[Arun_S]

Originally Posted by condor

For folks who use A/c at home: A suggestion that I came across from a person who I find is very logical.

Instead of using the A/c at 18 -20C, set the temp to 26-28C - And use the fan at same time. He says it can help achieve sufficient cooling while reducing electricity bills.

Does any one want to try it out and share your experience ?

I have been running this setup only for all these years, A/C at 26-28C and fan speed at 2/3.

These are some of my observations

• Repeatedly get complaints from A/C Mechanic there is too much dust accumulated in machine as I am using fan
• My daughter has Asthma, her pediatrician suggested not use this combination as it will trigger allergies more.

Tried just the A/C alone, found it difficult to sleep. Back to the old ways.

[Maverick Avi]

Originally Posted by Arun_S

[*]My daughter has Asthma, her pediatrician suggested not use this combination as it will trigger allergies more.[/list]
Tried just the A/C alone, found it difficult to sleep. Back to the old ways.

A/Cs now are coming with PM2.5 filter. I think if you can close the room completely and let A/C run for sometime then the dust problem can get solved to an extent and help your daughter.

[Arun_S]

Originally Posted by Maverick Avi

A/Cs now are coming with PM2.5 filter. I think if you can close the room completely and let A/C run for sometime then the dust problem can get solved to an extent and help your daughter.

Thanks for your suggestion, will definitely consider it during my next purchase

[saion666]

Has anyone installed a vrv system in their home.
Got a new 3bhk and the design is such that the AC outdoor units will have to be placed at a single ledge outside the balcony.

I do not want multiple outdoor units blocking the balcony so was thinking of a multi split or a vrv system. However i could not find any information related to the pricing and availability. Requirement is for 4 indoor units.

[sandeepmohan]

Originally Posted by condor

Does any one want to try it out and share your experience ?

26 to 28 degrees, depending on where you are, will be next to no cooling or very limited cooling. There is no way I can sleep with the temperature set so high. My comfort zone is at the 23 to 24 degree mark. I usually start the unit at 22 degree and let the Sleep mode do a creep of the temperature gradually over night.

The technician is right, you will save power. 18-20 degrees is definitely outside the comfort zone of the human body and you will start to feel cold, will need a blanket or quilt. Your AC will be working over time too. At the higher end of the technician recommended temperature setting, you will be sweating and there will be next to no comfort sleeping in a closed room.

Originally Posted by Arun_S

My daughter has Asthma, her pediatrician suggested not use this combination as it will trigger allergies more.

More than an AC, you need an air purifier. Your Pediatrician is correct. Avoid air conditioning as much as possible for your daughter. Alternatively, you can cool the room before she goes to bed and then switch off the aircon. A closed room does not work for anyone suffering from respiratory problems.

[m8002?]

Originally Posted by saion666

Has anyone installed a vrv system in their home.
Got a new 3bhk and the design is such that the AC outdoor units will have to be placed at a single ledge outside the balcony.

I do not want multiple outdoor units blocking the balcony so was thinking of a multi split or a vrv system. However i could not find any information related to the pricing and availability. Requirement is for 4 indoor units.

I am in the same boat, but for an independent house in Chennai. Based on the initial investigations, it would the around 50% costlier than individual units though the long term running costs would be lower.

Another risk is that if the system breaksdown, then you are without AC for the entire house.

I have still not finalized either way since I am not moving in to the new house immediately.

[sagarpadaki]

The Split AC in our home is cuts of compressor beyond the set temperature. Say, I set 28 degrees. It cools the room till 25 degrees and then compressor cuts off. Is this variation normal ? If not, how to correct it.

I recorded this temperature form a digital as well as analog thermometer. Both of them registered 25 degrees when the compressor cut off.

[civic-sense]

Originally Posted by sagarpadaki

The Split AC in our home is cuts of compressor beyond the set temperature. Say, I set 28 degrees. It cools the room till 25 degrees and then compressor cuts off. Is this variation normal ? If not, how to correct it.

I recorded this temperature form a digital as well as analog thermometer. Both of them registered 25 degrees when the compressor cut off.

My AC behaves similar, but in auto mode only. But I don't understand why it keeps cooling beyond the set temp of 28 and on to 25 before cutting off the compressor. Shouldn't it do it at 28?

[ABHI_1512]

Originally Posted by condor

For folks who use A/c at home: A suggestion that I came across from a person who I find is very logical.

Instead of using the A/c at 18 -20C, set the temp to 26-28C - And use the fan at same time. He says it can help achieve sufficient cooling while reducing electricity bills.

