# Building HVAC vent into bath vanity



## nolamar (Jan 10, 2011)

I'm remodeling 2 bathrooms, well, I hired a great contractor to do all the things I don't know how to do. Anyway, for the hall bath, they suggested moving the floor vent to the toekick of the 48" vanity. I thought this is a great idea since the floor vent is in an odd location. My mother has louvered vents in the toekicks of her vanities and they work great.

My question is this: Shouldn't it be venting directly to the new register under the vanity instead of just blowing the air under the entire vanity?

The reason I ask is that I just found out today that they are planning on having the air flowing under the whole vanity and not directly to the register in the toekick. I would have never agreed to this arrangement if I thought it was going to be done this way. They have already repositioned the old floor vent to open up under the vanity bottom, but the vanity has not been cut yet to accomodate a register and the vanity won't be reinstalled for at least another couple weeks.

Any thoughts on this and ideas of standard practices in this situation?

I attached a pic of the vanity before they removed it.

Thanks!

Mary N.


----------



## Ron6519 (Mar 28, 2007)

The duct should be extended to the front of the toe kick so the heat reaches the room, not trapped under the vanity to find it's way out willy nilly.
Ron


----------



## nolamar (Jan 10, 2011)

Ron6519 said:


> The duct should be extended to the front of the toe kick so the heat reaches the room, not trapped under the vanity to find it's way out willy nilly.
> Ron


Thank you, Ron, for the reply. I totally agree with you. :yes:

While these guys are good, I still have my own vision of what is right to do, and I am always surprised to find out that the pros sometimes do things in a questionable (at least to me) manner. I have to research everything and ask questions relentlessly, never assuming. It's an amazing learning process. Thank you.

Mary


----------



## COLDIRON (Mar 15, 2009)

Ron6519 said:


> The duct should be extended to the front of the toe kick so the heat reaches the room, not trapped under the vanity to find it's way out willy nilly.
> Ron


":thumbsup::thumbsup::thumbsup::yes::yes:


----------



## SPS-1 (Oct 21, 2008)

Let's see if I understand this:
You say the air should be ducted all the way to the toe-kick.
They plan on straight up under the center of the vanity, stopping the duct at the floor. 
As long as they also plan on on putting louvers on the front of the toe-kck, for the air to exit, I don't see what the problem is.

And don't get mad at the contractor. I have yet to read a valid reason on this post as to why it shouldn't be done that way.


----------



## COLDIRON (Mar 15, 2009)

SPS-1 said:


> Let's see if I understand this:
> You say the air should be ducted all the way to the toe-kick.
> They plan on straight up under the center of the vanity, stopping the duct at the floor.
> As long as they also plan on on putting louvers on the front of the toe-kck, for the air to exit, I don't see what the problem is.
> ...


Duh!!!!!! Whaaaaaaatttttt????????


----------



## nolamar (Jan 10, 2011)

SPS-1 said:


> Let's see if I understand this:
> You say the air should be ducted all the way to the toe-kick.
> They plan on straight up under the center of the vanity, stopping the duct at the floor.
> As long as they also plan on on putting louvers on the front of the toe-kck, for the air to exit, I don't see what the problem is.
> ...


I need to clarify that I am in no way mad at the contractor and I don't know where you picked that up, LOL! I like them and keep paying them to come back and work on the house. Just so we're perfectly clear on that.

I've researched this particular scenario and while responses overall around the net are mixed, they do tend to favor a direct venting to the toekick rather than the hot/cold air just hovering within a 48x22x4 space.

A point that I left out in my first post is that the plumbing comes up through the floor from the crawlspace rather than the typical wall installation. So there is some concern about the air, if not directed properly, either going back down into the crawl or just coming out under any of the four sides of the vanity, including the side against the wall. We could make the argument that they could seal any gaps around the plumbing of course.

I don't plan to caulk the entire bottom edge to the new floor or the edge against the wall (to seal it) as that doesn't seem necessary or even common practice. So my favored method is to direct the airflow out the front vent to get the most air possible into the bathroom.

The new floor vent (4x10) is positioned very near the left side and about 10" from the wall, midpoint from front to back. The green in the attached photo is the wall behind the vanity. Just interested to hear about methods others have used to accomplish my vision and if its feasible. I believe a duct can be constructed to fit within a 4" tall space and exit out the front.

I'm an optimist! :laughing:

Thanks,

Mary


----------



## bob22 (May 28, 2008)

I think as the customer you get what you want since you are paying the bill. Tell him/her that you want it ducted to the toe-kick and not into the base of vanity. This is not rocket science nor an unreasonable request.


----------



## ubenhad4 (Jan 13, 2011)

Ive never seen it routed to the vent. The cabniet base acts as a duct and the louvers release the air into the room. Where do you think the air is going under the cabniet? I do not understand why you would want duct ran to the face its doing the same thing.

