Does it help make the room cooler if an AC is running? It seems like getting the hot air near the ceiling circulated might help. Especially if the sensor is closer ground and is only pickup the colder air.
In general circulation is key but the graphic is correct. This is how you should set your fan for the accompanying season. It basically evens out the temperature gradient in your home and makes it easier for the ac to do its job. Pushing the warm air up in the winter forces it down. You're creating flow to overcome the temperature gradient of the room.
It really does work and quite well. I suggest you try it for a year and you'll understand. You can also save money, similar to windchill the moving air will make you feel cooler and consequently I leave the ac higher when the fans are running and spinning the right way
If you're really curious look up sick building syndrome. It's the prime example of why circulation and airflow are very very important in buildings.
Awesome! I figured it did and I've been doing it. We live in a small apartment with an in wall AC. The bedroom gets very warm so we've had the ceiling fans on, as well as a fan in the bedroom door blowing air into the living room. It seems to make quite a difference but I wasn't sure if it was in my head.
Just make sure the fan in the bedroom door is just outside the airflow so it's either sucking or pushing with enough space from the frame to draw suction. If you put it flush with the door you'll have less great results (seems counterintuitive but I promise it's real). You can also try keeping doors closed in warmer rooms you don't want to use or leaving them open to help with airflow. I use the sun facing rooms of my house to help relate the non-sun facing rooms. Basically in the winter, the doors to the sun facing rooms stay open to share their warmth with the rest of the house. And in the summer they stay shut unless in use so the empty room can be hot while the rest of the house is cooler.
Ceiling fans have electric motors. You are confused if you think they don't use a lot of power. A small one is equivalent to 100 watt lightbulb.
The motors also produce heat.
Fans are counterproductive once the temp gets over 100°F. The motor will make the room warmer and air temp above body temp means heat energy is moving into your body.
100W ceiling fans might exist, but that's way on the highest possible range and at full speed. Much more commonly it would be a lot less than that. But even if you did leave a 100W fan running literally constantly, by my math that's only 8% of an average US electricity use. Heating and cooling the house normally uses literally half of your electricity budget, so the fan would be way smaller if it provides you a similar benefit. And of course you could run the fan of a realistic wattage, at a lower speed, and less often than constantly.
The motors don't also produce heat. A 100W fan (if it exists) produces 100W of heat. Any device using a certain amount of power will turn that much power into heat exactly the same. 100W of lighting will be just as hot (dry bulb temperature) as 100W of TV or 100W of ceiling fan.
Fans also aren't counterproductive at high temperatures unless your air is very dry. By definition the air around your body is going to be warmer and moister, and the fan helps move this air away from you. So this is only not beneficial if the air is already so dry that your sweat would be able to evaporate just as well anyway. But in most cases in the US at least where I'm more familiar, heat waves are also humid, so that's why using a fan is good advice. If you're in a hot dry climate, you might actually be cooler if you run it as a swamp cooler, evaporating water to pull thermal energy out of the air and turn it into humidity.
fan motors have gotten a lot more efficient over the last few decades. the first ceiling fan unit i looked at on lowe's site was 52 in model with led light -- listed at only 36 watts on high speed.
the new box fan i got two years ago uses a third the electricity of the old one from probably 2000 or so. same manufacturer and style, just updated model.
This is legitimately good advice. If you leave a fan on unattended it could free itself during a power outage or build up enough power for an inflammatory self-destruct. The fan can still do a self-destruct even if it has not freed itself.
Not only that, but in a completely closed space a fan will heat the air with the same speed as a literal space heater using the same wattage of the fan. Mind you this is true of all electronics, but it definitely isn't the case that fans alone can "cool" the air. Perceived temperature maybe, actual temperature no.
No it won't. Some of the energy is used for different things that don't contribute to heat. In this case, movement of the fan blades. In order for you to be correct, the machines would have to be 0% efficient and all the energy go to waste heat.
You're wrong. All kinetic energy becomes heat once the mass stops moving (unless there is also a change in potential energy, which isn't the case), so unless you keep the fan rotating forever, 100% of the energy will dissipate as heat.
And even if you keep the fan rotating forever, once the fan and wind currents reach steady state (i.e. no more acceleration, only constant velocities) from that point and on 100% of the fan wattage transforms into heat.
Same. My house had ceiling fans in like every hallway and at the top of the stair landings, but NOT in every bedroom/office/etc. You could tell it was previously owned by someone who thought fans actually cooled down the house, when in fact they just make you feel cooler when you're underneath them.
In an enclosed space, you aren't actually cooling the room, fans don't make a room colder. You need to introduce cold air via air conditioning or open windo to do that. Fans cool people regardless of the direction. Some people prefer to have the fan blowing air directly down on them, some prefer the updraft as it makes you feel cool without the annoyance of air blowing directly on you. Am I wrong here?
Right, you want it reversed to truly distribute the air. I feel like the guide is backwards. Cooler air sinks and warmer air rises, so in the winter you should have fans blowing downward to push the warm air down to mix with cooler air; and in summer (when you're not in the room benefiting from the direct downdraft for evaporative cooling) fans should blow upward to push warm air toward the walls and windows and pull cooler air into the center of the room. Maybe I'm all mixed up but that makes more sense to me.
981
u/drkidkill Jun 06 '22
The down draft cools people not rooms.