One of the kitchen essentials, if you are a cooking freak, is the vent hood. Why? Because you don’t want the smoke and fume of your favorite dish to water up your eyes, or distract you from burning it.

This is why you need a vent hood. It does wonders by removing not only the smoke and fume but also the grease and oils to keep the kitchen neat and tidy. 

But sometimes, like any other electric equipment, it malfunctions. It turns on on its own. Like a freak horror movie, you wonder why does my vent hood turn on by itself! Well, there are a few possibilities behind this than the paranormal.

The temperature sensor might be damaged, or the humidity sensor. Also, the wiring and circuit board might be at fault. For any of these four reasons, your vent hood will turn on by itself. And we are going to explain to you all about it. 

Reasons Your Vent Hood Turns On By Itself | With Solutions 

There are four main reasons why our vent hood keeps on turning by itself. Some of them are easy fixes and some, you do need a professional to look at.

Let’s get into them and find out which one is causing you trouble. 

(A) Malfunction Of Sensors

One of the main causes for a vent hood to turn on by itself is the sensor malfunction. There are two sensor that works on a range hood. 

1. Temperature Sensor

Temperature sensors activate the hood when there is a sudden change. They are tiny little devices that are placed under the hood and on top of the cooktop. If it is faulty and stays at a constant temperature, the vent hood will turn on by itself. 

Solution: Get a multimeter and check the resistance of the sensor. If the sensor is working perfectly, then the resistance will change. But if it is faulty, then it will remain the same. And you should get it changed. 

2. Humidity Sensor

Another sensor that lets the vent hood work is the humidity sensor. This sends a signal to the range hood to turn on when there is fume and smoke creating moisture around the kitchen. But when the humidity sensor is faulty, it will send signals to the fan to turn on even if there is no humidity.

Solution: Again the multimeter and resistance check will get you the right answer. If the resistance is constant, you have a faulty humidity sensor and you will need to change it. 

(B) Faulty Electrical Components

Apart from the sensors and other components, the electrical wiring and circuits can be faulty. And you need them in pristine condition for the vent hood to work properly. 

1. Wiring Fault Or Damage

Although it is unlikely, but vent hood wiring may get damaged. As it deals with a lot of heat, fume, grease, and oil, the possibility of melting a wire casing is always there. Also, sometimes there is a factory fault that comes to light after use. 

Solution: You can check the wiring with a multimeter. If there is a problem with the wiring, you have to contact the manufacturer for a replacement or fix.

2. Circuit Board Damage

And lastly one of the most serious cases of damage is the circuit board damage. It can happen and when it does, everything falls out of place in the vent hood. Your hood will turn on and off by itself, it won’t turn on, or function in any way. As it is the main board of your vent hood, you have nothing to do if it gets damaged.

Solution: Call a professional electrician to have a look at the board. If it is really damaged, you should take it to the manufacturer and get it changed or replaced if the warranty is available. 

FAQs (Frequently Asked Questions and Answers)

Why does my Broan range hood fan turn on by itself?

If your stove and kitchen temperature don’t cool down, it will trigger the Broan range hood fan to turn on by itself. Also, there is a chance that the temperature and humidity sensors have gone bad. You can check it with a multimeter. And for other troubleshooting, you can go for the manual of your range hood. 

Should a vent hood be on its own circuit?

Yes. Although less powerful, most vent hoods come with their own circuit. It can also share circuits from other appliances, but it’s getting less common. 

Why does my Kitchenaid hood fan turn on by itself?

Kitchenaid hood fans are turned on by the temperature or humidity sensor. If they are sensing any temperature and humidity, it will turn off after the kitchen and stove are cooled down. If the problem persists, you can contact the manufacturer for assistance.

What is the difference between extractor fan and exhaust fan?

There is no significant difference in operation between an extractor fan and an exhaust fan. Both of them extract air out of the building. But an extractor fan can be a bit more powerful than an exhaust fan and is not suitable for home use. 

Conclusion

Vent hoods are not only a necessity but an essential for any kitchen. Especially if you are cooking most of the meals at home. So if the vent hood keeps on turning on by itself, it is time to see the doctor (electrician). And get the warranty to replace or fix if it is still available.