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Sunday, May 19, 2013

Advantages of installing Ceiling Fans



Why we had a ceiling fan in the Bed room.

Room ventilation generated by ceiling fans can make the ambiance feel cooler by a few degrees. This is something standing and wall fans are not designed to achieve.
When applied intelligently together with air-conditioning, it can help to save electricity consumption. This was how I convinced my wife the savings without doing a laboratory test:
When using the air con with ceiling fan, this 2 additional steps were applied:
1.   Set the thermostat on the aircon to 3 to 5 DegC above the preferred ambiance temperature. For example, if you are used to sleeping at 20DegC, set the aircon thermostat to 25DegC.
2.   Set the auto off-timer on the aircon to 3 hours before your wake up time. For example, if user sleeps at 10pm and wakes up at 6am. Set the aircon auto off-timer to 3am.


Thermostat set on air con
Air con Operating hrs
Fan operating hrs
Energy consumption per month (KWhr)
Estimated cost savings (April 2013 SP rates 26.7c/kWhr)
Aircon (2.5KW) only
20DegC
8hrs
0hrs
2.5KWx8hrsx30days= 600KWhr
S$ 160
Aircon (2.4W)+ ceiling fan (0.08W)
25DegC
5hrs
8hrs
2.4KWx5hrsx30days
+ 0.08KWx8hrsx30days
= 380KWhr
S$ 102





S$ 58 per month per room
Assumptions:

(A) Assume 0.1kM savings from thermostat temperature difference of 5DegC.
(B) Typical 1 air con blower from a system operating at 8,540BTU/hr = 2.5kW
(C) Typical ceiling fan power consumption = 60W to 90W (costing about S$300 to purchase)
(D) Estimated electrical consumption = Input (kW) X No. of hours used X No. of days per month X Current Utility Rate

The choice seems clear! Conservatively, even if the real difference is only half of the calculated, the electrical tariff savings will pay for the ceiling fans in 10 months! The only exception I can think of is if users cannot sleep in a “windy” environment due to arthritis.

Disclaimer: We are not trained electrical engineers. The above is a heartlander trying to make sense of the small things in life. Apply at your own risk! If there are any experts out there who can correct or verify this, please leave a kind comment.

Also see
Choosing air-conditioner (coming soon)
Installing Ceiling Fan (coming soon)
Cost savings from using LED lights (coming soon)
Lighting-concept-cost-savings

5 comments:

  1. Hi! Interesting. Thankyou. Your post is for bedroom (ac timer off 3 hrs before wake up). How about calculations for Living Room? Your views on ac for kitchen?

    ps: I'm new Renotalk forummer, no posts there yet.

    ReplyDelete
    Replies
    1. Hi fragrantflowers,

      Thank you for your comments.

      We installed a ceiling fan in the living room and it is usually switched on when someone is there. Thus, the living room aircon is only used on special occasions when there are some guest or on an exceptionally warm day.

      The kitchen is designed for heavy duty stir-frying and baking and is can be isolated from the living room. It made no sense for an ac in the kitchen for us. Also note that the dinning table is in the living room.
      See http://hdbrenovation2009.blogspot.sg/2012/05/kitchen-design-concepts-and-specifics.html

      In my humble opinion, the functional circumstances I can think of installing an ac in the kitchen are:
      1. for the comfort of diners if the dining table is in kitchen
      2. do not cook, but kitchen has other functions eg study corner for children.

      Delete
  2. There are, indeed, great benefits in having ceiling fans. They have the ability to cool and even the temperature in the room. And as they are designed to circulate the air around, it also helps make the air you breathe safer and cleaner. Just make sure, however, that they are properly installed lest you want them to fall down on you and cause accidents.
    Keith @ HandyPro

    ReplyDelete
  3. hi. i recently just installed acorn ceiling fan (VENTILATEUR 238NL 42"/52" WH) in the bedroom, and it doesn't produce wind even at high speed, before i check with the contractor, just wanna ask if you have encounter this problem? any idea how to fix it? is it due to the direction of the blades? thanks!

    ReplyDelete
  4. Very interesting blog. Alot of blogs I see these days don't really provide anything that I'm interested in, but I'm most definately interested in this one. Just thought that I would post and let you know.
    מאווררי תקרה

    ReplyDelete