Does any one want to try it out and share your experience ?

My take is little different and it’s working great since the window AC days. It’s basically a two-stage program and works like this-

1. Set the thermostat of the AC at 22 degrees and use the fan at full blast for around 15-30 minutes. If you want the room to cool even faster then using the TURBO function is advisable.

2. As soon as the room cools and/or after 15-30 minutes- whichever occurs earlier, set the thermostat at 24 degrees and switch off the fan and then one can set the timer according to the sleep cycle.

The room remains cool enough for the night and is very comfortable without being power consuming to boot. If the AC has a sleep function then it’s even better since after 24 degrees, it creeps upto two notches after two hours and gives a comfortable eight hour sleep cycle.

There is a school of thought that says that operating both AC and fan at the same time actually puts both the appliances under pressure, not something that is not debatable though. I have been practising the above process for long and saving on bills much before the star ratings came into vogue.

[Crow]

I may be an outlier here but our AC chills the room even when we set the temperature at 27 in Mumbai. Maybe I just feel too cold because we’ve not been stepping out at all.

We got a Mitsubishi 5-star inverter AC after recommendations from this thread, and it’s working great. I’ve banned everyone from using the AC+fan combo. Only one of the two runs at any time and it’s been fine.

[Thad E Ginathom]

Originally Posted by Crow

I may be an outlier here but our AC chills the room even when we set the temperature at 27 in Mumbai...

One thing here is that an AC on 28 may not be cooling the room much, but it is drying it. Lower humidity leads to feeling cooler.

[Prowler]

Originally Posted by sagarpadaki

The Split AC in our home is cuts of compressor beyond the set temperature. Say, I set 28 degrees. It cools the room till 25 degrees and then compressor cuts off. Is this variation normal ? If not, how to correct it.

Originally Posted by civic-sense

But I don't understand why it keeps cooling beyond the set temp of 28 and on to 25 before cutting off the compressor. Shouldn't it do it at 28?

It is due to a phenomenon called as thermal hysteresis. The thermostat in the ac/fridge always has a lag when controlling the compressor. If you set it at 28, the compressor will try to cool the room at a lower temperature than the set one and will start after the temperature reaches a set point. It is normal. With earlier mechanical thermostat it was a physical property which can't be changed. But with current electronic thermostat the hysteresis is part of the control algorithm of the CPU in the control board.
Hysteresis prevents frequent turning on/off cycle to protect the compressor. With inverter ACs, the hysteresis is lower than with conventional AC.

[sagarpadaki]

Originally Posted by Prowler

It is due to a phenomenon called as thermal hysteresis. The thermostat in the ac/fridge always has a lag when controlling the compressor. If you set it at 28, the compressor will try to cool the room at a lower temperature than the set one and will start after the temperature reaches a set point. It is normal. With earlier mechanical thermostat it was a physical property which can't be changed. But with current electronic thermostat the hysteresis is part of the control algorithm of the CPU in the control board.
Hysteresis prevents frequent turning on/off cycle to protect the compressor. With inverter ACs, the hysteresis is lower than with conventional AC.

I though the temperature sensor is faulty. What you say makes sense. If the compressor cuts off once the set temperature is reached, then it has to turn on immediately if the set temperature exceeds leading to frequent switching on/off of the compressor.

[Maverick Avi]

Originally Posted by sandeepmohan

More than an AC, you need an air purifier. Your Pediatrician is correct. Avoid air conditioning as much as possible for your daughter. Alternatively, you can cool the room before she goes to bed and then switch off the aircon. A closed room does not work for anyone suffering from respiratory problems.

Air purifiers are only designed to work in closed spaces. And if someone intends to use one then I don't see them being effective other than in a closed room. People with respiratory problems might actually benefit from a close room(depending on condition) but yes air conditioning might not be a good idea due to its dehumidifying nature.

[mvadg]

Originally Posted by mvadg

I do this all the time. Works great!

This year, I've already started using my AC in Bangalore. After I posted my experience (from the previous years), I have been observing more carefully and I have to agree with everyone - using the fan tends to aggravate the effects of the already low humidity (very rare in Bengaluru). I also think dust from the AC filters is likely to be blown around by the fan.

Time to clean the indoor unit and see if I can replace the filters. I am also going to try programming my good old Sony remote to slow down the fan (Superfan with remote) after the initial few hours. One advantage of the fan, I noticed, is that it circulates the cold air better. So AC plus low speed fan may work well (again, this will depend on local conditions), a low speed draft does feel cooler.