How To Install Window Fans Perfectly – Tips & Tricks

The thing that removes heat from your room is fan. It is one of the most essential equipment in our daily life. Window fans are usually cheap, much more environmentally friendly than air conditioning equipment. The best places to install window fans are in hot areas during the day and cold at night. The application is to cool the house at night, inducing external air, avoiding using a climate during the day, when the fans are stored. 

Since this method uses electrical energy at night and not at peak times, as a climate would, it helps a lot in areas where power outages happen. To make use of window fans, follow the instructions below.

Step – 1:

Check if the conditions are appropriate for using window fans.

Step – 2:

If the temperature is uncomfortable, hot and/or humid, day and night, then this method is not appropriate. If the heat is only in the day, this method is recommended to cool the house at night.

  • If you live in an industrial area, this method is not recommended.
  • This method is not suitable for windows that do not have mosquito nets, as insects can invade it, even cats would be injured, so if you do not have protectors, do not use this method.
  • In high crime areas, open windows could be used as a means of entry for criminals.
  • When the noises outside the house are very scandalous the noise of the fan could mask these.

Step – 3: Choose the fans

That the size of the fan adjusts with the dimension of the window. Avoid those that are larger than the window, such as placing it close to the window, outside the window frame, results are low. The home should have as many windows to induce air as windows to expel it (keep in mind that smaller, less powerful fans can count them as a portion of the others). If you cannot balance the inputs with the outputs, then the inputs are larger, so you will get more internal pressure which will prevent insects from entering the output windows

Step – 4: Choose the windows

With this you determine which windows induce air and which expel it. There are many things to consider:

  • Windows that will induce air are cool, shaded windows.
  • Try to go in favor of the wind, but the induction fans where the wind hits, the days that the wind hits hard, you will not need to turn them on.
  • When operating the fans, keep the doors open to facilitate airflow. Take care that the airflow is in one direction as best as possible, to take advantage of the maximum flow.
  • For multi-level homes, consider that heat builds up in the upper rooms, including the attic, if possible keep the attic door open.
  • Avoid inducing air near the garbage can or parking lots, where gases and bad odors will enter the house. Induce the air in the gardens or next to the trees so that induction is pleasant and pleasant, unless pollen is a problem for you.
  • Do not induce air near a refrigerator/freezer, it may increase the electrical consumption of the same.
  • Do not induce air in an office, it will blow up the papers, if that is the case, secure your stationery first.
  • Avoid inducing air in rooms with valuables, such as an antique desk or expensive oriental rug, to prevent water damage.
  • Rooms where induction fans are installed cool first and faster than rooms that blow hot air.

Step – 5: Place the fans on the window

Adjust the placement of the fans with the window itself so that there are no air leaks. Leaks recirculate the air with poor effect, because if the air is recirculated at the same point, the motor would heat the air and not cool the room.

Step – 6: Seal the gaps between the window and the fan frame with foam tape

If the fan induces air, it will want to return as it enters a high-pressure area. Sealing the edges with foam tape will prevent this from happening. Fans that blow hot air are more difficult to seal since the air outside wants to enter a lower pressure area, so the seal will have to be made tighter, with cardboard and tight tape.

Step – 7: When the outside of the house is cooler than the inside, it’s time to turn on the fans.

When the house is cool enough, remove the fans and close the windows. A useful rule of thumb is that the interior temperature of the house in the day should be the average of the external temperature in the day and the internal temperature at night. 

So if you want to reach an indoor temperature of 25 C during the day and an external temperature of 35 C, you should cool the house at 15 C at night. This may vary from house to house, but you can keep this rule in mind until you have a better estimation formula. In this case, the fans can be turned off at night, if the indoor temperature is below 15C.


