Another return question

[ampulman]

In the thread, Carrier vs. Am. Std., Robotec said:

"If your supply registers are on the floor or low on the wall, then a ceiling return would be best."

I also have a lack of return upstairs, especially with doors closed. In two bedrooms, I have a wall which is shared with the stairswell. Has it ever been done where a return grill would be cut in on the wall at the ceiling in the bedroom, then a similar grill placed at a lower level on the stairwell side? These would be located between studs.

The location of the grills in the stairwell would favor the downstairs return grills, where there are 4, vs. 1 upstairs.

Amp

[hivacer]

Do you mean just like a transfer grille where you put grille on either side of the wall to let the air into the hallway?

You can do this, it is best to cut the one in the bedroom high and the on in the hall low to for privacy, but the wall stud cavity has to be open of course in between.

[beenthere]

Probably do more harm then good.

When the A/C shut off. It would have a chimney effect. And let the first floor heat rise into those rooms. making them worst then before.

May also violate code.

Since in a fire. The fire would be able to travel though that wall chase from the first floor to those second floor rooms even with the doors closed.

[ampulman]

Do you mean just like a transfer grille where you put grille on either side of the wall to let the air into the hallway?

You can do this, it is best to cut the one in the bedroom high and the on in the hall low to for privacy, but the wall stud cavity has to be open of course in between.

Yes, that is exactly what I mean.

I'm looking at 'creative' ways to handle the other two bedrooms, other than over the doors.

Amp

[dash]

Manual D says ,return location high or low has little effect on comfort,believe it or not.

[Brian GC]

....believe it or not.

NOT !!!

[ampulman]

Probably do more harm then good.

When the A/C shut off. It would have a chimney effect. And let the first floor heat rise into those rooms. making them worst then before.

May also violate code.

Since in a fire. The fire would be able to travel though that wall chase from the first floor to those second floor rooms even with the doors closed.

To clarify, the stairwell grill would be at the level of the second floor, so the length between high and low grills would be about 8 feet (could be less). My comment was intended to imply that air flow out of that (stairwell) grill would flow to the downstairs grills (my guess).

Amp

[Brian GC]

To clarify, the stairwell grill would be at the level of the second floor, so the length between high and low grills would be about 8 feet (could be less). My comment was intended to imply that air flow out of that (stairwell) grill would flow to the downstairs grills (my guess).

Amp

Amp,
Are you trying to improve the performance of the AC, heater, or the fan in general?

Overcutting the bottom of the bdrm doors to 1” will give you about 30sq inches of return per room. Using a stud bay will give you 49sq in. of return area minus the loss of 8ft of travel plus the loss of two registers grills. The two methods may be equal.

It would boil down to whether you want the hot air on the ceiling or the cooler air on the floor to be removed from the rooms.

As for code violations, I believe that only applies to firewalls (garages).

And, the only air that would travel from upstairs to the downstairs returns would be the cooler air.

Brian

[udarrell]

Manual D says ,return location high or low has little effect on comfort,believe it or not.

Right Dash, however, Manual D assumes that the duct system will be done correctly according to their standards.

Where we have old gravity flow supply registers & very low airflow (No Throw) due to Evaporator being installed directly on top of an OIL furnace when it should be 6" above it, etc.

We end up with cold air dropping on the floor & recirculating back through the floor returns. Room-air stratification, & very Low heatload through cooling Coil. Then, where the SA/RA grilles are located does make some difference.

Of course, the initial mistakes should be corrected, but many don't have the money to get it done right. - Darrell

[ampulman]

Amp,
Are you trying to improve the performance of the AC, heater, or the fan in general?

Heating system is good overall; would benefit 2nd floor due to center hall (high) return and closed room doors. Ditto a/c, especially on low stage.


Overcutting the bottom of the bdrm doors to 1” will give you about 30sq inches of return per room. Using a stud bay will give you 49sq in. of return area minus the loss of 8ft of travel plus the loss of two registers grills. The two methods may be equal.

It would be very easy to cut 'pass-through' returns over each doorway. Would the 1" door cut lessen noise (voice) transmission as compared to the door cut? The door cut is a direct pathway (~1.5") for the sound to travel through vs. the distance between layers of sheetrock?




The high returns in each room would preferably benefit cooling

[quote]And, the only air that would travel from upstairs to the downstairs returns would be the cooler air.

I'm familiar with cold air spillage from the second floor. The proposed returns (in the stairwell) would be at the level of the 2nd floor. I would think the return air would be caught in the spillage.

Amp

[dash]

NOT !!!

Ouch! That's loud. Feel better now? lol!!!

[gena]

“Manual D says, return location high or low has little effect on comfort, believe it or not.”
Just curious: Is this part of the Manual D written on the toilet paper?