ReplyOne on each floor minimum,and a return path from each room,which can e a pass thru,or jumper return.
High or low ,makes little difference in comfort.
Regular Guest
I don't know anything about returns and where they should be ideally. I am adding a forced air system to a 1914 house. All contractos have the same plan for supplies. The are going to run from the basement all the way to the 2nd floor and hit each room from the attic with insulated flex. On the main level they are going to run a main trucnk perpindicular to the joist and take off from the top in the joist spaces and put floor registers where they are needed.
Now when it comes to returns they don't seem to concerned, witch bothers me. Where is the best place for the returns? One contractors plan was to put the ruturns in the ceiling on the second level and floor on the first just like the supplies. Another tried playing me for dumb and said it didn't really matter and was just going to put one off the trunk on the main level and another off the trunk on the second level and that would be fine.
Where will a good contractor tell me the ducts should go on a retrofit?
Banned
One on each floor minimum,and a return path from each room,which can e a pass thru,or jumper return.
High or low ,makes little difference in comfort.
Regular Guest
Whats "pass through" and "Jumper"?
Are returns more a comfort thing or system running well(less problems, more efficent?
So if they give me the option of "fishing" returns up the walls from the basement and down the walls from the attic "but its going to be a lot more labor" is that something I should do if cosmeticly I don't care? Is the floor ceiling set up fine? I guess It thought they were cutting corners cause they didn't want to have to slide stuff up walls.
Banned
Correct return/supply duct and grill size are required,for efficiency and longevity of the eqipment,as well as comfort.
Jumpers are grille in bedroom ceiling,with a large duct,connected to a grille in the common area that has the main return.
Pas thru,grilles back to back,bedroom to common area,using the wall space for air flow.
A way to let the supply air out of the room,so more supply can enter the room.
Regular Guest
dash.... like you more every day... only thing !!!Originally Posted by dash
The biggest thing to keep in mind is T-Stat Placement...
Drag as much air past the T-Stat as possible....
NO!!! Supply's or Returns in any outside/exterior walls !!!
Try to keep as many ducts and jumpers with in the envelope as well... avoid attic if possible.... Pan the floor maybe ???
Regular Guest
I'm lost... so are my contractors correct that it is not worth all the labor to try to get returns into the walls and I should just go in the in the floor for the main level and attic for the second level?
Banned
Yes,those locations should be fine,second floor ceiling is great to remove hot air in heating and cooling.
Eeach room,other the baths and kitchen.needs a return path,for incoming supply air to get back to the ducted return.Could be under the door,if large enough,thrugh the wall,or a jumper return.
Two stories will have more even temps between floors,if you have two systems,zoning,or manual dampers to regulate "seasonal" air flow.
Regular Guest
Convenience is costly and most times inefficient.
Exterior walls are your thermal boundary...
Cramming a metal srackhead into most times 2x4 wall leaving less than an inch from being exposed to extreme temps is crazy.....
#1 lose of energy...
# 2 it is sure to condensate
#3 if a return and not sealed (IMPOSSIBLE with batts !!!) a major cavity void!!
I will try to dig out some of these I have IR'ed .... Most times the entire cavity is glowing !!
Professional Member
I agree with Dash. The best way is with the pass through/jumper grilles. If you have bedrooms that the doors will be closed, this can create an imbalance in the air flow. In most cases, the space under a door does not provide enough return air back to the system.
Regular Member
How large of an under the door gap is enough ....for a typical 30" interior door...to a typical 10 x 12 bedroom?
Key1
Banned
1" in a well insulated home,here in Florida,where the cfm would be around 100.
This will vary drasticlly around the country,depending on the heating and cooling cm required for the "typical" room.
Professional Member
I would design system for climate. Colder you want low wall, hotter you want ceiling. You should have returns in every bedroom and siiting room not in bathrooms, kitchens and laundry rooms. Just using under door will work but not as effective as return in room.
Professional Member
If you go this route, just remember, if you have a high pile carpet, it needs to be 1" from the top of the carpet.
But, again, the best is a return in every room just as 21 degrees mentioned.
Banned
If you have a proper retun path,for all rooms,how are ducted returns better from a comfort or efficiency stand point?
Manual D ,the industry standard,tells us that the location,high or low,of return grilles has little effect on comfort.I know there are several here who disagree.
Professional Member
The critical part is the proper return path from a room with a closed door. What happens if they had a wood floor, then decided a few years later to get carpet, and the 1" clearance went from 1" to 1/4" because of the pile. A pass through grille or a jumper makes sure this isn't affected. The resulting imbalance may cause return air to be pulled from a chimney/bath vent etc.
Am I way off on this?
Professional Member
We all know air takes path of least resistance and I know here in Alberta it is code to have return in everyroom. Using door give you 1" x 36"=36Sq" . We usaully use 8"x14"=112 sq" even if stud space is only 6"x12" still 72" big difference and when you have it right in room you will never have a problem. As far as high and low wall grills I personally think there would be a comfort difference hot air rises cold air falls. I have a 2200 sq' 2 storey and the upstairs was not cooling very good so I installed high wall grills and is better now.
Banned
Change is a valid reason why ducted is better,hadn't thought of that.
Other than a change like that,do you have another reason?
Professional Member
No a valid reason is making it right. If you came in to my house and said we will use under the door for return air. I will show you the door. This is not trailer park ventilation. So dash you are saying that 36SQ" is as good as 72SQ" or 112Sq".
Last edited by 21degrees; 08-02-2008 at 12:54 PM.
Professional Member
None that I can think of. As you said, as long as there is a proper path for the air, it doesn't matter. At least for me.
As far as high vs low returns, if the throw on your supplies is sufficient, it shouldn't matter. But generally in my area, you see high returns on the 2nd floor, because the equipment and/or ductwork is in the attic. On the first floor the duct is in the crawlspace, which means a low return.
Professional Member
I think the assumption was if a 1" space under the door is enough, do you need more? I don't think that more is always better, unless you are talking about the velocity of the air. A larger return from a room would make a difference in noise, and possibly comfort, if it is passing across you.
Last edited by S_Helton; 08-02-2008 at 12:59 PM. Reason: mis-spelling
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