Surviving Calcutta's super hot and humid summer last year, I finally made up my mind to go for Air Conditioners which are day by day becoming an essential equipment rather than luxury to middle class family like ours. With an ever increasing demand fueled with widely available EMI schemes, it has mooted variety of brands and products availability in the market. Some of the renowned brands that can be found in the market are Mitsubishi, Hitachi, Daikin, Panasonic, Sharp, LG, Carrier, O-General, Toshiba along with several indigenous brands like Voltas and BlueStar. Each of these brand offers non-Inverter air conditioners with variety of added features like inclusion of antibacterial air purifiers, anti-odour, etc where as the best of them having proper R&D facilities offers newer and much advanced technology like Inverter air conditioners.
In India room air conditioners are generally available from 0.8 to 2.5 Ton range denoting their cooling capacity class. Internationally the air conditioners are rated as 0.5, 1.0, 1.5, 2.0, 2.5 and 3 HP (Horse Power).
Below is a chart of the cooling capacity class:
0.5 HP = 6,000 BTU/Hr = 0.5 Ton
1.0 HP = 9,000 BTU/Hr = 0.8 Ton
1.5 HP = 12,000 BTU/Hr = 1.0 Ton
2.0 HP = 17,100 BTU/Hr = 1.5 Ton
2.5 HP = 24,000 BTU/Hr = 2.0 Ton
As a consumer it became very difficult for me to determine which type air conditioners to vouch for, I mean Inverters or non-Inverters, the one that provides the best bang for the buck and is also extremely energy efficient to counter the rise of per unit cost of electricity?
One way was to go relatively cheaper non-Inverter route where air conditioners are rated from 1 ~ 5 stars in terms of efficiency by Bureau of Energy Efficiency (BEE), a statutory body under the Indian Union Ministry of Power. Affixing BEE star label has been made mandatory by BEE to all the manufactures for the benefit of general public, showing the level of energy consumption by non-Inverter air conditioner both in terms of absolute values as well as equivalent number of stars varying from one to five, in accordance with BEE stipulation. The greater the number of stars on the label, higher the appliance energy efficiency and lower its electricity consumption. While selecting non-Inverter air conditioners refer to the BEE Star Rated Label affixed is must.
Energy Efficiency of Air Conditioner
Efficiency of an air conditioner is normally measured as Energy Efficiency Ratio (EER), which is the ratio of the cooling output, measured in British thermal units (BTU) per hour, to the power input (in Watts, and includes all inputs to compressor, fan motors and controls) to operate AC at standard rating conditions. This means a higher the EER, the more efficient the air conditioner is.
At times, EER is defined a little differently. The cooling capacity instead of being denoted in Btu/Hr is also denoted in Watts (1 BTU/Hr = 0.293 Watts). Thus EER is represented as Watts/ Watts or as a number without any units and will be assumed from now on.
EER Calculation of non-Inverter Air Conditioner
Non-Inverter Model: Hitachi i-Clean (RAU518ITDA)
Tonnage: 1.5 Ton
Star Rating: 5
Rated Cooling Capacity: 5274 watts
Total Power Drawn: 1524 watts
Rated EER: 5274/1524 = 3.46
So the higher the EER number better is its efficiency and more costly it’s going to be, due to the use of more advanced technology.
BEE Chart of star ratings applicable to air conditioners for 2012 ~ 2013
1 Star -> 2.5 to 2.69 EER
2 Star -> 2.7 to 2.89 EER
3 Star -> 2.9 to 3.09 EER
4 Star -> 3.1 to 3.29 EER
5 Star -> 3.3 and upwards EER
And for 2014 ~ 2015
1 Star -> 2.7 to 2.89 EER
2 Star -> 2.9 to 3.09 EER
3 Star -> 3.1 to 3.29 EER
4 Star -> 3.3 to 3.49 EER
5 Star -> 3.5 and upwards EER
Let us assume someone buys a 5-star rated non-Inverter air conditioner in 2011 with EER of 3.1. By 2012 the same AC becomes a 4-star since 5-star requirement is 3.3, by 2014 a 3-star since 5-star now requires 3.5 and by 2016 a 2-star since 5-star now requires 3.7. By 2018 the same AC becomes a pesky 1-star AC since 5-star now requires 3.9. For non-Inverters it generally takes seven years for the epic climb down form 5-star to 1-star.