Back before fire code got so strict the hvac returns would be a stud bay that was plyed in and sealed. Sometimes main supplies would run like this floor to floor to. Nothing wrong with it except it allowed fires to race up through the building. The toe kick works the same way. This is industry standard so expect an extra charge if you have them run duct.


----------



## nolamar (Jan 10, 2011)

Ubenhad4 wrote: _Where do you think the air is going under the cabniet? I do not understand why you would want duct ran to the face its doing the same thing.

_I don't think the air would do the same thing in a 48x22 space. I think that the air under the cabinet is going to go into the cabinet for starters, being that the plumbing comes up through holes in the vanity base. As well as the other places I mentioned in my above posts. I never considered that this might be a fire hazard, first time I've heard of that reason.:huh:

This is certainly an interesting topic to me, with hardly any real reasons given to not do it, but I'm not convinced yet that a duct connected to toekick is wrong or unreasonable. Keep 'em coming.

Thanks,

Mary


----------



## ubenhad4 (Jan 13, 2011)

nolamar said:


> Ubenhad4 wrote: _Where do you think the air is going under the cabniet? I do not understand why you would want duct ran to the face its doing the same thing._
> 
> I don't think the air would do the same thing in a 48x22 space. I think that the air under the cabinet is going to go into the cabinet for starters, being that the plumbing comes up through holes in the vanity base. As well as the other places I mentioned in my above posts. I never considered that this might be a fire hazard, first time I've heard of that reason.:huh:
> 
> ...


 I never said its a fire hazard. I has talking about old chases in older houses. Not a toe kick vent. Your plumbing penetrations from floor to floor should have been foamed by the insulator. If your plumbing runs up through the bottom and your worried about the small air lose throught the trim rings for the pipes just seal those. The size of the chase being larger is no problem the air is forced air so it will not just hang out under the cab. It will take the path of least resistence that being the toe kick vent. 

Your other concern is no concern at all. Your worried about losing air to the side of the cab thats installed in the same room your toe kick vent is in. Why are you worried if the air is coming up the side of the cab? Its still entering the room. All vent in my kitchen and baths are toe kicks set up like your hvac guy has them. There might be a little air being blown into the cab but its not air tight and leaks into the room. I dont open a cab door and it feels warmer in there. I think your over thinking this and just going to cause un needed friction between you and the hvac installer over a non issue.

The reason not to do it is it is not needed and not industry standard. It gains you nothing. The same amount of air is entering the room.


----------



## nolamar (Jan 10, 2011)

Ubenhad4...I never gave thought that I should call in my "insulator" after the plumber left today to foam the lines the plumber just replaced.

All these pesky details! Where's my yellow pages? :jester: Thanks.


----------



## COLDIRON (Mar 15, 2009)

As mentioned previously install the duct to the toe kick, nobody runs ducts to nowhere it's just plane stupid. You might have to transition that duct from 10 x 4 say to 12x3 or 14 x3 to get a diffuser to fit properly under the kick. NOTE: as mentioned previously regarding return air installation using the walls as duct that is standard in the industry there's no pressure on the return air like there is on the supply.


----------



## ubenhad4 (Jan 13, 2011)

COLDIRON said:


> As mentioned previously install the duct to the toe kick, nobody runs ducts to nowhere it's just plane stupid. You might have to transition that duct from 10 x 4 say to 12x3 or 14 x3 to get a diffuser to fit properly under the kick. NOTE: as mentioned previously regarding return air installation using the walls as duct that is standard in the industry there's no pressure on the return air like there is on the supply.


 First off your wrong. Industry standard is to terminate at the floor and the cab acts as the duct. I have never seen it any other way and I have worked around at least two dozen different HVAC companies. The duct isnt ran to nowhere its ran into the room. The cab directs the airflow. The diffuser for toe kicks is either slots cut into the toe kick or just the grate attached to the front. I dont understand why someone would want to spend time and money on something that just doesnt matter performance wise. 
Second place your wrong is on the return. There is negative preassure in the return, how to you think the air get from the grill to the unit? The same pressure thats blown out of the unit has to be sucked in. The blower unit does not make air it cycles air from the return out the supply vents. Please dont give people miss information so that they go get into it with the contractor when hes doing nothing wrong.


----------



## ubenhad4 (Jan 13, 2011)

nolamar said:


> Ubenhad4...I never gave thought that I should call in my "insulator" after the plumber left today to foam the lines the plumber just replaced.
> 
> All these pesky details! Where's my yellow pages? :jester: Thanks.


 All penetrations have to be sealed at floors, ceilings, and attic. This takes care of you air leak concern, as well as fire code. Seal it up install the vanity, cut the toe kick for the vent and your done. The cool part about running it under the cab is it will warm the floor up. If you make a few hole on the side that faces the toilet it will keep the toilet toasty to.


