23

I just found out that our bathroom exhaust fan has no duct attached to it. Our current fan is Panasonic FV-08VQ2 (90 CFM, 4" duct diameter). The fan just blows the air to the inaccessible attic. There is what looks like an attic exhaust close to the location of the fan but no duct (see white circle in the picture). The bathroom exhaust fan is about 5' from the window on the top floor. Here are my questions:

  1. Is this a big problem? I assume the fan has been like this for 15+ years. If it is, I will look into getting a duct there, which is complicated by the inaccessible attic space.

  2. Should we stop using the fan until this gets fixed?

  3. Should we be concerned about any mold etc in the attic as a consequence of this?

Thanks!

enter image description here

user2503795
  • 831
  • 3
  • 8
  • 20

5 Answers5

35

Is this a big problem? I assume the fan has been like this for 15+ > years. If it is, I will look into getting a duct there, which is complicated by the inaccessible attic space.

Moisture in the attic is a problem and the fan needs to be ducted to the exterior. I find it hard to believe that your attic has no access. Code requires one for many reasons including maintenance and for fire fighting.

Should we stop using the fan until this gets fixed?

After 15 years, a little longer won't be a big difference in the overall picture and not using it can cause problems in your bathroom due to excessive moisture there.

Should we be concerned about any mold etc in the attic as a consequence of this?

Yes. When you get the work done have them check for mold and decay of the roof framing members and roof sheathing

Ack
  • 5,759
  • 4
  • 21
  • 32
7

Venting into an attic is terrible in North American climate zones (6,7,8 in linked map below); less so in arid southern zones (1,2). This will give you a sense of how bad this might be. Beyond that, what @ack said.

Map: zone map

Aloysius Defenestrate
  • 23,521
  • 1
  • 33
  • 61
7

Ack's answer is very good, so I won't repeat what they wrote.

I will add that molds can definitely create a significant health hazard.

I would get the attic inspected for the presence of hazardous levels of molds.

From personal experience, I can tell you that mold inside walls and attics can be extremely hazardous to your health. It doesn't have to be visible within the rooms of your home. Having mold inside walls, attics, or crawl spaces is more than sufficient to cause years of serious health problems and needless suffering.

Add effective ducting and test for mold.

Amazon Dies In Darkness
  • 2,749
  • 11
  • 45
  • 70
1

As already stated this is bad for your attic and underside of roof, when you do install ducting make sure it is insulated.

Anthony Johnson
  • 11
  • 2
0

New exhaust vent shall be located at least 4 feet from a window opening as per nsbc. Unless your unit has a sprinkler system. I would redirect through the roof with a duraflo exhaust vent.

Daniel Griscom
  • 6,319
  • 33
  • 33
  • 43
user115361
  • 1