So, we find EER star rating of non-Inverter air conditioners as an ever moving target and its star rating is respective to the year a particular model was released. This is very important to keep in mind while going for non-Inverter air conditioners.
The other and more expensive way was to go for Inverter Air Conditioners which are sophisticated piece of equipment. At the very start of an air conditioners operation, powerful cooling is required to reach the set temperature. After the set temperature is reached, less cooling is required to maintain it. A conventional non-Inverter air conditioner can only operate at a rated capacity which is below the maximum capacity but still too powerful to maintain the set temperature. Thus, in attempting to maintain set temperature non-Inverter air conditioners switches the compressor ON and OFF repeatedly. This results in wider temperature fluctuations leading to wasteful consumption of electrical energy.
The Inverter air conditioners on the other hand have a full-output operation mode to operate at maximum capacity as soon as they start thus reaching the targeted temperature faster than non-Inverter and when the set temperature is achieved drastically reduce energy consumption by going into energy-saving operation mode by varying the rotational speed of the compressor along with the indoor and outdoor fan motors for optimum performance at all times. This provides a highly precise method of maintaining the set temperature and drastically reduces wasteful cooling operation and energy consumption.
Advantages of Inverter Air Conditioners
To achieve this technical feat, in-built sensors from both indoor and outdoor units measuring temperature and humidity are processed at over 4000 times per second by Inverter air conditioners brain i.e. Digital Micro-computer Module which then maintains targeted room temperature and humidity by constantly controlling the voltage, current and frequency send to its highly energy efficient DC motor compressor and also sending commands to its highly sophisticated electronic pulse linear expansion valve to precisely control coolant pressure for more efficient heat exchange. In conjunction to the above activities the electronic module also controls speed of the indoor and outdoor fan units which contain high quality DC motors. DC motors are more efficient and save energy over conventional AC motors used in non-Inverters since they use magnetic force to operate.
'The Brain' of an Inverter Air Conditioner (Digital Micro-computer Module)
One has to understand that technology comes at a price. The hard earned money one pays for Inverter air conditioners are put in using much better components which never came with non-Inverters, reaping their benefits in terms performance and efficiency with significant reduction in power consumption, not the mentioned the prolonged life-span with use of high quality materials. Also Inverter air conditioners produce no humidity when adjusting room temperature. This is very important since it is the moisture removed from the room which actually produces the feeling of cooling. If the air conditioners can effectively remove enough moisture from the room it will produce a feeling of comfort.
'The Brain' of Inverter Air Conditioners are generally located on the Outdoor Units and their heatsinks are cooled by the ODU fan
Since I plan for extended use on a daily basis, I decided for Inverter ones over cheaper non-Inverters. I was astounded to learn in Japan almost all air conditioners are Inverter's where as in India the same Japanese air conditioner companies sell low cost non-Inverter, 5 star rated air conditioners at same price of Inverter air conditioners. The reason I believe is people awareness, very few people know about the real benefits Inverter's offer in terms of cooling performance, efficiency and low power consumption under part load conditions. This companies takes advantage of the situation and garner fat profit margins by selling 2~5 star rated age old technology.
It have been over four months since I installed two 1.5 Ton Sharp Eco-Inverter (Model no: AH-XP18MV) air conditioners. These includes in-built Plusmacluster air purifier technology.
Personally, I am not the kind of person who buys a consumer product because Mr. ‘X’ had recommended buying product ‘Y’ from manufacturer ‘Z’. After haplessly wandering in the forums for a month or so I understood people in India being unaware are still happily using stone age star rated non-Inverter technology filled with R22 refrigerant gas where as the rest of the developed countries have moved on to a whole new level with Inverters, filled with energy efficient and environmentally friendly R410A refrigerant gas.
