Everyone speaks about remembering to turn your ceiling fan onto warming mode in winter. They say it helps to make a room feel warmer, which can reduce your heating bill.
I always wondered how effective this setting actually is and if it is worthwhile flipping the switch and running a ceiling fan in the winter as well. In this article, I am going to present my findings to you and we’ll distinguish between the fan direction making a difference and the fan direction being effective for its intended purpose.
Ceiling fan direction matters in that the summer mode will blow air onto a room’s occupants in winter, causing wind chill, and the winter mode won’t blow air onto the occupants in summer, depriving them of wind chill. Summer mode is effective, but winter mode is not unless there’s a heat source in the room.
How Ceiling Fans Cause Air Movement
Ceiling fan blades are set at an angle and this is what allows them to move air in a room.
How the Fan Works in the Summer/Cooling Setting
When your fan is in the summer/cooling setting, it turns anti-clockwise and the blades move in the direction of the “high” side.
As the blades turn, they scoop the air and push it down in the direction of the blade’s pitch. Air above and around the fan is pulled towards it (to replace the downward displaced air) and this too is then scooped by the blades and pushed down.
Occupants of the room, specifically those directly below the fan, will feel the downdraft and will be cooled by the wind chill effect, even though the actual temperature of the room remains unchanged unless cool air is artificially introduced by the AC.
While the effects of the ceiling fan are most noticeable directly below it, the movement of air throughout the whole room is affected, although not as effectively as with an air circulator.
This is because the air being pushed down by the fan displaces the air that was there and pushes it outward through the room. This air then moves upward along the sides of the room, near the walls, to replace the air that is being drawn to the fan and pushed down.
How the Fan Works in the Winter/Warming Setting
When your fan is in the winter/warming setting, it turns clockwise and the blades move in the direction of the “low” side.
As the blades turn, they push the air up along the blade’s pitch towards the ceiling. This displaces the warm air that has collected there due to the natural propensity of hot air to rise. The warm air moves along the ceiling, towards the edges of the room.
Air below and around the fan is pulled towards it, replacing the air that was pushed towards the ceiling. As the air reaches the fan blades, it too is pushed upwards.
When air below the fan moves up, it creates a vacuum effect that pulls air from the sides of the room into the center of the room. This, in turn, pulls the warm air around the perimeter of the ceiling down the walls to the areas where it is more likely to come into contact with occupants.
Are the Settings Effective?
The Summer/Cooling Setting Is Effective
The wind chill factor is a scientifically recognized phenomenon and one that we have all experienced for ourselves. There is no denying that when a ceiling fan blows air over you, you feel a lot cooler than when the air was still, even though the temperature remains the same.
The effectiveness of the ceiling fan would be enhanced by the addition of cooled air from an AC (and vice versa), which means that using the ceiling fan can mean you set your AC to a less cold setting and save on electricity costs. Obviously, you would need to make sure that the cost of running the fan does not match or exceed the amount saved.
Isn’t Warm Air Pulled Down?
If you are like me, then you are thinking that if the fan is pulling air in from above and around it, surely that means that the warm air sitting against the ceiling would be pushed down as well. And you’re right; it is.
However, the air above the fan is not likely to be wildly warmer than the air in the rest of the room, so moving it down will not be like blasting you with a hair dryer.
Furthermore, the collection of warmer air against the ceiling is not something that happens rapidly, so within the first few seconds of the ceiling fan being on the collected, warmer air will be dispersed among the rest of the room’s air, and no longer discernable.
The Winter/Warming Setting is Not Effective
If the warm air is quickly dispersed throughout the room in the cooling setting, what makes it different when the air is displaced by the winter setting? The answer to this is most probably “not much”.
Once the warm air has been displaced and pushed down, it will disperse, or more specifically, the heat will disperse to the air around it, “diluting” the warmth. The overall temperature of the room might increase as a result, but it is unlikely to be increased in any noticeable way.
This is because, in a cold room, the “warm” air at the ceiling is only going to be warm in comparison to the rest of the air. It will be the air that has been marginally heated by body temperatures, light bulbs (if they are not LEDs), or furniture that retained some heat when it caught the afternoon sunshine. It will not be heater-hot—not anywhere near it.
Doesn’t the Moving Air Create Wind Chill?
If the air is moving throughout the room when the fan is set to winter mode, then it makes sense that there would be a wind chill effect just like that which makes the summer setting effective. When examined closely, however, you will see why this is not the case.
The speed at which air moves depends on the rotational speed of the fan, yes, but also on the rate of passive air movement, which depends on the space it has to fill.
The area between the fan and the ceiling is much smaller than that between the fan and the floor. No matter how fast the fan spins, it can only push as much air upwards as will fit in this space (displacing the air that is already there).
Thus, the rate at which air is passively pulled up towards the fan by the movement of air above the fan will be slow enough that you will not really be able to discern it. Or it may feel like a “normal” movement of air as opposed to an artificially generated one.
Adding a Heat Source Increases Effectiveness
If you were to install a heat source in the room, something like a fireplace or a space heater, even underfloor heating systems, then the winter setting on your ceiling fan would become more effective.
This is because it provides a gentle flow of air that would pull the heat through the room and also keep it from collecting at the ceiling and leaving the lower portions of the room cold.
Ceiling Fan Direction Makes a Difference
The direction in which your ceiling fan spins does make a difference. If you were to turn on the summer setting in winter, you will be blasted with air, which will make you colder. If you were to turn on the winter mode in summer, you will not reap the benefits of wind chill.
However, it is my opinion that a dual-directional ceiling fan is not worthwhile unless you are going to be using an external heat source in conjunction with the winter setting on the fan, or you would like to create air movement to prevent rooms from feeling stuffy in the winter without having air blown onto you.
In addition, you could use the ceiling fan as a purely air circulation device and not a cooling/heating device. In this case, you can use the reverse directionality to improve air distribution throughout the house when you put it in locations like at the top of a stairway.
Because ceiling fan direction makes a difference, when the fan starts switching directions by itself, it can be quite annoying. Happily, there are ways to fix this!
It can also be frustrating when the reverse switch stops working altogether. But there are remedies for this as well.
Sources
https://www.youtube.com/watch?v=B49oCQn0Zvo