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How many registers? Pic included

Posted by wear_your_baby (My Page) on
Thu, Jun 10, 10 at 23:15

I have some large bedrooms and the HVAC guy has completed his rough-in. I'm quite confused about the number of HVAC registers; it doesn't seem like enough to me. Especially in the two large bedrooms (20x14). In addition to that, I'm wondering if there should be vents it the walk-in closets. Do closets get musty?

There is:
1 register in the right bathroom
1 register in the laundry room
1 register in the kitchen
1 register in the walk-in pantry in the kitchen
1 register under the back window centered in the dining area
2 registers in the living room (1 under each window on each side of the FP)
2 registers on the back end of the left bedroom (we added another window there; they are under each window)
1 register under the vanity in the left side master bathroom
1 register under the window in the center bedroom
1 register in the foyer
1 register in the center bathroom

Floor Plan


Follow-Up Postings:

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RE: How many registers? Pic included

I'll pass on everything but the closets. We have a 10x7 walk-in closet off of the master. The HVAC guys did not feel it needed to have a register, but put one in at our request.

Our closet has two exterior walls, including an unshaded west facing long wall on the gable end of the house. That helped drive our decision.

We found that it works best if we keep it just barely open. Anything else, and it over heats or over cools the closet. Since we have all tile floors, the door undercut easily handles the return air. There is a dedicated return in the master bedroom.

Based upon our experience and the plan you posted, I would say you don't need registers in the closets. I would suggest that if you decide otherwise, make sure there is a return path for the supply air, otherwise you will pressurize the closets.


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RE: Closet Doors

It's hard to tell because of picture size, but I noticed that your plan has small closet doors, roughly 24 inches wide, as far as a I can tell. However there does not appear to be any room for trim.

It looks like the openings, trimmed out, will support only about eighteen inch doors, twenty at the most.

Have you rendered 3D views of those doors from both sides? That will show you how they will look trimmed out.

Just thought I would mention it.


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RE: How many registers? Pic included

At a minimum, interior (mostly interior) walkin closets should have a return air register


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RE: How many registers? Pic included

"At a minimum, interior (mostly interior) walkin closets should have a return air register"

The idea being that the return will draw conditioned air into the closet, I presume. What do you do if there is tight fitting carpet under the door, fit a transfer grill over the door?


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RE: How many registers? Pic included

Just looking through your floorplan, your register count doesn't seem out of sort. But the register count gives us very little information without knowing the size duct going to the registers or the CFM's of air each room is getting. Did your contractor do a room-by-room Manual J load calculation to determine equipment sizing and CFM's required per room? That's really the only way to get it right without using rule of thumb calculations. The walk-in closet in my home has no return or supply register. Keep dust in mind. Not sure if a supply or return in there would make matters better.


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RE: How many registers? Pic included

Just want to send an update. The inspector came through and said we need registers in any walk-in closets that have an exterior wall. This was a good way to solve it! Also, he said he thought the right bedroom should really have one more register, so he requested that or a Manual J to show it was okay. The HVAC guy is adding those 3 vents and I'm pleased with that. He said he can't really add one in the left master b/c there is a TJI under the left wall under the windows, which would make the register quite far from the wall. The return is adjacent to that toilet, so there's no point in putting one on that wall either.

Thanks for your help!


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RE: How many registers? Pic included

"What do you do if there is tight fitting carpet under the door, fit a transfer grill over the door?"

Yes, but ugly, best to cut bottom of door. Doors should'nt rub on the carpet anyways.


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RE: How many registers? Pic included

Make the contractor show you the Manual J for this plan. That is why the building inspector said if the Manual J said 2 registers, that's fine by me. The fact the contractor did not produce the Manual J and caved and said he would put in the extra register, lets me believe he never did a Manual J (and Manual D for duct work) and this is all seat of the pants.


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RE: How many registers? Pic included

It is really difficult to say about your registers because we don't know where you live, do you have heat and a/c through vents. What size registers - they differ by a more than a factor of 2 between small and large. Are they ceiling or floor vents?

If you live in Fl and a/c is a fairly constant thing, then you really want big vents so they are quiet. If you live in the North, have radiant heat, then your needs for air flow are much less.

Which gets back to the manual D and J's that you need. But given that you are too late in the game to deal with shopping for HVAC contractors, I would over vent and pay extra for it if necessary. I have manual D/Js done but not enough vents in my opinion (partly because I have of a zoned system). HVAC contractors (and yours for sure) like to put in a minimum of vents for obvious reasons. I am getting ready to embark on increasing sizes of vents and adding vents to my master bedroom - oh the joy of blown in fiberglass insulation. My house is less than a year old. I am annoyed by the noise and I have a variable speed blower.

Air flow under doors is bare minimum IMO. My doors whistle at high output - I'd do returns in all bedrooms if I had to do it again (and I might add them). Most walk in closets have a vent in my house. The one that doesn't is a bit warm in the summer (east facing single wall with energy star sealing and above code insulation). The walkin pantry with no vent feels a bit cold in the winter (1st floor, single east facing wall). A pantry that is a bit cool is not a bad thing and at least it doesn't get hot in the summer. Neither of these closet issues are enough for me to add a vent - they are small - maybe 5x10. Our master closet has 2 vents but it is bedroom size. We have 2 vents in simlar size master as yours and I'm adding another one.


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RE: How many registers? Pic included

It is really difficult to say about your registers because we don't know where you live, do you have heat and a/c through vents. What size registers - they differ by a more than a factor of 2 between small and large. Are they ceiling or floor vents?

If you live in Fl and a/c is a fairly constant thing, then you really want big vents so they are quiet. If you live in the North, have radiant heat, then your needs for air flow are much less.

Which gets back to the manual D and J's that you need. But given that you are too late in the game to deal with shopping for HVAC contractors, I would over vent and pay extra for it if necessary. I have manual D/Js done but not enough vents in my opinion (partly because I have of a zoned system). HVAC contractors (and yours for sure) like to put in a minimum of vents for obvious reasons. I am getting ready to embark on increasing sizes of vents and adding vents to my master bedroom - oh the joy of blown in fiberglass insulation. My house is less than a year old. I am annoyed by the noise and I have a variable speed blower.

Air flow under doors is bare minimum IMO. My doors whistle at high output - I'd do returns in all bedrooms if I had to do it again (and I might add them). Most walk in closets have a vent in my house. The one that doesn't is a bit warm in the summer (east facing single wall with energy star sealing and above code insulation). The walkin pantry with no vent feels a bit cold in the winter (1st floor, single east facing wall). A pantry that is a bit cool is not a bad thing and at least it doesn't get hot in the summer.


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