In my vision, Inverters are the way to go, no matter if they cost more or less. In Japan, people do not think about how many hours they are going to use them, they just buy Inverter air conditioners. Thus all room air conditioners in Japan are Inverters. They not only look at the money aspect, they also save precious energy and environment.
After some six months of market study, personal experiences while visiting various dealers/ showrooms I reached to the conclusion there are NO ‘number one ’ or ‘number two ’ among air conditioner manufacturers. Some companies like Hitachi & Daikin are revered in India and sale self advertised 'premium quality ' air conditioners due to their face value where as general consumer appliance manufacturers like LG & Samsung have their range from the very bottom to the top. Hitachi have an unprecedented reputation in India which they built through the last two decades when there was simply no competition at their level by providing excellent products at sky high prices. Amazingly even today with their extra-high quoted price people go by hype and buy them blindly because it’s a 'Hitachi'.
But buyers like me who have done a through market study and want the most out of the rupee find the current landscape to have dramatically changed with multiple previously unknown international air conditioner companies jumping in the lucrative and nascent Indian air conditioner market raising the performance bar higher every year with cut throat competition. This is a boon for us buyers. In the Inverter air conditioner market I find Hitachi and Daikin as just two players along with Sharp, Panasonic, LG, Mitsubishi and Carrier.
After personally experiencing the Sharp, LG and Hitachi Inverter air conditioners, I found Sharp and LG's to be much superior than the similar Hitachi/Daikin ones in terms of performance, reliability and product quality. LG uses the most advanced technology of all Inverter air conditioners currently available in India and one will be a lucky to get their 1.5 Ton version at less than INR 54K. Also the product qualities of LG Inverter air conditioners are in altogether different premium level w.r.t. their non-Inverter air conditioners models.
But the real deal is how much you get at a certain price point (cost versus efficiency) and from that perspective Sharp Inverter's are truly hard to beat.
Indoor Unit [IDU]: Sharp AH-XP18MV
Outdoor Unit [ODU]: Sharp AU-X18MV
Cooling Capacity Range [kW]: (1.6 - 5.27 - 6)
Cooling Capacity Range [BTU/Hr]: (5,460 - 18,000 - 20,500)
Rated Cooling Capacity: 5.27 kW/ 18,000 BTU/Hr
Rated Power Consumption: 1,440 watts
Rated EER (W/W): 3.66
Indoor Airflow Rate (CMM): 16.8
Indoor Noise Level (High): 44 dB
Outdoor Noise Level (High): 53 dB
Plasmacluster Air Purifier: Available
Refrigerant Gas: R410A
IDU Weight: 12 kg
ODU Weight: 35 kg
My 1.5 Ton Sharp AH-XP18MV Inverter air conditioner come fully imported from Thailand with an MRP of INR 50K. The indoor unit looks gorgeous, has amazing cooling performance capability and just oozes quality. Being the premium 1.5 Ton model, Sharp also have their patented Plasmacluster air purifier built inside it. If one can really bargain well he will get them for 43K. And if one can really really bargain like me, he will get them at 41K, below which the dealer will simply refuse to sale since their profit margin falls below 1K. In comparison the best price I got for the Hitachi i-Clean non-Inverter 1.5 Ton, 5 star air conditioner was a sky high 42K where as their i-Tec Inverter 1.5 Ton costs an earth shattering 56K!!!
I immediately dumped the Hitachi for their un-justified pricing and went for Sharp Inverters, other reasons being their excellent customer support and after sales service provided in Kolkata.
Sharp Plasmacluster Air Purifier Mechanism
I was thus able to get two Sharp AH-XP18MV, 1.5 tonners at 82K along with complete free installation kits. After adding two pairs of best after market ODU brackets and installation charge, total damage to my wallet rested at INR 87K.
