Inverter vs non- Inverter split AC

[crossword]

Hi,
I want to buy a split Ac for my living room, which is 25 by 12 feet, or 300 square feet.

One dealer told me I should buy the Sharp Inverter 2 ton AC since it would cut electricity costs. The Sharp Ac costs Rs 56,000.

Another dealer told me that theres a significant savings in electricity only if you use the Inverter Ac for over 8 hours a day. I use it for about 6 hours a day for 4 months in a year.

my living room opens up to a small passageway that leads to the other rooms. We have covered this opening with curtains. He says the curtains are not air-tight enough and thus will make the inverter work much harder and I’ll get much higher bills instead of lower.

He suggested I buy the Panasonic 3 star 2 ton Ac which costs Rs 39,000.

So, if I buy the inverter Ac, I’ll spend Rs 17,000 more.

Will the amount I save on electricity make it worth my paying Rs 17,000 more? or is it, as the second dealer told me, that I will not get significant savings since I use it less than 8 hours a day and since the curtains will make the inverter work so much harder than my electricity costs will anyway increase?

I would appreciate advice from anyone who has experience with inverter ACs. Thanks a lot.

 

[Crazy_Eddy]

Having only curtains will affect both types of A/Cs. Unless your non-inverter A/C is not working, there's no reason it wouldn't sense a drop in temperature and be running overtime as well.

Anyway the returns might not be visible on an inverter with your limited usage. Assuming you spend Rs. 1000 on electricity for a normal A/c per month, an Inverter would net a roughly 30% saving (optimal scenario), which means you save 300 bucks a month. 4 months a year = savings of Rs. 1.2K a year. You would need 15 years to actually recover your investment at this rate.

Further the Sharp Inverter A/c has a few extras like an Ioniser and better build quality. So you need to weigh in if you want to spend extra for that.

 

[crossword]

Thanks for your answer. I live in Gujarat and our electricity bills are high. I get as high as Rs 3,500 per month bill in summer.

We also use a 300 liter Godrej Frostfree fridge and run the washing machine every day for one full load. I don’t know how much these 2 items contribute to our bill and how much is due to the AC.

And I don’t know how much an inverter would save of that.

I also read the savings of an inverter kick in only if you use it continuously for several hours. We often use for a couple of hours, then put off for half an hour to give the Ac a rest and save on the bill. So again I don’t know if the inverter would be of any use in such a situation.

 

[RishiGuru]

According to Bureau of Energy Efficiency (BEE) for non inverter air conditioners to qualify for a 5 star rating a minimum cooling performance measured in COP as below is required:

2010-2011 -> 3.1 (W/W)
2012-2013 -> 3.3 (W/W)
2014-2015 -> 3.5 (W/W)
2016-2017 -> 3.7 (W/W)

Some one buys a 5-star rated non inverter air conditioner in 2011 with COP of 3.1.

By 2012 the same AC becomes a 4-star since 5-star now requires 3.3.

By 2014 the same AC becomes a 3-star since 5-star now requires 3.5.

By 2016 the same AC becomes a 2-star since 5-star now requires 3.7.

An inverter AC from a reputed manufacturer released way back in 2011 had a COP of 3.66. Being an inverter AC it will surpass the standards set by 5-star in 2016 to 2017.

Amazing isn't it!!!

 

[Chiranjib]

Thanks for your answer. I live in Gujarat and our electricity bills are high. I get as high as Rs 3,500 per month bill in summer.

We also use a 300 liter Godrej Frostfree fridge and run the washing machine every day for one full load. I don’t know how much these 2 items contribute to our bill and how much is due to the AC.

And I don’t know how much an inverter would save of that.

I also read the savings of an inverter kick in only if you use it continuously for several hours. We often use for a couple of hours, then put off for half an hour to give the Ac a rest and save on the bill. So again I don’t know if the inverter would be of any use in such a situation.

