Recommend an inverter based AC (some prices inside)

[avidyarthy]

As suggested earlier, get the reflective paint job done first. All said and done, it shan't go waste as the cooling load on 'any' AC would 'definitely' come down. See whether the existing 1.5 TR is cooling better after the paint job. If it does, then fine, you can settle for a new 1.5 TR inverter AC. Your room size, 'that too on the top floor' is on the borderline to easily commit an error of judgement!

For nights its fine, but day operations are way too away for comfort.

 

[naveenjn]

I am intending to use the AC from 3 PM to 1 AM daily. Also I just need the temperature to be in 27C range, nothing less. I am hoping 1.5T will be enough for these needs.

Roof painting will be done but it looks like I will have to paint the whole roof as it will look odd with a portion being in white color and the rest of it red (currently the whole roof is red).

An interesting thing I learnt from the manual posted on the last page is that this Sharp inverter AC actually displays in real time, the tonnage that is being used to currently cool the room. Coming from a 3 star 1.5T AC, those low values should be a treat to the eyes

 

[Thad E Ginathom]

Manuals are a much better way of learning about a product than sales brochures. There is a much higher chance of what they say being true!

 

[avidyarthy]

The power bills at the end of the month tells the real story! .... not the bells & whistles.

 

[Thad E Ginathom]

Yes that's true, and even with a fairly basic split AC I still only use about a third of the remote buttons.

There are some modern features available I do not want! Magic eyes that follow you around the room so they can blow the air your way. Clever idea, except for those of us that want to cool the room, not sit in a draft.

Largely as the result of following the relevant thread on Team-BHP, my next AC purchase will probably be Daikin. However, whilst the ongoing collective wisdom of the thread suggests that Daikin and General are the Rolls and the Bentley of the industry, newcomers Sharp and Panasonic have created a lot of interest.

 

[Demon]

@naveenjn

Please also take in to consideration the Ambient temperature the machine is designed to work in.

If you look into the specifications there will be a value against "Maximum permissible outside temperature / ambient temperature" which plays a very important role in how the machine functions in very hot days.

In case of inverter AC, I could see only Panasonic tropical inverter has a value of 55 against it. All the Daikin range falls in the 46 deg category. Even Ogeneral's inverter falls in the 46 deg category, only their 1.5 and above non-inverter models have the value as 52.

We have OG 1.5 ton in my brothers room which is close to 160 sq ft and a 1 ton OG in the next room which is exactly 100 sq ft, both with open terrace and one west facing wall. During hot days I used to wonder why the one in the smaller room is not cooling that effectively as the one in the next room and found the answer much later when I was casually looking into the manuals. Only 1.5 ton and above models are designed to work in ambient temperatures around 52 deg c, 1 ton can work effectively till 46 deg c.

I feel bad that I didn't look into this when I went for a Daikin inverter for my moms room, if I had, I would have stuck to OG 1.5 ton non-inverter (but would have got from someone who can give me better service, which is a different story altogether).

I am not sure how hot Trivandrum will be during summer, but if its anywhere near Chennai, get one which can handle the heat.

What I have stated is my observation, based on the machines that are installed in my home.

If anyone else has a better understanding of this please share your views.

 

[naveenjn]

That's valuable info, Demon. I have been using my present Whirlpool 1.5T 3 star AC for 5 years now and almost daily. I normally come into the room at around 3 PM and switch on the unit, which will show the room temperature at that moment. In the past 5 years, I have never seen it go beyond 36 C.

I checked everywhere for the spec you mentioned but couldn't find the values for this model from Sharp. I am hoping all inverter ACs are comfortable at under 40 C.

 

[Thad E Ginathom]

All our three Samsungs, 1, 1.5, 2.0 ton, cool their respective rooms effectively. Definitely the midfi of ACs, although their only problem has been long term reliability. They cost us a few thousand each every year.

This last was a truly terrible summer for Chennai, with 40-plus every day for two months or more, but our record is either 43 or 46 (I forget) and I don't think we would ever see 50 here.

naveenjn will be getting soaked when we are baking: the SW monsoon prevents Kerala ever getting as hot as Tamil Nadu.

I have noticed, though, some of the manufacturers claiming tropical specifications and being effective up into the fifties. It's something to think about.

 

[avidyarthy]

It is NOT the ambient temperature 'only' that the AC handles, at places like Kolkata, Chennai and Mumbai. More than the temperature, the AC takes care of or eliminates humidity (water from the air).

In a place like Delhi, if air temperature is 40 and RH (relative humidity) is 40% and similarly, the same temperature is in Chennai, but the RH is at 80% ... then the Chennai AC has to either work twice harder or the Chennai room is to be provided with a higher capacity AC. This humidity factor is known as 'latent heat' and pure dry temperature is known as 'sensible heat'. It is faaaar tougher and costlier to remove latent heat than sensible heat.

So, if Trivandrum has sweaty weather during summers and temps touch 40 with a glaring sun .... then, watch it!

 

[agodhwani]

It is NOT the ambient temperature 'only' that the AC handles, at places like Kolkata, Chennai and Mumbai. More than the temperature, the AC takes care of or eliminates humidity (water from the air).