One of the key reasons opting for Sharp's other than performance and being a true VFM product was that they provide the best and safest installation kits out here, the liquid and gas side copper tubing are of 4 meters in length having class leading 0.8mm thickness which is super thick along with superior 4 meters of XPE insulation(white), 4 meters of 4-core electric wire, 4 meters of drain pipe et-al. Our installer (he is a very experienced professional being in this air conditioner installation business for over 30 years) said the pipes will last a lifetime and no company even Daikin & Hitachi provides the copper pipes of similar quality to connect the indoor unit to the outdoor unit as provided by Sharp.
Nature inspired NatureWing Cross-flow Indoor Fan
Indoor Unit (IDU)
I found Sharp AH-XP18MV is using a new concept on their cross-flow fan design which they say is inspired by nature, called NatureWing. To me its just a new marketing name. The fan feature blades modeled on the shape of dragonfly’s wings which have ridged surfaces that generate minuscule air eddies during flight. These eddies function like ball bearings to make their flight smoother with less effort. These new dragonfly wing shaped fan blades are said to harnesses the flow of air a bit better than previous designs to boost air circulation efficiency. I find the indoor units are super quite in Auto Mode and only when I select Super Jet function do I hear jet stream of air gushing out!!! In the end AH-XP18MV indoor unit's NatureWing concept is worth the salt as it is capable of achieving a max airflow rate of 16.8 CMM (cubic meter per minute) resulting in strong chilling windblasts. In contrast Carrier can do a max of 14.3, Daikin a 14.7, Mitsubishi a 15.1 and Hitachi a 16.7 with their respective 1.5 Ton Inverter models.
Outdoor Unit (ODU)
While comparing similar 1.5 Ton Inverter outdoor units, I found Sharp is using a bigger and higher cooling capacity Rotary Compressor for its class. With the compressor having quite advanced Torque Control Technology controlling load torque generated by the compressor rotation by combing it with the torque generated by the compressor's DC motor, substantially reducing noise and vibration of the compressor contributing to higher efficiency, and thus higher energy savings. The compressor drive technology is also quite advanced which adopts a 180° conductance sine wave instead of the conventional 120° conductance waveform used by its competitors resulting in smoothing of compressor motor rotation at high RPM (revolutions per minute). Lastly, the compressor unit of this Sharp Inverter comes enclosed inside an acoustic jacket to eliminate noise and makes the outdoor unit very quiet. It is so quite that it becomes hard for me to guess from a distance whether it is running or not until the ODU fan starts rotating.
Unlike the cheaper capillary used in non-Inverter air conditioners which allows free flow of the refrigerant gas, the Sharp Inverter's controls the flow according to the load needed by using technically superior and much more performance oriented Electronic Pulse Linear Expansion Valve. It has numerous settings to precisely control refrigerant flow which helps in drastically improving the efficiency of the desired cooling. It also helps in maintaining room temperature within a near accurate 0.5 degree centigrade variation of the set temperature unlike typical temperature change that occurs with non-Inverter air conditioners, thus reducing energy consumption.
Electronic Pulse Linear Expansion Valve
While Mitsubishi, Daikin, Carrier & Panasonic Inverter air conditioners have a rated 17,100 BTU/Hr cooling capacity for their 1.5 Ton class, Sharp uses a compressor which being rated at 18,000 BTU/Hr equates to a 1.6 Ton Inverter. So +1 to Sharp.
On the other hand while comparing with 1.5 Ton non-Inverter models with fixed rated 17,100 BTU/Hr cooling capacity, I find this 1.5 Ton Sharp Inverter have a maximum cooling capacity of 20,500 BTU/Hr equating to a 1.8 Ton non-Inverter!!! This implies the Sharp Inverter will have a full-output operation mode of a 1.8 Ton non-Inverter to operate at maximum capacity as soon as it starts thus reaching the targeted temperature faster than a 1.5 Ton non-Inverter and then gradually reduce its energy consumption by coming down to its rated cooling capacity of 1.6 Ton. When the set temperature is achieved it will drastically reduce energy consumption by going to energy-saving operation mode and rolling down to a minimum cooling capacity of just 5,460 BTU/Hr which equates to an amazingly tiny 0.4 Ton non-Inverter. This is the reason why dealers say a 1.5 Ton Inverter will suffice for a 2 Ton non-Inverter. So +10 to Inverter technology.