Turning off the AC for half an hour is not a good thing to do from the viewpoint of saving electricity. Some tips to save on electricity bills:
AC: Run it continuously for the required period. Set temperature around 24-25C for optimal comfort and savings. Clean the IDU filter and ODU heat exchanger periodically.
Refrigerator: Keep it loaded (full). Do not switch off for small durations to save on electricity.
Washing Machine: Which machine you have? If it is a fully automatic one, you can set it at a lower heat setting (40-45C is optimal) and optimize washing time by choosing the program prudently.

Regarding your query, it is true that an inverter AC provides substantial savings, but only under continuous, substantial usage. I think the Panasonic model makes better sense to go for, since you'll be running the AC for only 4 months a year on an average of 6 hours a day. If you really want a low-cost cooling solution, you can take a look at 1.5T Panasonic Cube AC (cooling capacity is around 1.8T). I think it can cover 300 sq.ft of cooling space by working overtime (take another opinion on this) and the initial savings in purchase price will take care of the increased electricity consumption.

 

[TheIndian]

This is a no brainer, with your limited usage, it makes no sense spending money on an inverter unless you see the usage pattern changing in the coming years. BTW I do think 1.5 ton inverter will suffice, consider that in the equation too. (1.5 inverter v/s 2 ton regular)

Also go for 2 tons, since its in the living room, you are bound to have guests at some time or the other, that will need more cooling then what the cube can do, and better air throw.

 

[crossword]

Thanks so much for all your answers. Actually I am wondering if my 300 sq ft room even needs a 2ton Ac. The dealer said I must buy a 2 ton inverter and if I buy a 2 ton non-inverter I will need another 1 ton AC also. So, 3 tons in all.

I think thats nonsense. Someone told me he uses a 1.5 ton non inverter to cool his 700 sq ft living cum dining room. and he said he doesn’t get bigger bills.

But all dealers say if you have an AC that is too small for the room, the AC has to work harder to cool and you will get bigger bills.

What do you guys think? Do you really get bigger bills is the AC is smaller than the room size demands?

I don’t need the atmosphere of room to be like a fridge. I don’t need extreme cooling. I feel very cold after a while if the Ac is too powerful.

I googled 1.5T Panasonic Cube AC since Chiranjib recommended it. actually no dealer has mentioned this model to me. I googled and saw Panasonic ACs have some really bad reviews. Though also some good ones.

If I’m going for a 1.5 or even 2 tons non inverter AC, would Panasonic really be the best model? I’m looking for something that is no only reasonably priced but also works well.

What about Sharp? I read in another thread that Sharp has the best strongest thickest copper piping.

 

[RishiGuru]

I am wondering if my 300 sq ft room even needs a 2ton Ac. The dealer said I must buy a 2 ton inverter and if I buy a 2 ton non-inverter I will need another 1 ton AC also. So, 3 tons in all. I think thats nonsense. .... If I’m going for a 1.5 or even 2 tons non inverter AC....

I would have gone for a 2 ton inverter AC which can easily cool upto 290 sqft area with ease if is not the top floor. The premium I will pay for the inverter will be reaped within the next two years even if I intend to use it for just six hours a day for nine months of a year.

 

[Crazy_Eddy]

The dealer said I must buy a 2 ton inverter and if I buy a 2 ton non-inverter I will need another 1 ton AC also. So, 3 tons in all.

I think thats nonsense. Someone told me he uses a 1.5 ton non inverter to cool his 700 sq ft living cum dining room. and he said he doesn’t get bigger bills.

But all dealers say if you have an AC that is too small for the room, the AC has to work harder to cool and you will get bigger bills.

Find a new dealer, both of them seem keen on pushing what they have . An inverter's compressor can work a little over spec (usually ~10%), but its only so it can cool the room faster and switch to lower speeds sooner; its not intended as a replacement for higher capacities. The irony is that efficiency improves when a non-inverter A/c works longer, each time the compressor turns on (after the thermostat cuts it off) it wastes energy. So you need to find the right balance and not over-spec a non-inverter A/c.

The premium I will pay for the inverter will be reaped within the next two years even if I intend to use it for just six hours a day for nine months of a year.

Highly doubt it. At that rate he'd need to save nearly 1k a month, and even ideal tests cite only a 30% saving, which means he'd have to be spending 3k a month on one A/c alone. He probably already has a few A/cs and his all inclusive bill is still only 3.5k. Plus he says he will use it only 4 months a year.

