Energy Saving Mode in AirConditioners

HailStonE

HailStonE

Skilled
Does Energy Saving Mode in Air Conditioners really help in actually saving money on the power cost.. I read in some place that the constant switching on & off of AC will actually consume more electricity than running it in normal mode...:S

What is the consumption of AC fan typically for a 1.5 ton Window AC. if running without compressor...

Which method is more suitable to run an AC so that the power bills are kept low....
 
constant switching on & off of AC always takes place ie compressor slows downn to a tickell every now and then...oldermodels were controled by thermostat and newer ones by digital control...
enery efficiency can be achived by proper installation, sealing room(not completely :)), tinting windows and setting and prefering higher temps than much chilling 16-20 oddd
21-23 is good for most.. and keep watch on doors as they let in fresh hot air along with loss of old cooled air

u can shave as much as 20%n of u r power bills
 
racy1 said:
Which method is more suitable to run an AC so that the power bills are kept low....
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Here're some of the tips to keep the bills low:

General Cooling Tips

Of course, the best way to reduce your air conditioning bills is to reduce heat in your home, especially during summer months. The tips below can help reduce the workload on your air conditioning solution:

* Set the temperature a little higher. Most people can be comfortable with a setting of 78-80 degrees Fahrenheit, plus you'll save 7 percent to 10 percent of your cooling costs for each degree above 78.
* When you leave home, turn off the air conditioning or set the thermostat up a few degrees.
* Be sure your filters are clean. They should be checked monthly. (Remember to check filters that may be in a unit located in the attic.) Coils of an outdoor unit should be free of debris and not blocked by plants, shrubs, etc. Be sure the return air grill inside your house is not blocked by furniture or other items. (If you have more than one return, check them all.) A return needs a free flow of air for the air conditioning to operate most efficiently.
* Keep doors and windows closed when air conditioning is on. Turn off kitchen or bathroom exhaust fans when your air conditioning is operating.
* Caulk and weather-strip leaky windows and doors.
* Use a ceiling fan or portable fan to supplement your air conditioning. A fan can make you feel three to four degrees cooler (and only costs a half-cent per hour to operate) so you can set your thermostat a few degrees higher and save on cooling costs. Use in occupied rooms since fans cool people, not rooms. As a safety precaution, turn off ceiling fans when you leave your home.
* For central air conditioning systems, keep the fan switch on your thermostat in the "auto" position when cooling. This gives you better cooling and humidity control. Having the fan switch "on" continuously could cost $25 extra a month on your electric bill.
* Use shades or drapes to block the hot sun from heating up your home. Use awnings, trees and shrubs to shade your home.
* Use your microwave or countertop appliances for cooking instead of the oven or stove.
* If you suspect your air conditioning system is not cooling properly, have it checked promptly. A unit that is having operational problems can cause extremely high bills.
* If your air conditioning equipment is older and less efficient, compensate by being extra careful about temperature settings, hours of operation and filter condition.
* Make sure your home is properly insulated. In existing homes, wall insulation may be too expensive to install, so concentrate on attic and floor insulation.
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The Difference Between "Auto" and "On"

Most central air conditioner thermostats are equipped with two fan settings – "on" and "auto." When the setting is "on," the fan runs continuously. The "auto" setting allows the fan to run only during cooling cycles (when the air conditioner compressor is operating). When the air conditioner is in use 24 hours a day, the cooling compressor only operates about 50 percent of the time, or 12 hours.

The additional fan operating time that occurs when the thermostat is set to "on" can add approximately $25* to monthly air conditioning bills. Using the "auto" setting, on the other hand, saves energy and money because the fan operates fewer hours.

In addition to achieving energy and cost savings, the "auto" setting promotes more comfort in the home by providing better humidity control. Humidity is less controlled when the "on" setting is used as moisture removed during the cooling cycle is recirculated back into the home while the compressor is off.