One of the key reason to opt for Sharp Inverters were the use of complete all-aluminum, galvanic corrosion resistant, more efficient & durable condensers having canalicular tubing resulting in superior refrigerant flow velocity, improved heat exchange efficiency and decreased heat transfer loss from tube to fin in their outdoor units. This modern condensers are costlier as well as lighter to age old, bulky, less efficient copper-aluminum condensers with circular tubing that other manufacturers like Hitachi, Daikin and Panasonic uses to save cost.
All-Aluminium Canalicular Tubed Condenser VS Copper-Aluminium Circular Tubed Condenser
All-aluminium canalicular tubed condensers are definitely the next step towards advanced technology and improved efficiency where the refrigerant enters multiple tubes at the same time, therefore enhancing the air conditioners performance and reduce the power consumption. Such efficient condensers with high heat capacity have long been used in cars and are designed with increased surface area and less resistance to airflow enabling improved thermal efficiency and much better performance compared to copper-aluminium circular tubed condensers. They also call for special carefully designed outdoor condenser fans for proper heat expulsion. Sharp says AH-XP18MV employs a newly shaped fan blade which is based on the aeronautical theories of NASA and is run by a highly efficient DC fan motor. The redesigned fan blade cross-section with an ideal streamline is said to increase “lift” (the principle by which airplanes fly), thereby achieving a high rotation efficiency of 120–170% compared to their previous outdoor fans having superior blowing performance.
Being all-aluminum the outdoor units of Sharp 1.5 Ton Inverter's weighs just 35 kilos having a much smaller footprint with reduced weight. In contrast the similar 1.5 Ton Inverter outdoor units from Daikin are much bigger and weigh 47 kilos!!! Due to use of all-aluminum canalicular tubing, Sharp 1.5 Ton Inverter requires just 700 grams of R410A refrigerant gas to cool while the same 1.5 Ton Inverter air conditioners from Hitachi, Daikin & Panasonic using circular tubed copper-aluminum condensers requires 1.5 kg of R410A gas to cool the same area!!!
Amazingly with even less than half the refrigerant gas available this Sharp 1.5 Ton Inverter air conditioner still comes out on top with class leading cooling performance scientifically measured as EER of 3.66 (W/W) and at the same time be more environmentally conscious by using less gas. Performance & efficiency speaks. In contrast the Daikin could manage an EER of just 3.23 while Hitachi does a little better of EER of 3.51. Mind you both of them cost a minimum of 15K over this Sharp!!!
Rated EER of some 1.5 Ton Inverter air conditioners available in India (Higher value means more energy efficient):
Sharp (AH-XP18MV): 3.66
Hitachi (RAU018EQE): 3.51
LG (BS-Q186C7M1): 3.34
Carrier (42CVSR018-703): 3.31
Panasonic (CS-S18NKYP): 3.27
Daikin (FTKS50): 3.23
Mitsubishi Electric (MSY-GE18VA): 3.12
Sharp Inverters not only have the best cooling performance in 1.5 Ton category, it has one of the widest cooling capacity range. As Inverter air conditioners are constantly varying its cooling capacity according to needs, when set temperature is achieved the Hitachi will climb down from its rated cooling capacity 5.33 kW to minimum of 2.37 kW to save power consumption, Daikin will climb even lower from their rated 5 kW to 1.7 kW to save a little more than Hitachi while Sharp will climb down from rated 5.27 kW to even lower 1.6 kW and consume even less power under part load.