 

[crossword]

Yes I live on the top floor of a 4 floor apartment building. So you mean the top floor gets hottest? Because the sun hits it?

I have only one AC and will use only one.

 

[Crazy_Eddy]

Yes I live on the top floor of a 4 floor apartment building. So you mean the top floor gets hottest? Because the sun hits it?

Yeah. Another floor above would act like a layer of insulation.

I have only one AC and will use only one.

You mean you will use only the new AC? Or do you mean 1 + the new AC?

What are Gujarat's electricity tariffs like? I made a rough assumption based on Chennai's Rs. 5.75 per unit rate. Assuming Gujarat rates are about the same I still don't think you will see a RoI with Inverter ACs with your sort of usage.

 

[crossword]

I will sell the old AC and will use only the new AC.

I assume that a 2 ton AC will naturally consume more power than a 1.5 ton one and thus, I will get higher bills?

When I asked my dealer that he said no, you won't get significantly higher bills. He said it will use more power only if the AC is too small for the room it is in, cos then it has to work harder. Is that true?

- - - Updated - - -

“The irony is that efficiency improves when a non-inverter A/c works longer, each time the compressor turns on (after the thermostat cuts it off) it wastes energy. So you need to find the right balance and not over-spec a non-inverter A/c.”

So if I use a non inverter or even inverter AC for 2 or 3 hours and then shut it off for one hour, I won't be saving any bills at all?

 

[Crazy_Eddy]

I assume that a 2 ton AC will naturally consume more power than a 1.5 ton one and thus, I will get higher bills?

Yeah, but by how much depends on how efficient your 1.5 ton was compared to the newer 2.0 ton, and what sort of usage it was seeing.

So if I use a non inverter or even inverter AC for 2 or 3 hours and then shut it off for one hour, I won't be saving any bills at all?

An inverter AC reaches high efficiency only by having the compressor *always* running, just at lower speeds. So turning off an inverter AC every few hours defeats its design. A non inverter AC might see some saving, but seems inconvenient turning an a/c on and off every few hours.

 

[RishiGuru]

@crossword

If you are on a tight budget and intent for limited use lasting a few months of a year go for non-inverter ACs. Else inverter AC which are definitely the future. Remember for every three hours of operation an inverter AC of same capacity will reduce power consumption by roughly:

30% in comparison to a 5 star rated non-inverter AC
35% in comparison to a 4 star rated non-inverter AC
40% in comparison to a 3 star rated non-inverter AC
45% in comparison to a 2 star rated non-inverter AC
50% in comparison to a 1 star rated non-inverter AC

Now it is upto you to decide. Best of luck.

 

[Crazy_Eddy]

Taking a Panasonic 3-star 2 ton AC (Model : CS-YC24PKY) :-

kw	compressor run-time	cost per unit	no of hours	no of days	cost per month
2.17	0.75	5.75	6	30	1684.46

40% saving on 1684.46 = 673.79. Rs. 17,000/673.79 = ~25 months. At 4 months a year -> 6 years. (Please correct if i've missed something :ashamed: )

I guess almost worth it assuming you do see the 40% savings in the real world, plus you don't need to bother turning it on-off and there's the extras that the Sharp has

 

[crossword]

Thanks again, everyone. I finally saw the 1.5T Panasonic Cube AC in a store.

I see it is around Rs 5000 cheaper than a 1.5T non inverter split.

And it seems to have a much larger surface area.

BUT it has no swing at all. most split ACs have only a 2 way swing, ie up and down. a few have a 4 way, side to side.

But the Cube has no swing. Which must be why its cheaper. Will the lack of swing be a serious problem? I suppose because of the lack of swing it will take longer to cool a room? those who are in the direct line of the Cube wil get cool but those at one side of the room will not.

Has anyone had a Cube AC and can you tell me how well it works to cool the entire room? thanks.

Also, for how many years has the Cube been around? If it’s a new invention, only around one year or so, that may not be enough time to know whether this model shows flaws after a few years.