Some customers prefer the "on" setting because it provides continuous airflow. However, the air circulating when the compressor is not operating is not "cooled" air. This airflow into the home will actually be warmer than current room temperature if the air has circulated through ductwork located in a hot area such as an attic. Continuous air circulation is better provided by the use of a ceiling fan or circulatory fan in each occupied room.

The "auto" fan setting on central air conditioner thermostats can offer more economical air conditioning and better humidity control. The same holds true for central heating systems – the "auto" setting provides more economical operation. Progress Energy encourages consumers currently using the "on" setting to consider using "auto" to help reduce their cooling and heating costs.
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Closing Vents: Does It Save Energy?

Customers often ask, "Can I save energy by shutting off central-system air vents in unoccupied rooms of my home?" Progress Energy's experience consistently shows that this practice saves little energy and, in some cases, may actually raise operating costs.

* Avoid Operating Efficiency Reductions
By design, central air conditioning and heating systems are sized and constructed to distribute a specific quantity of air throughout a home. Consequently, closed vents may alter the amount of air moved, and disturb the balance and operation of the system. This, in turn, may result in reduced operating efficiency and increased operating costs.

* Consider Home and System Design
Unless your home and system are specially designed to maintain different temperature zones, we do not recommend closing air vents as an energy-saving practice. When the walls of a home are not properly insulated for zone cooling, energy will still flow to or from the rooms with closed vents, in addition to affecting system operation.
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from:
Air Conditioning - Progress Energy :)
 
tHeFiRsTiDioT said:
I keep my LG at 30C at night with the fan on - its very comfortable if you sleep under the fan.
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stellarhopper said:
yep...28-30'c with ceiling fan on at full speed works like a charm even in hot mumbai afternoons...
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Both of you're doing the wrong thing. :)

Guess what?!?!? :p

The ceiling fan is such an odd invention that instead of cooling the room, its heating up the air inside. You'd have very well noticed this effect when u switch on a fan during a hot noon. The warm air rises up. :)

However, in case of rooms which're well ventilated[say like a computer cabinet with an inlet and an exhaust window] the effect is not noticed and we sweat and the cooling effect thus produced is a result of perspiration.

Now when u switch on an AC + a fan, the AC produces cooling and the fan aids in heating it up. Very well u dont notice it, thats another thing cos temps're @ 29-30'C all the time. :)

Science apart, an AC @ 28'C does the best job. Low on compressor work, good effieciency all around, low on electric bills as well.
 
Agreed. I don't know the science behind it, but in practice a room is ALWAYS cooler with just the AC on than having the fan on too. (and guess what, you save electricity by having the fan off in addition).
 
depending on the hrs u will be running .. apart from proofing ur room against heat .. go and get ur self an aircon with a DC controlled Compressor.

The most important way to save money is RIGHT SIZE it .. so unless ur room is 200Sq ft+ u dont need a 1.5 ton AC ..
 
I am a bit confused.. both arguments are in favor & against the use of the ceiling fan.. My room is positioned such that it receives direct sunlight almost throughout the day. Also there is roof above the ceiling... Local climate is quite hot & anything above 24C does not cool the room...

Due to radiation the walls are hot even after sunset for quite a long time... But all this is a different aspect...

The main question is constant On/Off cycle & does it take more power than keeping the AC in cooling mode where compressor switches off when desired temp is reached while fan is still running...
 
gannu said:
Both of you're doing the wrong thing. :)

Guess what?!?!? :p

The ceiling fan is such an odd invention that instead of cooling the room, its heating up the air inside. You'd have very well noticed this effect when u switch on a fan during a hot noon. The warm air rises up. :)

However, in case of rooms which're well ventilated[say like a computer cabinet with an inlet and an exhaust window] the effect is not noticed and we sweat and the cooling effect thus produced is a result of perspiration.

