I am renovating a few rooms including an existing laundry room. It currently has one exterior window and another openable window onto an existing mudroom (which also has exterior windows).

After the renovation, the laundry will lose the exterior window as an existing bathroom is extended. The interior window into the mudroom will survive.

Does the Uniform Building Code require that a room with no exterior windows have an exhaust vent fan? Does the existence of the interior openable window into a room with exterior windows have a bearing on that? (I do realize that local regulations may vary from the Uniform Code, but my jurisdiction generally follows those regs.)

[I know there is a related question here, but I have no air conditioning and I am wondering about the additional interior window.]

  • I'm not sure what the benefit of an exhaust fan in a laundry room would be. Arguably, if it's a gas dryer, an exhaust fan would actually be a bad idea. Interior bathrooms need fans, but that's usually about moisture (or smells).
    – DA01
    Feb 3, 2015 at 3:02
  • It is a gas dryer and there is an open doorway into a hall for airflow. Not advocating, just asking about the rules.
    – bib
    Feb 3, 2015 at 3:09
  • I do not know about the rules, so would have to defer to others. Typically, though, you don't want something competing for air in a room with a combustion appliance unless said vent is the exhaust for the appliance (such as a kitchen hood vent)
    – DA01
    Feb 3, 2015 at 3:11
  • @DA01: I think even if the fan is the exhaust for the equipment, like a hood, if the fan is large enough you have to provide make-up air that is controlled by the fan switch. So that's in addition to any central air vents. Feb 3, 2015 at 4:55

6 Answers 6


No, this is not a code requirement for laundry rooms in dwelling units (at least in the 2012 IBC).

In fact, most dryers are essentially acting as exhaust fans when they run because they take air from the room and exhaust it outside.


Washington State requires a minimum 50 CFM exhaust fan in the laundry room.

  • 1
    Hello, Robert, and welcome to Home Improvement. I edited out your contact info; it's best to put that in your profile. But, with your knowledge and experience, I'm looking forward to more contributions from you. Thanks! Sep 17, 2018 at 19:08
  • 1
    Can you provide a specific citation for this requirement? (It is a curious one, let me put it that way, and the citation to Washington state building code would make this a stronger answer.) Sep 17, 2018 at 23:30
  • See apps.leg.wa.gov/WAC/default.aspx?cite=51-52&full=true for Washington State; search for laundry to find the rules
    – mikeytown2
    Jan 29, 2020 at 7:05

The 2015 IRC (international residential code) requires a 50 cfm fan in the laundry and bath rooms - the exhaust fan is for moisture control

  • This is also true with the UBC Jan 31, 2020 at 0:59
  • Can you give a citation for this in laundry rooms? (As in, which section of the IRC requires this) Jan 31, 2020 at 1:07
  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Jan 31, 2020 at 1:29
  • M15 07.4 Local Exhaust Rates Local exhaust shall be provided in each kitchen, bathroom, water closet, laundry room, indoor swimming pool, spa, and other rooms where water vapor or cooking odor is produced. Local exhaust systems shall be designed to have the capacity to exhaust the minimum air flow rate determined in accordance with Table M1507.4. TABLE M1507.4 MINIMUM REQUIRED LOCAL EXHAUST RATES FOR ONE- AND TWO-FAMILY DWELLINGS AREA TO BE EXHAUSTED EXHAUST RATES Kitchens 100 cfm intermittent or 25 cfm continuous Bathrooms-Toilet echanical exhaust capacity of 50 cfm Feb 6, 2020 at 18:06

Whilst you're specifically asking about the Uniform Building Control, I'll add this as this answers the question for people wanting to know the answer that would be compliant with UK building regulations:

In the UK, utility rooms in newly built homes require either a continuous airflow of 8 litres per second, or a switchable (intermittent) fan capable of at least 30 litres per second. A window alone may not be sufficient to provide this sort of airflow.


As far as I know no active fan is required by code in laundry rooms. Most laundries vent the dryer outdoors which is sufficient to dissipate humidity from the room. Washers generate very little ambient moisture.

However if you intend to vent the dryer indoors then you certainly will need some form of added ventilation to distribute the moisture across a much larger space, probably using a powered fan. Dryers produce even more humidity than do bathrooms, so careful venting is essential.

  • I don't believe code would allow you to vent the dryer indoors in the first place--with our without a vent fan.
    – DA01
    Feb 3, 2015 at 5:11
  • It seems you're right, though some code seems to allow for a special kind of interior dryer vent that condenses the moisture into a special container. homeguides.sfgate.com/…
    – Randy
    Feb 3, 2015 at 5:23
  • And with a gas dryer, those fumes contain more that just moisture...they need to go outside.
    – Grant
    Feb 3, 2015 at 5:26
  • In my case, there is already an exterior vent for the gas dryer that will remain.
    – bib
    Feb 3, 2015 at 12:03
  • 1
    @Randy, That's a special kind of dryer (a condensing dryer), not a special kind of vent. Feb 3, 2015 at 15:52

Exhaust fans in laundry rooms are usually required when there is no exterior window in the room and the dryer to be used heats with gas power. Why? To exhaust the carbon monoxide (CO).

CO in large amounts is hazardous to humans and can cause asphyxiation/death.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.