1/34 This started out as a much shorter thread about a related topic, but Something Happened and now it's a #LifeHack#instructional thread on keeping your house comfortable and saving #money and the #environment, through the magic of air movement. It's also timely, what with it being the start of the northern-hemisphere summer and southern-hemisphere winter.
33/34 Ceiling fans virtually all let you use them spinning in both directions. When cooling your house, set the ceiling fan so that it is blowing down; the air moving directly down and over you gives you that evaporative cooling effect.
When heating the house, reverse the direction. It will gently pull air up in the room, and then it flows outward to the walls and then down to the floor, eliminating that cold layer of air that freezes your feet.
32/34 At level 4 and above, the one in my office starts throwing papers around the room, but you can't hear motor noise at all. I've turned the one in the bedroom all the way up just to test it, and it's still quiet, though the sheer volume of air moving does make a little sound.
They're made by Kichler, and I'm quite happy with them.
31/34 As one datapoint, I have two ceiling fans, in my office and my bedroom. They're both the same model, a 60-inch one made by a company named Kichler.
They have 3 sculpted blades, a DC brushless motor, 6 speeds, and are completely silent in operation at all of them as far as I can tell
30/34 Longer downrods are easily available, and increasing the distance from the fan blades to the ceiling just a little improves their efficiency and quietness quite a bit. There are diminishing returns, so you probably don't need to go longer than 60cm, unless you're hanging it from a vaulted ceiling and need to have it hang down much further to clear the ceiling at the lowest point.
29/34 If you have a tall ceiling, consider getting a longer #downrod (the part that supports the main fan body and connects it to the ceiling joint). By default, most fans come with a downrod that only places the blades no more than 30cm below the ceiling. They usually come with an even shorter one in case your ceiling is low. Don't use those, if you can help it - the #turbulence gets quite bad, reducing air movement and making a lot more #noise.
28/34 3. Distance between the ceiling and the plane of the fan blades' rotation. A ceiling fan will create more turbulence the closer to the ceiling the blades are rotating; increased turbulence reduces efficiency and increases noise.
27/34 But large fans' advantage is also because the longer blades, sweeping a larger area, are simply more efficient at stirring the air. 52-inch fans are reasonably common and are a lot more efficient than common 44-inch ones, and bigger are available.
Again, if you can afford it, buy the largest one that will reasonably fit in the room.
26/34 2. Size. The larger the fan is in diameter, the more efficiently it can move air. Partly this is because there's a pretty constant-size section near the hub that doesn't contribute to being able to move air, and the smaller the fan diameter, the larger the proportion of its area is dedicated to this useless bit.
25/34 1. Fan blade shape. Flat plywood blades suck. A good fan will have blades that are shaped and sculpted, changing profile the further out from the hub you go. They look more like airplane propeller shapes, for the same reasons airplanes want efficient blade shapes. Better-shaped blades will also generally mean fewer blades - rather than 4 or 5 flat-paddle blades, a good fan will come with 3, or even just 2, sculpted blades. The 2-blade ones really do look like an airplane propeller.
24/34 Other things that make a ceiling fan more energy-efficient, more efficient at moving air, and quieter, all other factors being equal, are the following.
23/34 The savings can be even greater because a shaded-pole motor will have a very limited number of speeds it can run at, while a brushless DC motor, because it is electronically controlled, can be made to turn at virtually any speed. They'll commonly have 6 or more speeds.
22/34 The single biggest thing you can do to reduce the energy consumption of a ceiling fan, for a given amount of air movement, is to ensure that it has a brushless DC motor.
Did I mention shaded-pole motors, though cheap, are really inefficient?
A brushless DC motor might use a third, or less, electricity compared to a shaded-pole one.
21/34 Those little motors aren't suitable for ceiling-fan use, though. A fan needs a lot more power and torque. Such motors aren't dirt cheap, and that's why you won't find them in cheapo ceiling fans. If the packaging of a ceiling fan doesn't say what type of motor is in it, #dollars to #donuts it's a shaded-pole motor. If it were anything else, they'd be bragging about it.
The motors in ceiling fans also need much heavier-duty ball bearings than the ones in little ventilation fans.
20/34 Brushless DC motors used to be exotic and expensive, because they require control electronics, but their cost disadvantage changed a long time ago, at least for small ones. The ventilation fans in computers and other equipment, for example, are virtually all DC brushless fans, and common sizes can be had for a few bucks.
What other type of motor is there, then, besides shaded-pole, that is appropriate for ceiling fan use?
Brushless DC motors, also known as electronically-commutated motors, which are a modern marvel, courtesy of the advance of electronics and semiconductors.
18/34 In my book, deliberately making people less happy so they're in the right frame of mind to #waste money on unnecessary products is evil.
I am not the only one on this planet who thinks capitalism would work a whole lot better if every marketing person on the planet was #yeeted into the #sun tomorrow.
17/34 The marketers then convince those unhappy people to buy their hocus-pocus product that, by sheer happenstance, "cures" their problem that they didn't have in the first place.
They also exist to convince you to buy disposable products instead of long-lasting, repairable ones, helping to destroy the environment and use more natural #resources.
15/34 So if you see "AC induction motor" on a ceiling fan's box or datasheet, you know two things:
One, it's just a cheap shaded-pole motor, and you don't want it.
And two, that manufacturer is lying to you and you shouldn't trust them with your money, on this product or any other, even if that other product hasn't been pumped up as something it isn't by the #wankers in #marketing.
14/34 No ceiling fan I've seen uses this "real" type of induction motor. There may be some out there, but I suspect they would be monstrous commercial/industrial units with diameters of ten feet or more.
13/34 This is kinda-sorta-maybe-partly-technically true, at least enough to defeat a #lawsuit, but it's #misleading as hell. Deliberately so.
"Induction motor" is generally understood to be something else entirely - a motor with stator coils that induce a magnetic field in another coil in the rotor, improving power and efficiency. You'll find them in some HVAC equipment, table saws and other stationary tools, and various other places.
11/34 Cheap / "traditional" ceiling fans also use an electric motor design known as a "shaded pole" motor. These are used because they're cheap to make, and simple (and therefore cheap) to speed-control, by just placing a capacitor of varying size in the circuit.
10/34 You're probably familiar with a typical "standard" #CeilingFan -- commonly from brands like Hampton Bay and similar.
Small, entry-level models will have total diameters of 44 inches or smaller. They come with stamped plywood blades, which are cheap to make, but which are inefficient at moving air because the unoptimized blade shape -- i.e., flat -- creates too much turbulence, wasting energy. It also creates more #noise.
Add comment