How Much Electricity Do Exhaust Fans Use?

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If you look at all the electrical appliances at your home, be it your bathroom, garage, kitchen, or more, you will find that a 20-amp circuit can easily get the job done. That is, of course, if there aren’t any energy-intensive appliances installed, such as an air conditioner or a space heater.

Exhaust fans are a major part of kitchen and bathroom appliances as they remove moist and hot air from bathrooms and kitchens to improve ventilation, effectively cooling the place down, removing chances of mold and more importantly; keeping your mirror from fogging up. However, how much electricity do exhaust fans use? Is it okay to keep them running?

Their energy usage varies from their size and function; comparing energy consumption to a lightbulb all the way to being extremely energy-intensive. Basic exhaust fans that you are most likely to find in small storerooms or bathrooms use no more than 6 watts and can keep running for about 25,000 hours (slightly more than 2 years). Some exhaust fans, however, can use more than 60 watts as well.

Understanding How Much Electricity Exhaust Fans Use

What Are Exhaust Fans?

An extractor fan and cooker hood extractor in a kitchen
An extractor fan and cooker hood extractor in a kitchen

Exhaust fans are basically small fans that are installed in rooms that don’t offer proper ventilation, such as kitchens and bathrooms to extract odors, fumes, and moisture from the air. This is exactly why they are also known as extractors as well. The function of an exhaust fan is exactly like that of a fan; it blows air out front by sucking the air behind it. This suction is directed with the help of an exhaust fan’s body or vents.

These fans also blow air when they run, but it’s their suction that we find good use of. While the front side of a ceiling fan is the one where it blows air, an exhaust fan blows air toward its back. The electricity usage for an exhaust fan and its efficiency are measured based on the cubic feet of air it replaces per minute (cubic feet per minute, cfm).

Types of Exhaust Fans

Usually, there are two modes on which an exhaust fan operates:

  • Passive exhaust fans that run on low speed, hence utilizing less power. These offer passive ventilation which isn’t as effective but offers much more energy-efficient results. You can run the exhaust 24/7 without having to worry about increased bills.
  • Active exhaust fans that run on high speed, hence utilizing more power. These offer active ventilation which is not as efficient but much more consistent. Running active exhaust fans 24/7 leads to a (slight) reduction in their useful lives. Active ventilation isn’t as gravely impacted by weather effects as passive ventilation.

How Much Electricity Do Exhaust Fans Use?

Bathroom Exhaust Fans

The number of hours you run an exhaust fan, its size, the area it has to ventilate, and its extra features come together to determine how much electricity exhaust fans really use.

There are some exhaust fans that use natural gas, which cost $1.32/therm ($1.32 per 1,000 BTU) or about $0.086 per kWh of use. There are more efficient exhaust fans out there as well that offer as low as $0.013 per kWh under optimum conditions. At the same time, there are larger units that can cost $0.129 or even $0.98 per hour.

Remember, the older your exhaust fan is, the more energy it will consume. This is because as time passes, grime starts to settle between the blades and motor. This is more likely to happen if you don’t use your exhaust fan 24/7. The grime is a mixture of dust and oil. If you have the time to keep your exhaust fan well maintained, you can get away with turning it off when not in use.

Exhaust fans typically use anywhere between 5-35 watts for residential use and can go as high as 60 watts for commercial systems as well. To get an idea of how much that is, a coffee machine uses 75-1,200 watts while a fridge may use anywhere between 50-120 watts. An iron will use anywhere between 800 and 2,000 watts during the normal course of operation.

Kitchen Fans

Kitchen exhaust fans are usually larger and more heavy-duty compared to bathroom exhaust fans since they have to push hot air out – not to mention the odors, scents, and even oil particles in the air! It doesn’t seem like it from the outside, but if you put your finger into a kitchen exhaust, you will understand what it really has to go through.

Kitchen exhaust fans can run from 40 watts all the way up to 90 watts for residential, and 60 watts to 120 watts for commercial use. Residential fans can replace 50 to 140 liters of air per minute, while commercial fans can replace 100 to 350 liters of air per minute.

Running residential kitchen exhaust fans 24/7 isn’t recommended if you are trying to cut down on electrical bills.

Industrial fans, such as the one in our thumbnail, use about 1,200 to 5,000 watts just to start up. However, as they continue running, their cost of operation and electricity usage decreases due to inertia.  

Cost of Running Exhaust Fans 24/7

If you use your exhaust fan 24/7, you can expect to pay anywhere between $0.85 to $23.52 per day, depending on the size and power of your exhaust fan. To give this a little more perspective, an average ceiling fan costs about $1 and 8 cents per day if it runs 24 hours a day at full power.

A major cost that you might have to incur with your exhaust fans is that of exhaust fan repair and maintenance. For smaller, residential exhaust fans that are mostly used in bathrooms, you can expect to directly get the fan replaced when it breaks down. These fans range from $20 all the way to hundreds of dollars. A good quality bathroom exhaust fan should cost you about $50-$70 and will last you 2 years. Most also come with a 2-year warranty, thus minimizing expenses on your end.

As for fans with vents, though, (commercial exhaust fans) repair and maintenance can get a lot more expensive. If you can do it yourself (make sure you know how to safely take the vents off and put them back up after maintenance), you will be saving yourself hundreds, if not thousands, of dollars.

You might not have to replace a vent but the fan itself after about 10 to 15 years. These exhaust fans are long-lived, but because of the increased electricity bill, they aren’t recommended for residential use.

If you are conscious about your electricity bill but don’t want to turn off your exhaust fan, either, we recommend you consider running your exhaust on a lower setting. High-power modes (active ventilation) aren’t just noisy but also present a much more costly alternative to passive ventilation.

Of course, as newer models get released and the ventilation technology gets better and better, high-powered ventilation is becoming more and more silent and cost-effective. For example, Panasonic, Braun, and Mitsubishi are known for their quiet exhaust fans for bathrooms.

Kitchen exhausts, such as range hoods, are relatively noisier with the quietest options being that of Firebird, Z Line, Proline, and KOBE. However, this is just a matter of opinion. Homage, Haier, and Kenwood are also known for their quiet exhaust fans but are more popular in Europe and Asia compared to the US.

As a final measure to help you get a better idea of the wattage figures we explained above, we would like to point out that the average USB fan consumes about 2.5W power per hour.

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About Charlie D Paige

Charlie is a massive DIY fan, with dozens of DIY projects under his belt - ranging from tiling to electrics, and concrete pads to walls. Charlie loves tinkering, seeing how things works, the outdoors and playing with power tools... so is it any wonder that he's completed so many DIY jobs over the years?

Charlie loves spreading his hard-won DIY experience with the world via this blog.