Can I Use a Bathroom Exhaust Fan in The Kitchen? How Different are Those?

There are no known codes for using an exhaust fan in the kitchen, but installing one will be a useful addition to keeping the air in your kitchen clean and fresh. Think about it, the grease, smoke and odor from all the cooking can pile up and make breathing in the kitchen unpleasant.

In many cases, leaving your kitchen windows open may help, but when the situation becomes severe, an exhaust fan may just be the extra hand you need to keep things in check.

That said, are all exhaust fans the same? Can they all be used for all applications? We’d really doubt that.

So, if you’re wondering whether a bathroom exhaust fan can be used in a kitchen, we’ll help you break all of that down in a way that you’ll understand. Let’s get right into it.

Can You Use a Bathroom Exhaust Fan in The Kitchen?

No, you should not use a bathroom exhaust fan in the kitchen. In fact, if you buy an exhaust fan designed for bathrooms, it is often indicated that it should not be used in kitchens.

Bathroom exhaust fans are not built to withstand the heat of the kitchen; they do not have filters and are also not beefy enough to remove grease. The only time you should use a bathroom exhaust fan in a kitchen is if you simply want to waste your time and money.

Another factor to consider is that most bathroom fans have a CFM rating of between 50 and 130. Bathrooms larger than 100 sq ft with multiple fixtures will probably be rated for 150 to 200 CFM.

However, a good exhaust fan for a kitchen should be rated above 300 CFM because a lot of air exchanges are needed in a kitchen. So, a bathroom exhaust fan won’t have much effect in a kitchen, especially one that requires adequate ventilation.

It is always best to have exhaust fans in rooms where they are specifically designed to be installed. Besides, a typical kitchen exhaust fan would use a 6-inch duct or larger and the size of the stove is a factor you must consider at all times.

For example, this Cosmo Wall-Mount Kitchen Ducted Exhaust fan is rated 380 CFM, while a typical bathroom exhaust fan like the Broan-Nutone AE110 Energy Star unit is rated 110 CFM.

Can Kitchen and Bathroom Exhaust Be Combined?

The simple answer is No. Not only is it against model mechanical codes, it is also largely impractical and unrealistic to achieve any good result by that action.

Section 505 of the International Mechanical Code, covering domestic kitchen exhaust equipment, clearly states that the duct of a kitchen exhaust must be independent and separate from every other exhaust system.

The exhaust fan system of a kitchen needs to be built for greasy exhaust, and there’s also talk of a fire risk in the kitchen exhaust fan duct as they’re hardly ever cleaned, but this is largely untrue.

Also, it is unlikely that the fan in the bathroom is of equal power to that in the kitchen. Where one fan overpowers the other, you can have a situation where one fan sends the waste from one room to another.

We can guess that the kitchen fan is more powerful; hence, you’d have to deal with kitchen fumes in your bathroom.

Bathroom Exhaust Fan Vs Kitchen Fan [Key Differences]

There are certain differences to take note of as far as kitchen and bathroom exhaust fans are concerned. We’ve already mentioned a few of them casually in previous sections of this post, but it’ll make more sense to itemize them properly for your benefit.

1. Size/Strength

Beyond CFM rating, kitchen exhaust fans also tend to be larger and stronger. On average, they require a duct between 6 and 9 inches, while a bathroom exhaust fan would usually need a duct less than 6 inches.

As for strength, kitchen fans need to be able to remove gaseous, liquid, and sometimes oily wastes as well. Meanwhile, a bathroom exhaust fan is only needed to remove odors and vapor.

2. Filter

A kitchen exhaust fan also normally has a filter fitted into it to prevent dust particles from coming in from outside in the process of air exchange, whereas a bathroom exhaust fan doesn’t feature a filter.

3. Heat/Grease

Kitchen exhaust fans (sometimes called a range hood) are designed to remove heat and grease along with other air particles and odor.

On the flipside, bathroom fans do not have such capacity for removing heat and grease, at least not the type and amount produced in the kitchen.

4. Price

Obviously, kitchen exhaust fans are largely more expensive due to their enhanced features and rating. In fact, in many cases, kitchen fans are twice the price of bathroom fans designed for the same square footage.

This doesn’t mean one can substitute the other though because they serve specific purposes beyond general ventilation.

5. Rating

This is one of the most obvious differences between a bathroom exhaust fan and a kitchen exhaust fan. A typical bathroom fan is rated between 50 and 130 CFM, except those designed for really large bathrooms larger than 100 sq ft.

On the other hand, an average kitchen exhaust fan would have a rating of more than 300 CFM. This is because kitchen fans need to be faster to quickly deal with all the pollutants they’re meant to handle.

Final Words:

One final thing to note is that these fans need to be vented through a duct and outside the house, so you don’t have pollutants and bad air piling up in your ceiling.

These fans obviously look the same and, quite frankly, it may be difficult to tell one from the other if you’re not knowledgeable in ventilation systems. But, that doesn’t mean you can substitute one for the other.

Do not use bathroom fans for the kitchen because it will just be a waste of money and effort. If you need an exhaust fan for your kitchen, make sure you buy one designed for the kitchen.