Electricity Saving Tips For Homes And Offices

Ceiling Fan blade angle can impact electricity consumption

By on September 3, 2017

You have a few ceiling fans in your home or office, and you yourself clean them or ask your maid to clean them up regularly. You feel good when you look at nice and clean fans, but have you ever wondered if in the process you have mistakenly disturbed the fan blade angle? Recently during one of our visits at a home we found that the angles of ceiling fan blades were completely disturbed (as shown in the image below) and on asking the reason for the same, we found that the maid finds it difficult to reach to the blades to clean them, so she tries to pull them down and in the process the blades have gotten bent completely. However this was one extreme case and we know that the bent blades certainly do not look good, but does it impact electricity consumption? The answer is “Yes” and let’s see how.

How does a ceiling fan work?

Ceiling fan is a very simple assembly. It has a motor at the center that rotates the blades attached to it when it is switched on. The blades rotate at a speed and push the air down. The motion of the blade is very much like an Oar or Blade (चप्पू in hindi) used to row a boat. Like the Oar displaces water and the boat moves ahead, the blade of the ceiling fan pushes the air downwards. As any person who is expert in rowing a boat would say, the best efficiency (more movement with the least effort) is obtained when the oars are used at a specific angle. Similarly the best efficiency of a ceiling fan is obtained if the ceiling fan blade has an angle of 10-12 degrees. Now most manufacturers do take care of these factors while making a ceiling fan. But we should make sure that we do not disturb it while using it.

Like with the Oars, if the angle is less (as in it is used flat), then the effort used would be less, but there will be no movement. A flat ceiling fan blade will be like wing of an airplane that cuts through the air effortlessly, and there will be no air movement. On the other hand if the angle is large, then there will be lot of noise as well as the motor will need more electricity to more the blades through the air, just like if you hold the oar flat and try to row, the amount of effort that you will need will be larger.

Never mix the blades

Blades of different fans have different designs and they are optimized to work in a specific assembly. We have commonly seen that in the name of “Jugaad” some people may attach blade of a different fan to a different machine. Please do not do it as the blades are designed for a specific fan. This could disturb the balance of the fan and can also result in increase of electricity consumption.

So what do you need to do?

Whenever you clean the fan or get it cleaned, just make sure that the blade is not being pulled hard such that the design of the blade is disturbed. Also do make sure that the blades are of same type, size and angle so that the balance of the fan remains and it does not consume more electricity.


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अगर आप के कुछ भी सवाल हैं, वह आप नीचे दिए हुए सवाल-जवाब सेक्शन में पूछ सकते हैं। आप अपने सवाल हिंदी में भी पूछ सकते हैं और हम आपको हिंदी में ही जवाब देंगे। कृपया एक ही सवाल को बार बार ना डालें। आप एक बार जब "submit " बटन दबाएंगे, उसके बाद आपका सवाल यहाँ दिखने में थोड़ा टाइम लगेगा। कृपया धैर्य रखें। अगर हमारे पास आपके सवाल का जवाब है तो हम उसे जल्दी से जल्दी जवाब देने की कोशिश करेंगे। कृपया अपने सवाल ई मेल या सोशल मीडिया पर ना डालें।

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19 comments

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1

sir i have bought five crompton but found that the air flow is resticted at the centre only not spreading can u tell
me the reason. the height from floor to blade is 7.75 ft and ceiling to blade 1.75ft

2
Abhishek Jain (Mod)

Ideally ceiling fans should be installed at about 18 inch from the ceiling and at least 7 ft from the floor. So your installation is right. A lot also depends on the pitch of the blade (or the angle). It may be a design issue as well.

3

Does a ceiling fan consume more energy in the summer as compared to the winter, given equal running speed and time?

4
Abhishek Jain (Mod)

No it does not. It is independent of season. Electricity consumption depends on speed of the fan.