Comparison of cooling capacity range (Min - Rated - Max):
LG (BS-Q186C7M1): (0.9 - 5.2 - 6) kW. Range: 6 - 0.9 = 5.10 kW
Sharp (AH-XP18MV): (1.6 - 5.27 - 6) kW. Range: 6 - 1.6 = 4.40 kW
Daikin (FTKS50): (1.7 - 5 - 6) kW. Range: 6 - 1.7 = 4.30 kW
Mitsubishi (MSY-GE18VA): (1.4 - 5 - 5.4) kW. Range: 5.4 - 1.4 = 4 kW
Hitachi (RAU018EQE): (2.37 - 5.33 - 6.04) kW. Range: 6.04 - 2.37 = 3.67 kW
LG Inverters are simply unbeatable with their widest cooling capacity range of 5.10 kW and under part load conditions can come down from their rated 5.2 kW to an amazing 0.9 kW consuming very very less power. Hats off to LG to perform such a technically daunting task for controlling a 6 kW compressor to run smoothly at just 0.9 kW!!!
An important aspect to note is Inverter air conditioners are not star rated in India due to their variable cooling capacity and power consumption which results to variable energy efficiency. They are more or less super star rated!!!
EER Calculation of Inverter Air Conditioner
Inverter Model: Hitachi i-TEC (RAU018EQE)
Tonnage: 1.5 Ton
Star Rating: Not Applicable
Cooling Capacity (Min/ Rated/ Max): 2370/ 5330/ 6040 watts
Total Power Drawn (Min/ Rated/ Max): 530/ 1520/ 1850 watts
Varying EER: 2370/ 530, 5330/1520, 6040/1850 = 4.47/ 3.51/ 3.27
From the above calculation we find the Hitachi RAU018EQE Inverter model having an EER which is constantly varying between 3.27 to 4.47, while their non-Inverter model discussed above always having a constant EER of 3.46. In other words the Inverters have varying efficiency and as much the air conditioners can reduce its cooling capacity greater will be their overall efficiency. But it is tough to do from a technical point of view.
Inverter air conditioner for every three hours of operation are said to reduce power consumption w.r.t. a non-Inverter air conditioner of same capacity by roughly:
30% in comparison to a 5 star rated
35% in comparison to a 4 star rated
40% in comparison to a 3 star rated
45% in comparison to a 2 star rated
50% in comparison to a 1 star rated
According to Bureau of Energy Efficiency (BEE) for non Inverter air conditioners to qualify for a 5 star rating a minimum EER as below is required:
2012-2013 -> 3.3 (W/W), 2014-2015 -> 3.5 (W/W), 2016-2017 -> 3.7 (W/W)
My Sharp AH-XP18MV -> 3.66 (W/W) = ~ 3.7 (W/W)
Standing in 2012, my Sharp AH-XP18MV Inverter air conditioners not only surpasses the 5 star requirement of 2015 with flying colors, it also matches 5 star requirement of 2017!!! And that too it is an Inverter which means it will provide better cooling performance than a 5 star rated non Inverter air conditioner of 2017 while consuming even less power.
Long live Inverter air conditioners. I advice everyone to go for Inverter air conditioners eyes closed, it is the future.
One of my Sharp AH-XP18MV, 1.5 Ton Eco Inverter Air Conditioner with In-Built Plasmacluster Air Purifier
My other Sharp AH-XP18MV
Front View (IDU)
Side View (IDU)
Display shows power consumption instead of indoor air temperature. 0.1kw means equal or less than 100 watts consumed (Running in Auto mode)
Full blast with Super Jet function + Plasmacluster air purifier in Auto mode. Varying power consumption now showing 0.8 kW = 800 watts
Some other shots of the Indoor Unit
Remote Control Unit
Sharp AU-X18MV [Outdoor Unit]
Sharp AU-X18MV outdoor unit implementing much advanced all-aluminum condenser with canalicular tubing
Since finished installing the Sharp Inverter air conditioners during last winter months I refrain to provide a conclusive personal review as of now. Even though the air conditioners are chilling the rooms in no time, let the summer heat of May and June arrive and then only I believe a conclusive personal review can be written. Follow this thread for future updates.
Anyway I just thought it will be useful to provide the link below which to me was very useful and helped me in decision making. It is regarding the real personal experiences of a FM using the same Sharp Inverter air conditioner as above.
Link: HifiVision: Recommend an inverter based AC (some prices inside)