Currently "220V AC Cooling Fan", walls and windows three markets. Look better, you can install on the bedroom ceiling, the fan duct is shorter, and therefore need to buy matching pipe exhaust pipe installation. Since this is a one-way operation of the exhaust fan, the indoor air can be discharged, the length of the exhaust pipe strength is running, when coupled with weakened in the kitchen, so only suitable for installation in air flow better life, not suitable for installation , bathroom and other places, the price of 100 yuan. Wall-mounted small "220V AC Cooling Fan", can be embedded in the top of the window, but because of the narrow cross-section of the vent, causing ventilation is weak, so only suitable space for installation in a bathroom or other small enclosed balcony. Window exhaust fan is different from the previous two, it has a single, dual operating mode, indoor air can be discharged, but also complement the outdoor fresh air into the room, therefore, bedroom, kitchen and other rooms install exhaust window "220V AC Cooling Fan" is the most suitable. For many people crowded in the indoor environment, indoor air circulation, such as basements, which tend to live in a dark and humid environment, without a breath of fresh air, and this is entirely conceivable that these people's health.