5

Great..thanks for the reply. Someone opined that temperatures affect the heating of the motor within, and energy consumption is affected.

How about its age ? Whether an old fan can consume more compared to newer? Same question for fridge and AC too...

6
Abhishek Jain (Mod)

Old appliances do consume more as compared to newer. They all derate with time. Better brands derate less. Also the impact of outside temperature is quite insignificant for ceiling fans.

7

Ceiling Fan with higher rpm can throw less air. Longer Down Rod is one solution.
Can you publish this article on your site - http://wp.me/p3dJz1-a6

8

I see 4 blade fan and 3 blade fan in the market. But air flow for both is almost same - I can't distinguish much.
Do you have any study on it - which fan gives more air? My understanding is 4 blade fan should give more air but 3 blade fan is more common.

9
Abhishek Jain (Mod)

3 blade fan is optimized for efficiency and output. 4 blade fan can generate more air flow, but then would need much more power to do so as extra blade will add to the drag.

10

Hi, I want to buy a fan.. could please suggest how does the blade matter as i see many different blades available in the market?

11
Abhishek Jain (Mod)

Hi Sasi,

The angle of the blade does matter for efficient air delivery of the ceiling fan. In fact Orient came up with PSPO ratings for fan that measures the right spread of air along with air delivery. But then not every fan company uses PSPO rating. The industry standard is air delivery of fan (which does not measure the spread of air or area of impact of fan). So blades do matter, but then I will not be able to tell which one is better in terms of fan design. If you just want to check based on air delivery and power consumption, then you may look at the list over here: https://www.bijlibachao.com/top-ten-appliances/best-ceiling-fan-khaitan-havells-usha-crompton-greaves-orient-in-india-electricity-consumption.html

12

Basic physics: If your fan’s blade angle is less than 12 degrees, it’s a waste of energy.

The very first thing you should look at with a new ceiling fan is the blade angle. If the angle is below 12 degrees, the fan will be largely decorative and will just eat energy without significant air movement.

Ideally, you want the blades to push air upward or downward. If your blades are at a low angle (meaning nearly flat), they won’t do either – instead, they’ll have much the same effect as an airplane wing. They’ll just cut through the air without pushing the air at all.

A 12-degree angle should be the minimum you purchase, and ideally you’ll buy one with a higher-degree angle. Blades with a 16-degree angle or above push a lot of air, feeling much like a box fan attached to your ceiling. That’s great for cooling off, but it might be overwhelming in some situations.

13

One of the 3 blades of my ceiling fan got bent. And if i turn on the fan it seems that it moves a lot like it is losing balance. What will i do now? Can it be fixed?

14
Abhishek Jain (Mod)

Hi Nazif,

You will have to replace the blade with a similar blade from the market. It would be better to replace all 3 for the right balance. You may get just the blades in the market if you know the model number of the fan (unless it is not too old).

15

Sir , would you like to tell me whether there is a specific sequence of blades in 3 blade-ceiling fan. Can we fix three blades randomly or there is some law. My new ceiling fan is making a little noise . Could you please suggest some reasons for this .

16
Abhishek Jain (Mod)

All blades are made the same so that they balance well. So there is no specific sequence. There may be some other reason for noise. You may have to call an electrician to check the same.

17

sr i want to know working of ceiling fan.

and which type of motor is used in ceiling fan and how can decide how much watt of ceiling fan is used for office and home plateform .specially in railway station,in relay room,in battery room etc.

18
Abhishek Jain (Mod)

ceiling fans either use induction motor or brushless DC motor. Most regular induction motor fans consume about 75 watts at peak speed. BEE 5 star rated induction motor fans consume about 50-55 watts at peak speed. And Brushless DC fans consume about 32 watts at peak speed. You can check this link for more information: https://www.bijlibachao.com/fans/review-superfan-bee-5-star-regular-fan.html

19

the fan air is regenerated to electricity and the external air is converted to electricity ispossible or not

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