It's a curious thought of "could you close a room and point a fan at it and noticeably cool off a room?"
This would be kind of running a mini-split AC to the rooms using water as the refrigerant instead of what hvac normally runs.
It's not a "this is the best choice" or even "this is a better choice than opening the windows" but rather a "if you did this, would it work? kind of?"
Agreed. In my own experience, it's much more effective when cooling a room to pull the cool air in than to try to exhaust the hot air from the entire house so that cool air will eventually trickle into the room you're trying to cool. Changing from pushing the air out to pulling it in directly was an epiphany for me when I was younger and lead to many nights of better sleep.
Even better, now that I own my own house, is a high powered fan in one window pushing the air out and another (lower-powered) fan in a different room pulling the air in with an additional window open. You can stand in front of the open window and feel the additional cool air streaming in. It's a beautiful thing.
Assuming you want to cool down the room and there is 1 window:
Open the window in the room and open the door to the room. Ideally open a window somewhere else in the building and make sure there is a potential airflow from that other window to the one in your room.
Place the fan in the window of the room you want to cool down and let it blow outwards. Alternatively you can place the fan in the same way in that other window you opened.
Into the room I'm cooling. I suppose it would be possible in theory to do so, but the particular layout of the room makes it difficult to impossible to exhaust both the AC and computer, I think.
It’s cheating, a bit, to live in a place that drops 20-40 F at night … but even if we didn’t, the ability to turn every open window into an air conditioner is a great trick.
"If you have a smallish house and a centrally located fan, a whole house fan is amazing. The rooms get cooler and the attic gets cooler too. You can shut doors to make a specific room cool in minutes. Seriously one of the best things you can do to a house imo."
I just added a whole house fan to my home in the bay area and it works very well - the temperature drops by as much as 30+ degrees from daytime to night time here.
I really appreciate the simplicity of not having AC infrastructure anywhere in my house.
However, I have lived in other climates, like Minnesota, where the nighttime temperature does not drop much at all and I am not sure it would be worth the effort. If it was a box to tick for new construction, then sure - but I wouldn't go out of my way to add it to a house after the fact ...
Let's further assume that I'd rather have the room cooler than 30C. Also, regardless of which direction the fan will blow, there also needs to be another place for air to move into and out of the room. So let's also assume that the window is the only opening, but the fan doesn't fill the opening produced by raising the window. One more assumption: I can point the fan with freedom in most any direction once it's placed.
I believe I'd pull the cooler air into the room by having the air blow in. I might also point the fan up and away from the other side of the window (up because I want to disturb/displace the warm air higher in the room; away from the non-fan side because I don't want my cool air to be pushed right back out.)
I don't want to cool the warmer air, I want to replace it with cooler air.
Yes, it's best if you can create an airflow from bottom to top in a multi-story place.
Getting a draft through your entire place is also good.
What I suggest with the fan works, when you can't do either of the two above.
> I don't see that it matters much which way the fan is blowing. What matters is the air exchange, which is about creating an airflow.
The latter explains the former. A simple experiment: sit 2m in front of a running fan, then sit 2m behind a running fan. In front, you will feel lots of airflow, behind you will feel almost nothing.
That's because the fan 'pulls' air in a diffuse manner, but pushes it as a directed bundle.
It's probably equally as effective to put your fan outside the home and point it inwards, or to put it inwards the home and point it outwards. Alas, most people can only put the fan _inside_ their home, perhaps at the window at best. But that's less effective at exchanging air with the outside than pointing it outwards.
> If you have a single level, the fan will just create a slight pressure difference in one direction or the other. You just need to open several windows, preferably on opposite sides of the room, and if you use a fan to pull cool air in that creates a positive pressure inside the room, which will force the warm air to be exhausted through the other open windows. If the fan is blowing warm air out, then the room pressure will be negative relative to the outside, and cool air will be pulled in through the other open windows.
To use your terminology: the fan is better at pushing air in a concrete direction, than at pulling air from a specific direction.
So, in a lot of homes, fans usually blow air towards the inside. This makes sense if you’re trying to keep the AC from escaping, right? But what about keeping the air fresh?
The results of this video seem very counterintuitive to me. They seem to suggest the best way is to have a table fan pointing out of a window instead of keeping the pedestal pointed inwards. This is something that no one does (Even the makers advertise its use as inward pointing)
Most replies intelligently include open windows. Running an electric fan in a closed room with unopened or no windows may prove fatal and can lead to irreversible Fan Death. It's not a good way to go.
Can anyone speak to the advice I received years ago (on move-in day at a college dorm with no AC) that two box fans--one pointed outward and one pointed inward--would be more effective than having them both aimed inward? Supposedly helps create circulation, but, I'm not sure I buy it.
What an odd article. I'd love to know more about the author's background where he's just now considering airflow in a home. Maybe it seems strange to me since I was in my late 30's before I lived anywhere that had air conditioning, so open windows, fans, cross-drafts, and general air flow were the norm.
I also want to see what happens when the author discovers the whole house fan. My very first house had one and it was amazing. Crack open a window in each room and activate the fan. Instant breeze and air circulation in every room with somewhere around 6-8 air changes per hour.
We had a whole-house fan like this in Sacramento. It worked especially well there because (1) it was not humid, and (2) the temperature at night was much lower than in the daytime. It might be 100° during the day, but it would be in the 60s at night.
Fans like this aren't nearly as effective if either of these conditions is not met — then you're just pulling in air that is somewhat less uncomfortable each night, instead of getting truly refreshed.
Yes, but that doesn’t change the inefficiencies I mentioned, which are why it isn’t often done. It is done sometimes - I had a home with such a setup - but you’re much better off dropping a few hundred $$ on a proper whole house fan.
This would be kind of running a mini-split AC to the rooms using water as the refrigerant instead of what hvac normally runs.
It's not a "this is the best choice" or even "this is a better choice than opening the windows" but rather a "if you did this, would it work? kind of?"
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