Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-14-2011, 04:58 PM   #1
Member
 
Join Date: Jul 2010
Posts: 83
Share |
Default

2 vents off of one duct


Im installing a bathroom in the basement. In the ceiling space, I have a duct supplying heat to the living room above. I was thinking, to get heat into the new bathroom, just cutting into the duct and adding a diffuser (or whatever you call them) to blow into the bathroom.
Obviously I can do this, but is it wise? Will adding a second vent mid-duct mean that all the hot air will exit the first vent (to the bathroom), and basically leave little for the second vent (going upstairs to the living room). OR will both rooms get about equal amounts of heated air?

phantasm72 is offline   Reply With Quote
Old 01-14-2011, 06:33 PM   #2
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,411
Default

2 vents off of one duct


How bad do you want your living room to smell?

beenthere is online now   Reply With Quote
Old 01-14-2011, 07:40 PM   #3
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,838
Default

2 vents off of one duct


If the new register (diffuser) for the bathroom is closer to the furnace than the existing registers, it could drain off a disproportionate share of the warm air from the duct. If you put in an adjustable louvered register, then you could balance the flow.

There are formulas for choosing the size (square inches) of a register cut right in the main duct versus a register at the end of a (lateral) smaller duct extending from the main duct. I don't know these formulas.
__________________
Stop wasting time re-adjusting the pattern. Have several lawn sprinklers, one for each pattern.

Last edited by AllanJ; 01-14-2011 at 07:44 PM.
AllanJ is offline   Reply With Quote
Old 01-14-2011, 07:45 PM   #4
30 year tech
 
hvac122's Avatar
 
Join Date: Dec 2007
Location: Lincoln, Nebraska
Posts: 427
Default

2 vents off of one duct


The heat run for the living room was sized for that area only. It is not a good idea to change that. I would add another vent off of the main trunk line.
hvac122 is offline   Reply With Quote
Old 01-16-2011, 06:25 PM   #5
Member
 
Join Date: Jul 2010
Posts: 83
Default

2 vents off of one duct


Quote:
Originally Posted by beenthere View Post
How bad do you want your living room to smell?
?? this just a joke about 'bathroom' smells wafting up the vents or are you making reference to some serious potential moisture/mould issue?
phantasm72 is offline   Reply With Quote
Old 01-16-2011, 06:35 PM   #6
Member
 
Join Date: Jul 2010
Posts: 83
Default

2 vents off of one duct


Quote:
Originally Posted by hvac122 View Post
The heat run for the living room was sized for that area only. It is not a good idea to change that. I would add another vent off of the main trunk line.
Yeah, I looked at that, but just the way the joists and existing duct work are, its not really possible without significant rearranging of stuff (more than it would be worth). There is another heat vent in the livingroom, and two in the dining room, which is open to the living room. Im not worried about some of the heat being diverted, just not all of it. But I suppose as the above poster mentioned, having an adjustable louvers would limit the air diversion. The bathroom itself I dont expect to be too cold anyways. The basement is well heated and insulated, and the bathroom is going to be pretty much in the middle. I could probably do without, but I thought it would be wise to have heated air going in on days that the shower is used, just to help circulate and remove any moist air and prevent any sort of dampness issues.
phantasm72 is offline   Reply With Quote
Old 01-16-2011, 08:37 PM   #7
Experienced
 
Jackofall1's Avatar
 
Join Date: Dec 2010
Location: Southern Michigan
Posts: 2,822
Default

2 vents off of one duct


Other than the possible drifts of odor from the bathroom the livingroom via the ducting there is nothing wrong with the idea, especially if you add a means of balancing the two amounts of air. If you wanted to keep the volume to the living room you could increase the line size upstream of the new branch, say if it was 6" make it 7" and then add a reducer after the new duct tap.
__________________
When its all said and done there is usually more said than done
Jackofall1 is offline   Reply With Quote
Old 01-16-2011, 09:14 PM   #8
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,411
Default

2 vents off of one duct


Quote:
Originally Posted by phantasm72 View Post
?? this just a joke about 'bathroom' smells wafting up the vents or are you making reference to some serious potential moisture/mould issue?
When the heating system isn't on. those bathroom smells will rise to your living room.
beenthere is online now   Reply With Quote
Old 01-16-2011, 09:16 PM   #9
Experienced
 
Jackofall1's Avatar
 
Join Date: Dec 2010
Location: Southern Michigan
Posts: 2,822
Default

2 vents off of one duct


This is true, drifting odor, unless you have an exhaust fan running.
__________________
When its all said and done there is usually more said than done
Jackofall1 is offline   Reply With Quote
Old 01-16-2011, 09:16 PM   #10
Member
 
sktn77a's Avatar
 
Join Date: May 2009
Location: Chapel Hill, NC
Posts: 259
Default

2 vents off of one duct


Quote:
Originally Posted by AllanJ View Post
If the new register (diffuser) for the bathroom is closer to the furnace than the existing registers, it could drain off a disproportionate share of the warm air from the duct. If you put in an adjustable louvered register, then you could balance the flow.
If you put a damper where you take off from the living room duct, you can adjust the airflow so that you still get adequate air to the living room and some to the bathroom. The advantage of the damper on the takeoff over an adjustable register is that it will be quieter and the air velocity will be lower.
sktn77a is offline   Reply With Quote
Old 01-16-2011, 09:27 PM   #11
30 year tech
 
hvac122's Avatar
 
Join Date: Dec 2007
Location: Lincoln, Nebraska
Posts: 427
Default

2 vents off of one duct


Quote:
Originally Posted by phantasm72
Yeah, I looked at that, but just the way the joists and existing duct work are, its not really possible without significant rearranging of stuff (more than it would be worth). There is another heat vent in the livingroom, and two in the dining room, which is open to the living room. Im not worried about some of the heat being diverted, just not all of it. But I suppose as the above poster mentioned, having an adjustable louvers would limit the air diversion. The bathroom itself I dont expect to be too cold anyways. The basement is well heated and insulated, and the bathroom is going to be pretty much in the middle. I could probably do without, but I thought it would be wise to have heated air going in on days that the shower is used, just to help circulate and remove any moist air and prevent any sort of dampness issues.
Your bathroom exaust fan will remove the moisture and such to the outside. Not sure how heated air will help with moisture.

Usually a basement bath will require a very small btu's to heat so if your not worried about living room then it should be okay.
hvac122 is offline   Reply With Quote
Old 01-16-2011, 09:28 PM   #12
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,411
Default

2 vents off of one duct


And his living room will still smell like his bathroom.
beenthere is online now   Reply With Quote
Old 01-16-2011, 09:38 PM   #13
30 year tech
 
hvac122's Avatar
 
Join Date: Dec 2007
Location: Lincoln, Nebraska
Posts: 427
Default

2 vents off of one duct


Quote:
Originally Posted by beenthere
And his living room will still smell like his bathroom.
Agreed

hvac122 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Planning on New duct work..any feedback... kilosos2 HVAC 28 01-26-2011 09:21 AM
Metal duct or flex? smokey982 HVAC 6 08-06-2010 06:20 AM
Atic: Adding Intake and Exhaust Vents (Maybe Ridge) arcane Roofing/Siding 9 07-22-2010 06:20 PM
Is it ok to put 2 vents on one duct? vetting HVAC 3 02-05-2009 05:40 AM
Condensation in Wall: Can I Seal a Dryer Duct With Caulk? xquercus HVAC 5 07-01-2007 02:33 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.