You can have fans blowing out of the windows on the upper level to exhaust the warm air trapped there, says Chris Regan, an engineer and CR tester of AC units. And when the outside temperature starts to drop, you can pair that with fans blowing inward in shadier rooms to maximize the airflow in your home.
Anyway, to answer the question at hand, it is much more efficient to blow outward with another window or two open somewhere else in the house. It creates suction that will pull the cool air in from the other open window. Having a fan blowing inward does not even begin to compare.
Does pointing my fan out the window help cool down a room? Yes, placing your fan in front of your window allows cold fresh air to circulate around your room instead of just blowing warm air. Yes, it draws the air in, circulates it and brings the temperature right down.
Open a window and place a window fan or box fan on the sill to blow inside or outside the house, be sure that it is perpendicular to the prevailing wind (ie. if your main wind direction is south or north then put the fan in a west or east side window). This is the best if you have a very low or nonexistent breeze.
Ventilation: Good ventilation is important. If closing windows makes the air stuffy, consider using a fan to improve air circulation. In summary, on very hot days, it's generally better to close windows and use a fan to maintain a cooler indoor environment, especially if the outside air is warmer.
Consider timing when you use a window fan, he says. “You want to window fan when it's cooler outside the home than inside, typically overnight or early morning,” and “direction is also key: the fan should face inward, so it draws the cooler air into your abode and blows it in your direction.”
15 minutes is enough to air the house properly
A window open for 15 minutes is enough! That's it. With this method, only the indoor air will be cooled.
Create cross ventilation by opening windows on opposite sides of the house to promote air circulation. Close curtains, blinds, or shades during the hottest parts of the day to block out direct sunlight and heat. Utilize exhaust fans in bathrooms and kitchens to remove hot air and humidity from these spaces.
'If you're looking for relief from the heat, it's best to put ice in front of a fan, not behind it,' he says. 'When this happens, the cold air from outside will enter through the open window, causing air pressure that pushes hot air out of your house naturally.
Ceiling fans, tower fans, and box fans typically range from 40 to 100 watts of power when operating at full speed. This amount of electricity is not very much, especially compared to the other appliances and electronics in your home. At its lowest setting, a fan may only use about 10 to 30 watts.
Point the fan out of the highest window
This will ensure that stuffy air is drawn out of your space, lowering the room temperature and preventing humidity.
If it's safe to do so, open doors and windows as much as you can to bring in fresh, outdoor air. While it's better to open them widely, even having a window cracked open slightly can help. If you can, open multiple doors and windows to allow more fresh air to move inside.
Place a fan in one window facing out, so the air in the room is being blown out the window. You'll want to make this fit as well as possible, so there's no space open in the window–the fan should cover the open window space. In my kids' room, they have a window that opens up, which is ideal.
To bring cooler air from outside, place the fan near an open window screen or door. The air should blow into the room. To take hot air out of the room, face the front of the fan towards an open window screen or door. The air should blow out of the room.
To cool down a room without AC, make sure to use window fans, ceiling fans, or tower fans. Keep your room cooler all day by covering windows to prevent heat from sunlight coming in. You can also reduce humidity, block air leaks, and ventilate out hot air to cool your entire home.
You can cool a room with just one window and one fan. Place a box fan in the window or a pedestal fan within 5 feet of the window. When the air is cooler outside than it is inside, point the air so it blows into the house.
Lay the cloth over the fan. As it blows the air out, it'll circulate through the cloth and the air will feel cooler. Make sure that the cloth cannot get caught on the fan in any way at all––if this is a possibility, don't use this method. Replace the cloth frequently, as they dry out.
Another trick is for homes with multiple stories: face the window fan into the house on your lowest story to bring in the cooler air. The warmer portion of this air will naturally rise to the top floor, so place a window fan up there, too—on the other side of the home, facing out—to expel the heat.
While it might sound strange, you can cool down a room fast with this easy hack. Simply fill a metal or glass bowl full of ice, place it in front of your fan, turn it on, and enjoy the cooling effects.
According to the GHI, placing a bucket of ice in front of a fan as a homemade AC unit is just as effective. 'As the air passes over the ice it will be chilled and will circulate refreshingly cold air around the room,' they explain.
You can have fans blowing out of the windows on the upper level to exhaust the warm air trapped there, says Chris Regan, an engineer and CR tester of AC units. And when the outside temperature starts to drop, you can pair that with fans blowing inward in shadier rooms to maximize the airflow in your home.
Without proper ventilation in the house, mould and moisture problems develop. These are the possible consequences: Damage to the structural health of the home. Moisture problems and persistent mould patches.
Using fans while the windows and doors are open will get air moving even faster. Use a dehumidifier if the air feels and moist stuffy. If you're in the bathroom or kitchen, turn on the exhaust fan to get air moving. In the kitchen, you can also turn on the range hood fan (if you have one).