----------



## COLDIRON (Mar 15, 2009)

U BEEN HAD 4 Sorry you are wrong all supply ducts terminate with a register boot and diffuser. That's That. You can ramble on all you want but you are totally wrong. Think about it what if you did that throughout the house the air wouldn't know which way to , you have to direct hot and cold air where you want it to go , IE: In front of windows, doors, openings. Duh!!!!!! I would never just cut a hole in a vanity and pump hot air in there it has to go out to the room. Glad I do all my own work and don't have to call in Contractor's if that's what I get.


----------



## Jackofall1 (Dec 5, 2010)

ubenhad4 said:


> All penetrations have to be sealed at floors, ceilings, and attic. This takes care of you air leak concern, as well as fire code. Seal it up install the vanity, cut the toe kick for the vent and your done. The cool part about running it under the cab is it will warm the floor up. If you make a few hole on the side that faces the toilet it will keep the toilet toasty to.


Have done, will do it again and again, no duct required, cabinet base acts as a plenum.


----------



## COLDIRON (Mar 15, 2009)

You guys crack me up. You sound like Mechanical Engineers or Homebuilders. Thank God I do my own ductwork.


----------



## ubenhad4 (Jan 13, 2011)

COLDIRON said:


> You guys crack me up. You sound like Mechanical Engineers or Homebuilders. Thank God I do my own ductwork.


 DIY guys crack me up. Here one of you guys ask a question, It get answered by PRO contractors and you say where wrong. The air goes out from under the cabniet through the register slots in the toe kick as I explained earlier. They dont just leave the duct buried. The air travels out exactly as it would if it was ducted over to a whole as the under cab cavity acts just like a duct and the air goes out the register in the front.:thumbsup:. Everyhouse I have ever built or worked on is like this for toe kick heat, its like this for kitchens, baths, and laundry rooms.


----------



## ubenhad4 (Jan 13, 2011)

COLDIRON said:


> U BEEN HAD 4 Sorry you are wrong all supply ducts terminate with a register boot and diffuser. That's That. You can ramble on all you want but you are totally wrong. Think about it what if you did that throughout the house the air wouldn't know which way to , you have to direct hot and cold air where you want it to go , IE: In front of windows, doors, openings. Duh!!!!!! I would never just cut a hole in a vanity and pump hot air in there it has to go out to the room. Glad I do all my own work and don't have to call in Contractor's if that's what I get.


 I have four toe kick resisters in my own home and the air all comes out just as hard as at the floor registers. Saying it doesnt is like saying ceiling mounted registers dont heat as well as floor mounted ones. Oh and also you dont ever run a register infront of a door or an opening.

Duh Huh... wow please do your own work and leave the contractors in peace you obviously know more.


----------



## COLDIRON (Mar 15, 2009)

I quit every body just do it the best way they know how. Coldiron out.


----------



## mjzraz (Jun 28, 2008)

*If it were my house...*

If it were my house, I would want it ducted to the opening. What $5 in materials and 5-10 min work? It just seems lazy to do it the other way. Saves time, sure, but I personally wouldn't want my cabinet subjected to hourly cooling and heating cycles. 
In the real world does it pose a problem? Probably not. It's probably not that big a deal, but as a consumer paying for work done, the perception is that he's sloppy, lazy and cutting corners wherever he can. I would want my contractor to say:
"We usually don't duct it and it's fine, but if you want it ducted, we can do it, it's $XX extra "


----------



## Michael Thomas (Jan 27, 2008)

We had a long discussion of this over on inspection news: http://www.inspectionnews.net/home_...al-inspection/17969-furnace-ducting-work.html


----------



## mjzraz (Jun 28, 2008)

Michael Thomas said:


> We had a long discussion of this over on inspection news: http://www.inspectionnews.net/home_...al-inspection/17969-furnace-ducting-work.html


Looks like the spirit of the code would dictate ducting to the face of the vanity as the vanity itself would be considered part of the supply plenum. 

The technical interpretation (aka half @ss interpretation) would be to install a difuser vent under the cabinet and call it to code.


----------



## nolamar (Jan 10, 2011)

*Building HVAC vent into bath vanity UPDATE*

I agree with mjzraz and a few others here, especially Coldiron, who relentlessly weighed in on my topic.

While they tried to talk me out of it with comments like "It's not usually done this way" and my response of, "I KNOW how some people tend to do it"...I stood my ground and I got what I wanted. The air is vented directly to the toekick, my way. :laughing:

Thanks to all for the input. This was one hot topic! Geez.

