The 4-tick system just manages 840W full load, 8hrs usage is just 6.72kWh daily. 3.4kW cooling capacity, or 10,900 btu/hr system.
To get 10.56kWh daily usage so as to achieve that $60 electrical AC bill per room, the operation at full load non-stop would be 12.5 hrs daily



I do not think one can gun the darn 10,900 btu/hr aircon 12.5hrs @ full capacity in a BTO room without freezing to uncomfortable levels. ie set it at 16 deg C


In real life, the aircon usage, at least for me, is way lesser than what is shown by the .gov.sg calculator.
ie just go by percentages. Take a max of 30% (it could just be 13%. whatever). If your bill aircon bill is just $25 per room monthly and you have 2 rooms AC nightly, then it's a $50 AC bill montly.
30% diff is 15 dollars difference. It will be less if it's 13%
7 years = $1260 for these 2 aircon rooms.
(in my case, it's probably lower than even $1000 for 2 rooms over 7 years)

Not sure what is the price difference between the 4 or 5 and 2 ticks system though. But i guess it's less than $1,000 nowadays, last time it was way more i think. So i guess it still pays somewhat to go for the 4 or 5 ticks, all things being equal.
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Last edited by WussRedXLi; 04-05-2016 at 02:34 PM..
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