 

[skoka123]

Hi OP,

I had a Hitachi Atom 2T in a 300 Sft room (a pretty large bedroom). I have replaced it with a Daikin 2T inverter model. I use it for 8 hours every night over a period of 4 months. The power tariff in AP is pretty high. I can say for sure that I have seen a great reduction in power bills. I do not want to get into the arguments of savings Vs upfront cost difference etc. Just bear in mind that an inverter model will use 40% less power than a 3-Star non-inverter model. In fact an inverter model consumes less power than a 5-star non-inverter model but the 5-star models are close to the price of inverter models.

I suggest that you not go to the dealers. Post a query on the Daikin's website or call their customer support for dealer numbers. Usually they give your reference to the dealers and then the dealers call you or you can call the dealers/distributors. This way you can shop over phone and bargain for the best price. I got my Daikin 2T AC for 43K last year. In total with the cost of the stabilizer, copper tubing, installation it came to 46.5K.

Apart from Daikin, another brand I would suggest is Mitsubishi. Buy the one from Mitsubishi Heavy Electricals and not Mitusbishi Air Conditioners. They are different in quality. Again, there are many dealers for Mitsubishi and you can get the dealers to compete for your order.

AC Sizing:
It is critical that you get the sizing of the AC right for your room in case of non inverter models (holds good for inverter models too). In case the AC is too big then the room gets cool too soon and the compressor switches off. In case it is too small it takes too long to cool plus the AC will struggle to keep the room cool resulting in the compressor running continuously. If you happen to be close to the air draft from the AC you will be too cold.

Remember that the conventional ACs are on/off mode w.r.t the compressor. I usually set the room temperature at 26C. The non-inverter models will cool until it is around 23-24C, sometimes even to 22C if the room is long, before the compressor is turned off. Then it will switch on when the temp is around 27-28C. There is a constant temp difference of 5C. The usual charade used to be to pull the blanket when the compressor was on and then take it off once the compressor stops. In effect there is disturbed sleep though one may not notice it.

In case of a inverter model, once the set temperature is achieved the compressor runs at 30% to 40% load to keep up with the temperature loss to maintain the set temperature. This results in near constant room temperature and better quality of sleep. I am not going into the humidity factor for now. The reason it is known as an inverter model is the current is inverted from AC to DC to run the DC compressor motor (just in case you are wondering why the normal ACs can't run at 30% load).

I hope this helps you. For me, apart from economics the quality of cooling is a big factor going for inverter models.

Thanks,
Srikanth

 

[crossword]

Thanks a lot. What you say made me consider inverter Ac again. But alas it is expensive and I am really going for something cheaper

But your info is very useful. If I can afford a more expensive one in the future I will go for an inverter model.

 

[PDIC]

hello techenclave,
i want to buy a 1.5 ton split ac 5 for my clinic (waiting area of patients )?
working of ac will be throught out year- 5-6 hrs in the morning & 3 hrs in evening (in between switching off ac)
plz reply regarding following points:
1) 5 star or invertor ac ? cost diff is only 7-8000 -so is it justified?
2) does invertor ac hav to work continously or is it fine with my requirement?
3) for both which company - panasonic , diakin or hitachi?
4) in short 5 star or invertor- which will be cost effective?
thanking you

 

[Demon_Ryu]

hello techenclave,
i want to buy a 1.5 ton split ac 5 for my clinic (waiting area of patients )?
working of ac will be throught out year- 5-6 hrs in the morning & 3 hrs in evening (in between switching off ac)
plz reply regarding following points:
1) 5 star or invertor ac ? cost diff is only 7-8000 -so is it justified?
2) does invertor ac hav to work continously or is it fine with my requirement?
3) for both which company - panasonic , diakin or hitachi?
4) in short 5 star or invertor- which will be cost effective?
thanking you

1.For 7-8 hours there would be no huge price diff in electricity bill between a 5 star and inverter
May be 200 -300 Rs less with inverter .Go for 5 star and save the money
2.No
3.Daikin and Hitachi.Ignore panasonic
4.Inverter becomes effective to a 5 star only when you use it for more than 10 hours per day. Otherwise the extra price is not worth it