Mary






mjzraz said:


> If it were my house, I would want it ducted to the opening. What $5 in materials and 5-10 min work? It just seems lazy to do it the other way. Saves time, sure, but I personally wouldn't want my cabinet subjected to hourly cooling and heating cycles.
> In the real world does it pose a problem? Probably not. It's probably not that big a deal, but as a consumer paying for work done, the perception is that he's sloppy, lazy and cutting corners wherever he can. I would want my contractor to say:
> "We usually don't duct it and it's fine, but if you want it ducted, we can do it, it's $XX extra "


----------



## COLDIRON (Mar 15, 2009)

I thought this subject was long gone and was tired of the so called experts and didn't want to argue with them any more. Good job nolamar your vent came out exactly as I thought it would and it looks real good and PRO.

Signed COLDIRON
40 YEAR HVAC PRO semi retired.

PS: Good decision and thanks for getting back to us.


----------



## HOTINTN (Aug 5, 2010)

*Mold under cabinet*

I have a 1987 house in the Nashville TN area. Very humid. I am presently spending a few days cutting the bottoms out of a 1/2 bath cabinet and a kitchen cabinet, as the vent stopped at the subfloor and used the cabinet base as a plenum causing a large amount of mold. I am having to add toekick plenum boxes to eliminate the problem. I will mention that my HVAC guy suggested using foamboard under the sheetmetal plenum and using insulation on the top and sides. You, no doubt, saved yourself some serious mold issues in the future.


----------



## Red Squirrel (Jun 29, 2009)

+1 for ducting it directly, which I see has been done. 

The base could have acted as a plenum, but that's like putting a 5 inch round hole in a wall going to another room, closing the door to that room, and saying that the room acts as a plenum so you don't have to run a duct to the other room. :laughing:

Having a large cavity of space like that will add static pressure and turbulance, and the flow rate won't be as high as it could be. 

And yes, mold, especially in humid areas, or if you use a humidifier in winter. You only get one shot at this, once that vanity is down, it's over, unless you want to be ripping appart plumbing and stuff later because of a funny smell. :laughing:


----------



## rubberhead (Mar 3, 2011)

nolamar said:


> I agree with mjzraz and a few others here, especially Coldiron, who relentlessly weighed in on my topic.
> 
> While they tried to talk me out of it with comments like "It's not usually done this way" and my response of, "I KNOW how some people tend to do it"...I stood my ground and I got what I wanted. The air is vented directly to the toekick, my way. :laughing:
> 
> ...


Oh my god, that is the finished product?


----------



## nolamar (Jan 10, 2011)

rubberhead said:


> Oh my god, that is the finished product?


Why yes it is, rubberhead and what is your opinion. It's the photo posted in post #25, although a bit orangey in tonality. The toekick vent works great! :thumbsup:

Although, they had the tile guy do it rather than an HVAC person. I would have preferred that the seams be taped up but "shrug" when MOST men are working with a woman, they wanna talk us out of everything sensible.

Basically though, I got what I wanted, not what they -didn't- want to do.

Thanks for reviving this old thread (sarcasm). What a nightmare it was. :huh:

Mary


----------



## COLDIRON (Mar 15, 2009)

Hey Rubber is that sarcastic or is it a compliment ? it's hard to tell sometimes. Nice looking functional job HUH?

"NO MOLD"


----------



## picflight (Aug 25, 2011)

It is more efficient to duct it to the toe-kick just as you did, I would have done it the same way.


----------



## Batdude2 (Feb 11, 2018)

We recently moved in to a newer home. It didn't take my wife too long, once winter came, to realize everything in the vanitys were literally cooking. Since we have never encountered such a thing I looked into it. Sure enough the duct simply pours heat into the cavity under the cabinet and it acts like a plenum. THAT'S INSANE PEOPLE! Its cooking the supplies and liquids in the cabinet! My solution was to use some thermal cardboard and thermal duct tape to route the air to the front vent. I purposely have it leaking on the sides just a tiny bit as this is an outside wall and the water pipes run through there (not that it's any concern at all). It worked great. No more cooked Listerine. Lol.


----------



## Marson (Jan 26, 2018)

Funny, I used to build affordable housing in Minnesota, and the HVAC guys always ducted the heat runs to the front of the cabinet. Then I move out west and am working on million dollar houses and all I see is the heat punched into the bottom of the cabinet with a register into the toekick. I'd duct it myself.


----------



## joellewis (Feb 11, 2018)

I would duct as well.
Here’s a kit that that looks like a very simple solution.
http://toekickductor.com


----------



## batdude (Jan 4, 2011)

joellewis said:


> I would duct as well.
> Here’s a kit that that looks like a very simple solution.
> http://toekickductor.com


Yes, that's a nice solution. In my case though I cannot remove the cabinet and its not easy to work under there through the small toe-kick hole, so a piece of thermal cardboard cut to snug width worked great. Simply angle it down to the floor to force all the air out the front toe-kick register. :smile:


----------

