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I’ve got a question that I’m a bit perplexed about and I’m hoping that I can get some comments.
I’ve got a 2850 square foot area where we will be installing an HRV (new contruction). There are 5 bedrooms, a media room, living room and dining room into which we want to push in clean air. For stale air returns, I was wanting to have one in the master bathroom, one in each of our two full bathrooms and one in our powder room. We will also install one at the top of the stairway for the final stale air pickup. We will also install regular (low noise) bathroom fans in each bathroom for those higher use times (bath/shower, smells, etc.).
The HRV contractor told me his supply house guys informed him that if we install stale air pickups into our bathrooms we WILL have smell transfer problems. He was told that WHEN THE HRV IS NOT RUNNING (e.g. summer time, when the HRV is on a 20-minute on – 40-minute off schedule, if the HRV breaks down, etc.), there is a risk of smells from one bathroom traveling to one of the other locations where there is a stale air pickup. When my wife heard this, she became adament that she does NOT want to install any stale air pickups within any of our bathrooms. My concern is that the bathroom air will become stale over time if the bathroom (and regular fan) remain unused and there is NO HRV stale air pickup for that bathroom.
Am I way off base of is the information the contractor received bogus? I asked him and he said that he has never installed stale air pickups into bathrooms for any of his previous jobs. However, he said he would install the system that way if we want it. This is a smart guy when it comes to calculating the installation flow and balancing the system, but I’m look for information from folks with experience having HRV stale air returns within bathrooms or for folks that may know where there may be information about this posted online (at least as far as smell transfers goes)? There is a lot of information saying to have the HRV pickup air from bathrooms, but nothing about a potential for smell transfer if the HRV is NOT running.
My question is this: when the HRV is NOT running, could smells from one bathroom travel within the HRV stale air return lines to somewhere else within the house? Remember, this would ONLY occur if the HRV were NOT running. If it’s running, there really should be no issue as far as I can tell (logically anyway).
There really are only a few times that I could think of during which the HRV might not be running. For example in the summer we will most likely turn it off or put it on a very reduced schedule as my wife likes to open windows and doors for ventilation. Or if it breaks and has not yet been repaired. Other than that, I think we’ll keep it on most of the time or keep it on a 20-minute ON – 40-minute OFF schedule (city requires 8 hours continuous running each day).
All questions or comments welcome!
Thanks,
1BadBoy
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I'm not an HVAC guy, but, Isn't the reason for an HRV due to the lack of air movement in a well insulated home, i.e. no air circulating within the house?, consequently why would you then have odors traveling from one bath to the next when the HRV is not running, wouldn't you be using the bath fans(on timers of course) when you're "on the throne" anyway? and the fans are (will be ) vented separately(from the HRV) to the exterior?
Wouldn't (aren't) the returns set up so as not to allow air flow back to other areas before going to the "recovery area"? or couldn't dampers be used to prevent such from occuring?
just my 2cents worth,
Geoff
Will you have bath exhaust fans in addtion to the stale air pickups? If so, no worries--the stinky bathroom will be de-pressurized whenever its exhaust fan is running, which will prevent odors from escaping.
Additional Information and Comments
Not trying to be a pain to anyone with this post, but once someone tells you this is a possiblity, you begin to wonder. I have no experience, hence this post and these questions.
Regardless of the amount of stink, if it can migrate from one location to another, that's no good! That's the reason for the post and questions.
As for dampers, I was discussing with a friend tonight and this is what we talked about too, so I will definitely bring it up with the contractor as well - makes great sense to me. I think under normal installation, dampers are not typical, but again, I have no experience with it. I just look at forced air systems (non-zoned) and I have never seen one with a damper other than the vent in the bedroom where you can open/close as desired. But I think a damper makes good sense. But when the HRV is not running, the air in the vents becomes static, and hence interior pressure, positive or negative, could cause air in the vents to move (to or away depending on pressure and location).
At this time, we are planning to have exhaust vents as well as stale air pickups in each bathroom, but I've had some folks say to completely forego bathroom dedicated vents and use only the HRV (not too sure about this though). If for no other reason, the vents are a good backup of the HRV breaks or otherwise becomes unusable.
Am I way off base with my concerns? I would probably just go with vents in the bathrooms and dedicated fans too, but my wife is really concerned about odors and transfering, so we're really just trying to get as much information as possible.
Some additional information is that this is new construction within Seattle, WA and the house has no air conditioning (if any of this matters).
Thanks for all the replies and ny other comments or questions are most welcome!
Duplicate Post In Error
Duplicate - how to delete?
Additional Information and Comments
Not trying to be a pain to anyone with this post, but once someone tells you this is a possibility, you begin to wonder. I have no experience, hence this post and these questions.
Regardless of the amount of stink, if it can migrate from one location to another, that's no good! That's the reason for the post and questions.
As for dampers, I was discussing with a friend tonight and this is what we talked about too, so I will definitely bring it up with the contractor as well - makes great sense to me. I think under normal installation, dampers are not typical, but again, I have no experience with it. I just look at forced air systems (non-zoned) and I have never seen one with a damper other than the vent in the bedroom where you can open/close as desired. But I think a damper makes good sense. But when the HRV is not running, the air in the vents becomes static, and hence interior pressure, positive or negative, could cause air in the vents to move (to or away depending on pressure and location).
At this time, we are planning to have dedicated fans as well as stale air pickups [from HRV] in each bathroom, but I've had some folks say to completely forego bathroom dedicated fans and use only the HRV (not too sure about this though). If for no other reason, the vents are a good backup if the HRV breaks or otherwise becomes unusable.
Am I way off base with my concerns? I would probably just go with vents in the bathrooms and dedicated fans too, but my wife is really concerned about odors and transferring, so we're really just trying to get as much information as possible.
Some additional information is that this is new construction within Seattle, WA and the house has no air conditioning (if any of this matters).
Thanks for all the replies and ny other comments or questions are most welcome!
I think this is much ado about nothing, but when SWMBO gets a bee in her bonnet then logic gets thrown out the window.
Dampers on all intakes should be a simple/cheap thing to accomplish and should be enough of a placebo to satisfy her.