How To Turn Off An Attic Fan?

Turning off an attic fan is often a confusing task especially if the fan was installed by your previous owner. Often the new owners are unaware of the location of the attic fan switch so this can be bothersome to many.

An attic fan can be turned off by turning up the temperature setting on its thermostat. This thermostat is located in the attic close to the attic fan so in order to do this, you will have to go into the attic. Some attic fans also come with a humidistat, so in this case, make sure that you turn up the humidistat settings too. If you forget to turn up the humidistat setting the fan will run when the humidity level is reached even if the attic temperature is below the thermostat setting. It is better to turn up the temperature and humidity settings to their top values to avoid the fan from running in any event.

How to turn off an attic fan

Why is turning off an attic fan such a big deal? Isn’t there a simple switch that can do this?

Attic fans do not come with wall switches. These fans are designed to run the whole day and night without stopping. In addition, their energy consumption is meager, so you don’t have to worry about heavy energy bills. So many people don’t opt to install a wall switch controller for attic fans and instead they are connected directly to the mains.

How are attic fans controlled and how to turn them off?

Attic fans can be controlled by either thermostat, remote controllers, smart devices, or a combination of all these. Here is how to tun them all off;

1. Turning off a thermostat controlled attic fan

The majority of attic fans come with an inbuilt thermostat. On this, you can set a temperature above which the attic fans should start running. This temperature setting depends on the area you live in; for a hot climate, the temperature is usually set high, and for a cool climate, the temperature is set at a lower value. In both cases, this temperature value should be more than the outside temperature.

If you set the thermostat temperature to a value lower than the outside temperature, the fan will run non-stop. This is because attic fans cool the attic by drawing in air from the outside, so it can never cool the attic to a temperature lower than outside.

As mentioned before, some attic fan models come with a humidistat in addition to the thermostat. The humidistat detects the humidity in the attic and turns on the fan when this humidity level goes higher than the humidity value set on it. If your attic fan also has a humidistat, then make sure that the humidity value set on it is always higher than outside. Otherwise, the fan will keep running non-stop becuase the attic will never have a lower humidity level than the outside air.

Some attic fan thermostats come with two temperature settings where you can set two temperature values. These types of attic fans have either 2-speed or variable speed motors. In this case you can set a lower temperature value where the fan runs at its low speed and a high temperature value where it runs at the highest speed. This setting can improve the efficiency of the attic ventilation.

To turn off an attic fan that is controlled by a thermostat or both humidistat and thermostat, just turn up the values of the setting to the max.

2. Turning off a remote controlled attic fans

Some attic fan models come with an inbuilt remote control, and for some, you can optionally buy a remote control kit (like this one). In addition, these fans will also have either a thermostat or both a thermostat and humidistat. With the remote, you can control the fan speed, temperature, and humidity settings, and you can even turn the fan off from your living areas. Remote controllers are a very convenient option to control attic fans however, they are not popular since many people don’t see the need to constantly control these fans.

Image of remote control kit

The remote control kit can be installed DIY but make sure that it is suitable for your fan. These kits are not compatible with all fan models, they are only built for specific brands or models.

So as you guessed it is pretty easy to turn off an attic fan that is controlled by a remote controller. Just press the power off button and the fan will turn off!

3. Turning off an attic fan with smart switches

Attic fans can be controlled via Alexa, Google Home, or any such devices. However, these smart devices do not control the fan directly. There are specially designed smart plugs (like this one) that can be controlled by Alexa, Google Nest, etc. Here, the attic fan is connected to the mains via a smart plug which turns on and off based on the commands it receives from the smart devices.

image of a smart switch for attic fans
A smart switch

If your attic fan is controlled by a smart switch just tell your Alexa or Google device to turn it off.

4. Turning off attic fans with speed controller switches and wall switches

Even though it is not common to install a wall switch for an attic fan it is possible to do so if you decide you want to turn it off without crawling into your attic. You can use a regular wall switch to turn the fan on and off, or you can use a speed controller. The advantage of the speed controller is that you can easily vary the fan’s speed, set it to a high speed so the attic will cool faster. However, speed controllers are not compatible will all models of attic fans while wall switches are.

Image of an attic fan speed controller

The problem with speed controllers is that the motors of some attic fan are made only to run on a single speed, so electrically varying its speed may damage the motor and void its warranty.

If your attic fan has a wall switch simply turn it off to stop the fan from running.

My attic fan runs slowly even though it is turned off, why?

Attic fans aka attic power ventilators are used to exhaust the hot attic air forcefully. Even though the fan is switched off the hot air from the attic will continue to move out but slowly. This air movement is enough to turn the blades of the attic fan (like the wind moves a windmill). This is completely normal and there is nothing to worry about. But if the fan is running at full speed, then it is still electrically connected to the mains. In this case you will need to troubleshoot the fan.

If your attic fan is running constantly without turning off I suggest you read my article – common attic fan problems and their solutions.

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Charles John

Experienced HVAC technician with 8 years of experience in the industry. Capable of handling all sorts of heating and cooling equipment as well as proficient in operational management, construction-related techniques such as preventative maintenance, electrical troubleshooting and AutoCAD

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