In a place like Delhi, if air temperature is 40 and RH (relative humidity) is 40% and similarly, the same temperature is in Chennai, but the RH is at 80% ... then the Chennai AC has to either work twice harder or the Chennai room is to be provided with a higher capacity AC. This humidity factor is known as 'latent heat' and pure dry temperature is known as 'sensible heat'. It is faaaar tougher and costlier to remove latent heat than sensible heat.

So, if Trivandrum has sweaty weather during summers and temps touch 40 with a glaring sun .... then, watch it!

I think it's the other way round, a/c perform better in humid climate than less humid climate. That's the reason earlier there were water coolers and not a/c in many states as a/c couldn't perform well. But with time the a/c got refined and perform better in low humidity as well.

 

[Audiodoc]

The question about temperature and humidity is that at the same temperature a person feels much more comfortable when the humidity is low. So a temperature of 30 degrees Celsius with 30 percent humidity will feel much more comfortable than the same temperature at 95 percent humidity.

The desert cooler cools the air inside it by the evaporation of water on the grills surrounding it. At high humidity levels the evaporation decreases substantially hence the failure to cool the air.

The ac also uses the same Newtonian principle of evaporation causes cooling however it is not the water that evaporates by the refrigerant gas inside the coils of the indoor unit. These cooled coils precipitate water just like a chilled glass of water precipitates the water on its outer surface. This collects in the indoor unit and is sent outside the room through the attached hose. So to achieve the same temperature the ac has to do more work. Converting the water in the air to liquid water and cooling the room.

So both of the above posts are partially correct but don't present the complete picture of cooling.

 

[Thad E Ginathom]

Hot air can hold more moisture than cold air. Cool the air, it looses moisture. Is that any harder work than cooling dry air?

Maybe wet air has more mass, therefore it does take more cooling. I admit that physics is not one of my strong points.

But one thing is surely true: it is the humidity that makes the climate of this part of India unpopular, even with other Indians. For me, it is indeed the prime reason for AC, especially at night.

 

[avidyarthy]

Hot air can hold more moisture than cold air. Cool the air, it looses moisture. Is that any harder work than cooling dry air?

Yes, hot air can and WILL hold more moisture, IF and only IF moisture is present. In Delhi, there is hardly any moisture during a large part of the year. Temps go above 45-46 and RH drops to as low as 5 to 15% during May-June.

Chennai has a sea next door. As temps go up, more water is held in the air. To evaporate 1 kg of water you require 540 Kcal of heat. The reverse is also true. So .............. do I need to elucidate now?

Now, something different ...
Most ACs get a bit ineffective during peak summers ... why? Bcoz, the ambient air (outside the cooled room) temperature, if at 45 deg C or higher, has come greviously close to the heat that is being rejected from behind the AC (consider standing behind an operating window AC). Since a minimum delta T or temperature difference between the two different air streams is not present, heat transfer DOES NOT (or gets very less) take place. Heat rejection has to happen someplace, right? To cater to this climatic outrage, 'only some' suppliers try and provide increased air flow and fin area in the condenser (outdoor) section. That partly solves the issue.

It goes a long way to install the condenser section in a well shaded place. Thats ought to be cooler than the open areas ... so, better heat rejection possible. ENUF classroom lectures now .... I am outta here!

 

[cmsajith]

It goes a long way to install the condenser section in a well shaded place. Thats ought to be cooler than the open areas ... so, better heat rejection possible.

I was about to ask the possibility of installing below some shade or put a shade on top of the outdoor unit so that the surrounding air is cooler. I had installed one below a shade from the top outside wall eventhough I could install at the terrace, the installer was a bit hesitant to install it there and another one with a separate shade on the terrace (with a gap of 1 ft).

 

[Thad E Ginathom]

Chennai has a sea next door. As temps go up, more water is held in the air. To evaporate 1 kg of water you require 540 Kcal of heat. The reverse is also true. So .............. do I need to elucidate now?

Latent heat of evaporation. It takes energy to change the state of a substance. Brain-cell Bingo! I remembered something from physics class hyeah:

Thanks! Sorry to be so dim. I got there in the end.

 

[naveenjn]

So I bought Sharp 1.5T AH-XP18MV Inverter AC on Monday. Cost Rs. 43000 + 1000 for installation. I originally wanted to paint my roof with heat reflective paint first but my father, who is abroad, was adamant that the painting should be done in his presence. Since I didn't want to wait for a few months I went ahead and bought the AC hoping it would be enough for the room. Fortunately it was. Here is my review.

First of all I can totally understand why Sharp recommends this 1.5T model for rooms up to 290 sqft, which normally requires 2T. My room is 240 sqft on top floor and the day it was installed was particularly hot. I switched on the unit and set the temp to 27 degrees. As you know the indoor unit displays the real time KW (i.e. tonnage). The AC always starts at 0.1KW and in 30 seconds the compressor turns on and the number starts to increase. On that hot day the number actually went up to 2.1KW! That means this 1.5T AC operated at 2.1T for a short amount of time. Once the room started to cool, the value came down and within 1.5 hours it was running at 0.5KW. I kept the AC on for about another 8 more hours (till 12 AM) and the unit was running mostly at 0.3KW. By night it was at 0.1KW and the room was still cool. That is amazing!