Now when u switch on an AC + a fan, the AC produces cooling and the fan aids in heating it up. Very well u dont notice it, thats another thing cos temps're @ 29-30'C all the time. :)

Science apart, an AC @ 28'C does the best job. Low on compressor work, good effieciency all around, low on electric bills as well.
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Hmmm - I still didnt follow what you meant when you say that the fan heats the room up.
The warm air rises up
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This is a good thing, right? I am at the floor level, so I would like the cooler air down. The room is not ventilated and completely sealed off. There is no perspiration. How does the fan heat the room?

Now when u switch on an AC + a fan, the AC produces cooling and the fan aids in heating it up. Very well u dont notice it, thats another thing cos temps're @ 29-30'C all the time. :)
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My take - I get a blast of cold air from the fan (which otherwise would have been in the room but not moving around). In both cases the temperature would have been the same, but the air being moved around by the fan makes you feel cooler. This is why we normally have a fan in the room right?

I don't know the science behind it, but in practice a room is ALWAYS cooler with just the AC on than having the fan on too. (and guess what, you save electricity by having the fan off in addition).
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Strange but my experience is exactly the opposite, especially at these temperatures.
 
tHeFiRsTiDioT said:
Hmmm - I still didnt follow what you meant when you say that the fan heats the room up.
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Ok.. Try doing this..

While u're off to work, make sure all the windows in one of ur room is closed. Heck, just for the sake of this.. :p

Once u get back, switch on the fan and u'll notice the warm air spreading everywhere and then it'll be back to the normal once u open all the windows.

Now u very well know u're a heat producing organism and the air we breathe out is basically composed of carbon dioxide which's a greenhouse gas helping in heating the things around.

Hw abt closing all the windows again, switching the fan 'on' for sometime and being present in the room for say half an hr?? U'll be virtually boiling inside the room w/o proper vents.

In another instance, ur computer cabinet. If there were no inlet and exhaust fans and the processor HSF keeps spinning, removing the heat out, this heat obviuosly has to go out through somewhere right???

If this doesn't the warm air spread around heating everything eventually.
 
gannu said:
Ok.. Try doing this..

While u're off to work, make sure all the windows in one of ur room is closed. Heck, just for the sake of this.. :p

Once u get back, switch on the fan and u'll notice the warm air spreading everywhere and then it'll be back to the normal once u open all the windows.

Now u very well know u're a heat producing organism and the air we breathe out is basically composed of carbon dioxide which's a greenhouse gas helping in heating the things around.
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Again, you just prove my point :eek:hyeah:
Its not the fan which heats up the room - the hot air is already present, the fan just circulates it. As a corollary, if there is cool air, that too will be circulated and the effect is a lot more.

If there is a room with no ventilation and you sit in the room for half an hour, the room WILL get heated because of the heat you exude. The fan has nothing to do with it. It will only circulate the heat you exude.
 
tHeFiRsTiDioT said:
The fan has nothing to do with it. It will only circulate the heat you exude.
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And so is it heating up the air inside. :eek:hyeah:

And so running an AC with a fan is not justified. :no:

Moreover u're unnecessarily spending the bill for running the fan when the AC's on. Just make the thing swing in the right direction and it should do fine. :)
 
gannu said:
And so is it heating up the air inside. :eek:hyeah:

And so running an AC with a fan is not justified. :no:

Moreover u're unnecessarily spending the bill for running the fan when the AC's on. Just make the thing swing in the right direction and it should do fine. :)
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:bleh: Then we have to agree to disagree!
The bill for the fan is lesser than the bill for the AC being kept a few degrees higher
 
I generally use as following:

At home specially during night:
I keep temperature at 26 degrees and put the AC on Sleep mode, which is automatically raise the cut off temperature at every 1 hour.

After two hours of operation at 30 degrees AC will shutdown automatically, and if the sleep period is long then may get switched on if the need be.

Meanwhile if sometimes we feel colder, then switch off the ac and put on the ceilling fan at medium speed which suffices for the night.
At work :
As my chamber is having direct sunlight i have got my windows covered with suncontrol film, i keep the temperature at 27 degrees with full auto mode.
 
