How to ventilate bathroom

I bought a house last fall (built in '93) that has a bathroom in the lower level (split level so 1/2 below and 1/2 above ground) with no HVAC to it - there is neither a vent into the bathroom nor an exhaust fan. The room also has no outside walls as someone built a sunroom onto the back of the house.

So, I know I need to get some conditioned air flowing into this room and exhaust the humidity but I'm a little short on ideas. While the utility room is adjacent, the walls were built such that I can't really get to the vent trunk from inside the utility room but I could if I cut the wall between it and the bathroom.

Given that exhausting to the outside would be difficult, my thought has been to cut a couple vents connecting the bathroom to the utility room to at least allow a little air to move passively. There is a dehumidifier in the utility room so I thought that might help a little in the summer.

Any better/good ideas?

 

I have two closets that are vented between them. That's not enough for a bathroom. What's directly above the utility room & bathroom?

 

Another bathroom is above the bathroom, kitchen is above the utility room.

 

Does the kitchen or utility room have an outside wall?

 

Part of the utility room wall is outside, part is covered by the sunroom. Kitchen has an outside wall.

 

Have you considered using a wall mounted vent fan in the bathroom and constructing a chase to run a duct through the utility room and outside?

My other suggestion would have been to vent up into a kitchen cabinet and then run the duct in the cabinets to the outside.

 

I thought of a wall mounted fan earlier today but not of running a chase through the utility room to the outside. Beats anything I've come up with thus far, thanks.

 

What kind of ventilation does the bathroom on top have? If it has an exhaust fan, install a vent between the two bathrooms & install a 3 way switch in each to start & stop the fan.

 

Yes, upstairs bathroom does have an exhaust fan.

Thank you, gentlemen - I now have some decent options to consider.

 

OK, I'm on another track looking to see whether the rest of you think this is a good or bad idea or any type of code violation.

So, after more looking, I realized there's a duct from the furnace in the ceiling above the shower. If I were to cut a vent into it, there would be a source of air into the bathroom in exactly the spot I would want. I'm aware I would be pushing the humid air into the rest of the house from the bathroom but am comfortable that the AC and dehumidifier will be able to handle that in the summer and the house is pretty darn dry in the winter so no worries there. Beyond that, the only downside I'm seeing is the potential for the AC to be blowing on someone while they're trying to take a shower but it's really only me who uses that one and I could close the vent while the shower was in use.

Comments/critique?

 

Hi, not sure how the bathroom is used, but my bathrooms need venting because of moisture AND odors. I wouldn't want to push the air from my bathroom into the rest of the house! Good luck, Steve