The next day weather felt like one of those typical conditions that mostly defines Kerala - not too hot, not too cold. I started the AC at 2 PM and it went on to 1.2KW. Within an hour it reached 0.5W and then 0.3W. By around 7PM it was at 0.2KW and by 10PM at 0.1KW. I read in the manual that the display shows 0.1KW even if it consumes lower than that.

And to verify the displayed values, I checked the energy meter as well. Previously with my old 3 star split which I use from 3.30 PM to 6.30 PM and 9.30 PM to 12:30 PM (total 6 hours), my daily consumption was around 23 units (including a 24 hour on PC and all). Now with this new AC which I use continuously from 2 PM to 1 AM (11 hours), my consumption has come down to 17-18 units, which is seriously amazing.

Indoor Unit
This is NOT one of those cute looking indoor units from LG and Samsung. It has a more manly look (like Chevrolet Beat car). It's air vent has a peculiar design. Normally the air vent has the hinge at the bottom edge and opens down (like a harmonium box). In this one the hinge is at about 1/3rd from the top and it opens to the top as well, meaning you will get an obstructed stream of air if you are standing in front of it. But the magic feature is the Gentle mode on the remote. When you press this, the vent actually rotates 360 degrees and focuses the air stream to the ceiling. So if you have the ceiling fan on, you will get cold air from it and it circulates throughout the room pretty fast. The display which shows the real time power consumption is nice and I am sure most people who buy inverter acs actually do that to save electricity bills. So putting that info straight on display is a nice idea.

Outdoor Unit
It uses the new R410A refrigerant and not sure if it is because of that but this unit is incredibly silent even when the AC was running at 2.1T. It has an all aluminum interior which is supposed to be more durable and better at heat exchanging compared to copper-aluminum mix that is used in other outdoor units.

Ioniser
The indoor unit has Sharp's famous plasmacluster ioniser built in. I tried the AC first day without ioniser and second day with the ioniser to see if there is any noticeable difference in power consumption and the good news is I couldn't find any. Sharp sells ioniser units alone for Rs 20,000 and those are rated at 15W, so I guess that is the maximum it will draw. Moreover the ioniser doesn't need the compressor to work, it works even in Fan mode.

As for the ioniser itself, I didn't notice any so called "nature like freshness" due to positive negative ions and all but one thing I can say for sure is it removes odour as it claims. With my old AC there was always some odour in the room (due to something in the room and not AC itself). With this one, the odour gets removed in 15 minutes and the rest of the time it feels fresh.

Remote Control
This is one area Sharp could improve. The remote is not really user friendly. Some buttons don't have textual labels, just some Egyptian hieroglyphics like images which could confuse some. Also there are no generic up and down buttons. So if you set the off timer at 6.5 hours and now you want to make it 6 hours, you got to plus all the way till 12 hours and then to 6. The remote's display turns off when you turn off the indoor unit, unlike my Whirlpool remote which stays on all the time.

Things I don't like
No room temperature info either on indoor unit or remote
Remote's display isn't backlit (my Whirlpool turned on green backlight when the ON button is pressed for a few seconds) which makes it difficult to use at night.

That's it then. Overall I love it. The room is cool at 27 degrees and I hope the electricity bill will be substantially low this time, despite longer period of usage.

 

[rbalagopalan]

Hi Naveen,

You have taken a very sensible decision and you are reaping the benefits. In fact I had converted almost not less than 50 buyers to go in for Inverter grade A/Cs than conventional ones.

R. Balagopalan

 

[heloanand]

So I bought Sharp 1.5T AH-XP18MV Inverter AC on Monday. Cost Rs. 43000 + 1000 for installation.
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Hi Naveen, I am looking to buy one one of these, can you tell me which shop you buy it from, also i can see previously you mentioned that @ your house you have voltage problems, so you are using a stabilizer for your split, are you using any stabilizer with the sharp inverter ac, if yes which model and price, thanks
Anand

 

[naveenjn]

Hi Naveen, I am looking to buy one one of these, can you tell me which shop you buy it from, also i can see previously you mentioned that @ your house you have voltage problems, so you are using a stabilizer for your split, are you using any stabilizer with the sharp inverter ac, if yes which model and price, thanks
Anand

I bought it from a shop called United Radio & Electricals at M G Road, Trivandrum, Kerala. I had the stabilizer from my previous Whirlpool AC which I am using with this Sharp Inverter model. The stabilizer is V Guard VWR 400 which has a voltage range of 135v to 260v and supports up to 1.5T ACs. There could be newer models available today.

 

[heloanand]

Do you remember how much they quoted for 1ton? The prices i quoted is
Panasonic- 38900
Sharp-36900
Both includes widerange stabilizer and installation
Tossing up between these two, panasonic has lot more features than sharp, but sharp got lots of recommendation on this forum
Cheers