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Reduce Pollution by Using Ceiling Fans

The 500lb Gorilla in the room

Are you totally frustrated with the Hong Kong Government’s lack of action on air pollution? Do you think they should be moving faster and taking action now? Do you think they and big business are really doing all they can to reduce energy consumption to reduce the major cause of air pollution in Hong Kong, namely, local power companies burning coal. Do you attribute and put all the blame for pollution on the Hong Kong Government and big business?

Now ask your self this: Have you done all you can to reduce your own electricity consumption (see following
questions)? If the answer is no, then you are part of the pollution problem in Hong Kong.

  1. What percentage of lamps in your home are energy saving Compact Fluorescent Lamps (CFL)? (100/75/50/25/0 %)
  2. How much energy (watts) does a typical CFL consume? (200/100/50/20/10 watts)
  3. How many of your rooms have aircon units (split, wall etc)? (All/most/some/none)
  4. How much energy does a typical aircon unit consume? (50/100/300/2000 watts)
  5. At what room temperature do you normally set your aircon to? (20/22/25.5/27/30 DegC)
  6. Do you switch the aircon off every time you leave a room? (Always/most/some/never)
  7. What amount of time is your aircon on but no one is in the room? (100/75/50/25/0 %)
  8. How many of your rooms have you fitted ceiling fans? (All/most/some/none)

Some replies

A typical CFL in a room will rated at about 15 watts and this is equivalent to 80 watts for an inefficient incandescent lamp – therefore an excellent incentive to replace incandescents and save energy.

However, a typical aircon unit in a room when running can consume over 1500 watts – 100 times more energy than the Compact Fluorescent Lamp. Hence the aircon unit is the 500lb gorilla in the room that nobody is talking about.

Hint: Leaving an aircon running for 1 hour with no one in the room is equivalent to leaving the light on continuously for 4 days.

It puts things slightly in perspective doesn’t it!

The Problem

In the heat of summer we all need the aircon on – it is almost impossible to live comfortably without it. The question therefore is: how can we avoid or reduce this huge source of energy consumption?

The Potential Answer?

Studies (Florida)* have shown that using ceiling fans can potentially result in electricity savings of 14% per annum
for 1 DegC (approx) increase in the aircon thermostat setting and still provide good comfort levels.


Ceiling Fan Energy Savings

However, there is a catch (isn’t there always). The studys’ conclusion finds that the overall results, as far as energy
savings are concerned, are mixed. This was due to 2 main factors;

a. ceiling fans and aircon left running in unoccupied rooms
b. aircon setpoint not adjusted upwards.

The Possible Solution?

The Florida study also concludes that future work was required and hence the, ‘Spanking the 500lb Gorilla’ Project was
born. The objective of this project is to prove the hypothesis that a typical Hong Kong home’s electricity bill could be reduced by up to 30% with a payback target of approximately two years by using ceiling fans and a Smart Thermostat Controller system.

The Project in Action

Until recently, trying to do this has been expensive and complicated. The following shows the present setup and how
this can be achieved with minimum expense and simplicity using a presence detecting temperature control system.

Smart Thermostat Controller

  • room presence detection – PIR*
  • on/off and 3 speed control for wall panel type ceiling fans
  • on/off aircon control
  • tamper proof set points
  • auto or manual control and or timer controllable
  • standalone +/or network to Smart Metering

*PIR = Passive Infra Red Presence Detector Smart Thermostat system courtesy

Smart Thermostat Controller

The first system was installed mid April07 and to date (01Jul07) three rooms have now been completed. And so it was
with bated breath that the arrival of the power utilities bimonthly bill for May and June07 was anticipated (go figure).
The following shows the results so far ..

Power Utilities Bimonthly Bill

We can see that even with an uncompleted system, the energy savings are quite remarkable and on track for the
target of 30% reduction in overall electrical consumption.

And this has been achieved with no loss of comfort. In fact, the impression and feedback from family members has
been that the reduction in the use of aircon has made for a fresher, more healthy living environment.

The implications of this on Hong Kong’s present pollution (and energy policy) will be profound if many more people
install these systems.

It is beholden of each of us at Clear The Air and other activists to lead the way and to show that the power of change does not lie with government but with the people and that by maximizing our potential to save energy we can all have a direct
effect on the environment.

Mark Hunter MSc

Chair – Energy Committee, Clear The Air.

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