  • Install the exhaust fans as high as you can. On the second floor for example. Since the hot air is lighter, the exhaust fans will remove it.
  • Close the blinds during the day in sunny areas, to avoid internal overheating.
  • Remove the fans from the windows when not in use, this will help maintain the temperature, but this could be cumbersome. In such a case, the fans may remain on the window. However on rainy days it is advisable to remove them, if possible, to prevent water from entering the house.
  • The inconvenience of this method is the low night temperatures. Wearing warm clothing and a thin blanket will help.
  • If ventilation is not appropriate in your home, remove the fans from the window, close the window, and move them closer to the bedroom, in the direct direction of your bed to cool off directly. Don’t forget to turn it off in the morning, when nobody needs them.
  • Fan maintenance:
    • If you use the fans day and night, you will shorten their useful life, especially if you leave them on in the rain. With proper maintenance, you will extend the life of these.
    • Do not operate a fan that works improperly, nor if it has beaten blades or smells of burning, it can catch fire.
    • Lubricate them frequently so they start and spin fast like new to avoid noise and heat damage. Disconnect the fan, take it to the garage, then lubricate around the arrow, rear and front, you will need to disassemble the casing to clean the rotor, use WD40 or equivalent, assemble the casing and turn the blades by hand to feel the lubricant do his work. Avoid lubricating electrical parts like the winding or ignition switch. Let the fan rest for about 2 days so that the solvents evaporate and install it as an extractor fan, so that it does not induce odor residues to the house.
    • Another common problem is a power failure. It is usually some desoldered wire. If you have the ability, release it yourself. Another point is the switch, maximum if it is multiple. You can replace it with an equal one or choose the speed you like and install an individual switch.
  • Fan cleaning:
    • The blades tend to get dirty due to continuous operation with the air they circulate, they also lift grease and dirt, which can contaminate the air they induce.
    • Unplug the fan, use a damp cloth with window cleaner or dish detergent. Similarly, you must remove the fan from the window and take it to the garage to clean it.
    • You can also postpone maintenance, having a few more in reserve, so that you change them for ones that look new, while you plan when to clean the ones you removed.
  • The fans cool in 3 different ways:
    • Inducing fresh air and expelling hot air (the topic of this article).
    • Replacing hot, humid air with cooler air. Ceiling fans for example.
    • Moistening the air and cooling it in the direction of a person. (Washed air) recommended in desert areas, where even sweat cools, a humid breeze is appreciated, such as when you go out to bathe, or from a pool, etc.
  • Some security doors used in high crime areas have windows, so inductive fans can be embedded. If you have a duct installed general induction system, leave the interior doors open without compromising the security of the interior.
  • You can increase the flow of cold air induced temporarily (approx. 1 hr) by placing a towel moistened in ice water in front of the induction fans. The size of the towel should be the size of the fans. The fans will send pressurized air over the towel, taking a cool breeze, do not do this if you think the towel is wetting the fan cord or outlet.
  • If the house is not built to handle the electrical load of a central air unit, window fans are less demanding on the electrical system because they require less power, are used outside of peak hours, and are evenly distributed throughout the House.


  • If you use this method, prepare yourself to experience changes in temperatures of 10 C between day and night inside the house, since the fans do not help control the temperature as a climate does.
  • Do not leave the fans on the window during the rains, the humidity can infiltrate and damage the house not only the fan. Wide layered roofs would prevent this unless the rain is accompanied by winds.
  • Don’t use a faulty fan. If the fan does not rotate as fast as ever or it smells burnt, turn the fan off immediately, the risk of fire is latent.
  • Do not turn on the fans where there are small children, they may lose a finger or the whole hand, even when their fans have cages, they allow a child’s finger to be inserted like a pencil or pen.
  • Take care of the connections.
    • Do not bite them with the window, do not allow them to cross the room, because it can make you trip. Make an appropriate electrical installation in the walls with adequate gauge.
    • Do not hide the extensions under the mat, it will catch fire at high cable temperatures.
  • Take care that the fans do not fall from the window.
  • Avoid having the fans very close to the ground level. During the night they can introduce excessive humidity that results in mold.
  • The window fan method can be rough, inconvenient, to your wooden furniture, because variations in temperature and humidity can cause cracks and deformations in them.

Things you will need

  • Window fans (the more the better, up to the total number of windows in the home). There are models designed for windows that include rain protection, insulation and an easy-to-remove system. Some even have automatic reversible mode.
  • Use electrical installations with cables of the proper gauge.
  • Indoor and outdoor thermometers (optional).
  • Automatic time starters, which will turn the fans on and off at scheduled times. This would imply leaving the fans stationary, causing a loss of efficiency, unless you can close the windows or the induction fans turn them on before and turn them off after the extraction fans, this so as not to generate a negative pressure inside the home.

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