Basement bath and the HPWH

JakeCK

I'm almost done remodeling my basement bath and I had the thought of getting the duct kit for my water heater and ducting the supply air in from the bath. The idea being that shortly after starting the shower it would begin to draw the much warmer, moist air from the hot shower. This would be very easy since the water heater is right on the other side of the wall from the shower.

My only concern is if the hpwh can condense enough of the moisture to prevent an issue in the much cooler laundry room where it exhausts to? And if it might cause an issue with the exhaust fan? Maybe a transfer grill up by the ceiling between the other rooms and bath?

Thoughts?

pecmsg

Interesting Idea.

Yes, you will probably see some condensation, but the HPWH should lower the dew point enough so it's not an issue.

Try it and let us know.

ethicalpaul

My prediction: any benefit would be immeasurably small

Mad Dog_2

I'd worry about stacchibotrus (spelling?).  Black mold.  I've seen that when guys take the short cut of not punching a bathroom exhaust fan through to the outdoor air and just vent in to an attic or crawlspace Mad 🐕 Dog

ChrisJ

@JakeCK
Interesting idea, but, why not pipe the WH outside as well? If there's doubts in flow, add a good Panasonic 3 speed fan to the bathroom for good measure and pick the speed you need.

Besides,
Who wants poop fumes in the basement.

JakeCK

@Mad Dog_2 There is an exhaust fan to the outside, I had to double check but I did mention that. I specifically was wondering if the negative pressure created by the hpwh would affect the exhaust fan when both are running. I'm going to have the exhaust fan controlled by a humidistat as well. 

I'm not worried about moisture in the bathroom, its the utility room I was wondering about. 

That said the hpwh shouldn't be running much while someone is dropping a loaf unless you drop em' while taking a shower. :S

:smile:

The idea isn't to use the hpwh to replace having the code required exhaust fan! The idea is to just have the hpwh pull the air from the bathroom.

ChrisJ

JakeCK said:

@Mad Dog_2 There is an exhaust fan to the outside, I had to double check but I did mention that. I specifically was wondering if the negative pressure created by the hpwh would affect the exhaust fan when both are running. I'm going to have the exhaust fan controlled by a humidistat as well. 

I'm not worried about moisture in the bathroom, its the utility room I was wondering about. 

That said the hpwh shouldn't be running much while someone is dropping a loaf unless you drop em' while taking a shower. :S

:smile:

The idea isn't to use the hpwh to replace having the code required exhaust fan! The idea is to just have the hpwh pull the air from the bathroom.

I don't know how your household works but in mine there's two bathrooms, either can have a deuce dropped while the other is in use. There's also a dishwasher and clothes washer that consume plenty of hot water. In theory the water heater would likely be going while people are Rollin' Kohler in both bathrooms.

I like the Panasonic fans, I just wish there was a way to wire a wall switch for high and low.

JakeCK

This is the third bath, technically a 3/4 bath. 1 full upstairs, 1 half downstairs, and then this basement bath.

My water heater only runs maybe 3-4 hours a day, much longer on a high usage day(multiple loads of laundry). 5 hours today with a couple showers and a single load of laundry. But yes if someone takes a #2 while the hpwh is running there is a chance you might smell something in the laundry room adjacent to it. But this bathroom is going to see very light usage compared to the other bathrooms. It is the bath for my man cave. I even had the fleeting thought of putting a urinal in there.

I just wish one didn't have to walk though my man cave to get to the laundry room...