@gannu
i beg to differ...
1. ac w/o fan needs to be kept at 25 for me to feel comfy in a hot afternoon, if i switch on the fan after the ac has been on for an hour...i actually start feeling very cold and have to raise the temp to 29/30
this is from experience.

2. its true that warm air rises to the top and the fan circulates that...
but consider this.
hot air is being produced by ppl in the room and say even my comp is on.
ac is at 29 and fan is on.
the hot air being produced is constantly being sucked in by the ac and is cooled down.
my ac vents are directed upwards, and all the cold air is thrown down by the fan.
the hot air produced by ppl etc is smply not enuf to overwhelm the cooling effect of ac.

3.the extra cooling by the fan is produced as follows.
if only ac is on, the air in the room is more or less still.
suppose we are present in the room.
our body is continuously giving out heat into the surroundings.
so the envelope of air immediately around us becomes warm and creates a sort of insulation between us and cool air in the room.
the only reaso we dont start sweating is that this warm envelope is also weakened due to convection currents which make the warm air go up.
but this is a very slow process, and convection rate is directly proportional to temperature difference.
so decreasing the temp of the ac further will accentuate this process.

now consider the case when fan is on.
the fan circulates the air in the room very well. the turbulent flow churns up the air and tends to have an averaging effect on the temperatures.
this dissipates the "warm envelope" around us in the earlier case, and the air in immediate contact with us is at avt temp as opposed to higher-than-avg temp.

remember when we were kids and had studied abt experiments including heating water and taking temp readings....they always told us to stir continuously....to keep the same temp throughout...
4. even disregarding all thories.....
i personally feel much more comfortable with ceil-fan on.
 
^^^ Holly Molly... Both you guys really got me confused... To go with the fan or not... that is the question :rofl: :rofl:

But does the fan inside the AC has a power rating that we know about...

I think switching on the ceiling fan will negate the benefit of Energy Saver Mode.. But then the AC is switching off & temp. is set low while the ceiling fan is working to cool you off...

My point is does the starting & shutting of compressor so much will actually consume more electricity than using it without fan (ceiling i.e. ;) )
 
compressor will turn on and off in all modes at all temps...
its jus that at say 22'c on time of compressor will be more and off time less,
opposite at say 30'c...
these cycles are not gona harm the compressor or anything...
as far as electricty consumption is concerned, higher the temp, lower the elec consumed...
i dont know what exactly does the 'energy saver mode' do in ur ac...but most probably its a marketing gimmick...

i didnt understand what u said abt power rating of fan inside ac...
 
racy1 said:
^^^ Holly Molly... Both you guys really got me confused... To go with the fan or not... that is the question :rofl: :rofl:
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The simple solution is to test it for yourself. Different people have different preferences. Many old people for instance feel that coolers cool much better than ACs. I somewhat agree with it, in the sense that a good sized cooler can cool 3-4 rooms easily. But the quality of cooling one gets with an AC is much better. (again, some people don't like it because it is dry air).

So fan or not.. try it yourself. I think that when you enter a hot room initially and turn on the AC the fan helps (because of the cooling effect of drying your perspiration IMHO). But in the long term ( >20 minutes) it makes thing worse for sure. Then it's better to have it off.

Also depends on your AC positioning. In one room I saw the AC was blowing out cool air right into the ceiling fan. So if the fan was off, great. But when you turned it on, the cool air was being redirected towards the walls, and totally destroyed the cooling effect.
 
stellarhopper said:
i dont know what exactly does the 'energy saver mode' do in ur ac...but most probably its a marketing gimmick...
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I also suspect the same after reading this

"Multi-speed motors achieve their lower speeds by a crude de-optimization of the magnetic induction angles by selecting different phasing. Usually the slowest tap is 25% less efficient than full power."
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So running at lower speeds is not designed to save energy but just to give you less cooling.

Fixed speed ie conventional compressors give the best efficiency *only* when run at full load.
 
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