Old box style register boots

[skunkiechris]

I have a very old house, with large (12 x 8 or 10) floor registers. These registers have large square box shaped boots, with the ducts running into one side of them. I assume these are left from the days of gravity furnaces.

The air basically comes in and is pointed straight at the opposite side of the boot, with the grill above. The air obviously does come out at the floor...but what I'm wondering is this: Would it be at all beneficial for efficiency or reducing pressure to add a diagonal piece of sheet metal like a rampt to "direct" the airflow upward. Or would it really not make any difference?

Thanks for any feedback!

[Steve Wiggins]

I would get an asbestos report before you go any further.

[skunkiechris]

Asbestos has all been abated. Ducts were removed and replaced, but the boots did not have any asbestos on them -- just bare metal.

[billygoat22]

You could put the metal in there upright to half the size of register. By narrowing from 12 x 8 to 12x 6 or 4, the air will be pushed up higher into the room and circulate air better.

[skunkiechris]

Thanks for the response! The incoming duct is actually on the narrow dimension on the box, so if I were to cut it in half it would be on the 12" dimension. Is there an advantage to putting the metal in straight upgright, vs "ramping" it as I initially mentioned? I (obviously) don't know much about this stuff, it just seems like the "ramp" would shoot the air up better...

Thanks!

[jacob perkins]

I liked your idea of turning vanes...do it and see what happens.

make an "airflow meter" out of light weight ribbons or something. see if the turning vanes push the ribbon further