Fans can save money when used with air conditioners

PUBLISHED : Friday, 27 June, 2014, 12:03am
UPDATED : Friday, 27 June, 2014, 12:03am

Since Shakespeare's eunuchs fanned a reclining Cleopatra, there's been something sexy about the movement of hot air.

Air conditioning serves a purpose, but it's hardly exciting. Fans, however, have come of age. The "love them or hate them" design debate seems firmly skewed to the former, as new styles and technology have earned fans a place in the swankiest properties where they are no longer camouflaged.

It was designers' demands for ceiling fans that led American producer Big Ass Fans to introduce a domestic range. The firm started out making fans for factories and warehouses but, as mechanisms were developed that made the fans quieter, architects started wanting them for their hospitality and residential projects.

The main breakthrough in fan production has been the advent of the DC (direct current) motor, which has a higher torque than the earlier alternating current (AC) motor enabling greater efficiency.

"Once the fan reaches a desired speed, a magnetic drive keeps it circulating with very little energy," says Jennifer McBride, proprietor of Life's a Breeze, a fan speciality store in Ap Lei Chau. It's also lighter and whisper quiet.

Big Ass tweaked this technology even further, obtaining worldwide patents for its Haiku line of residential fans.

"Designers like the fact that fans are very energy-efficient, reducing or even eliminating the need for refrigerated cooling," says David Williams, managing director, Big Ass Fans Hong Kong.

He estimates that during a typical summer in Hong Kong, a Haiku ceiling fan would use only HK$55 worth of electricity, based on 114.5 days of continuous, 24-hour operation.

Today's fans also look cool, made from materials such as bamboo, wicker, banana leaf, solid wood, stainless steel, New Zealand plywood or various composites, lending themselves to design interpretation

"People spend a lot of time doing interior decorating but they forget about the big blank canvas that we call the ceiling," Williams says.

Fans alone don't actually reduce a room's temperature but studies suggest they make the occupants feel cooler, by up to five degrees Celsius. The formula behind this is based on the room's size and the number of bodies in it (people and pets).

McBride says that while you would still need air conditioning at the height of a Hong Kong summer, fans used in tandem with conditioners can help save money.

"Turn your air conditioning on [at about 25 degrees] with your ceiling fan for about 10 minutes. The fan will help to circulate the cool air," she says.

"When the room is at the desired temperature turn the air conditioner off and let the fans keep you cool."

But turn the fan off when you go out because the fan cools you, not the room, through evaporation.

The number of blades affects performance, as does the material, says McBride, adding that metal blade fans provide the best airflow. While single-blade fans appear more stylish, they don't move as much air as a three- or four-blade fan. "It is a personal choice as to the strength of the breeze: some people want the fan to go slowly, others prefer a strong wind."

Room size and ceiling height also matter. More than 350 sq ft may require two fans, says McBride. For maximum efficiency, a fan should hang no more than 2.4 metres above the floor. Alternatives include desk, wall and pedestal fans.