I am putting in new gas forced hotair furnace and ductwork. House is one story and on a concrete slab so duct work must go in attic. The installer suggests putting the supply registers in the center of each room with 360 degree air diffusers on all registers. And central cold air return in the center of the house ceiling. The house is quite small at 900 SF.
I don't agree with that placement of the supply registers and thing they should be placed nearer the outside walls with a 180 degree diffuser and the central cold air return at the bottom of inside wall.
Which way would end up being the more efficient way>
Thanks

I agree with your idea. Supplies should be located near ouside wall over windows and outside doors, just as they would be if they were in the floor. And return/s on inside wall/s near the floor. You will be fine with either the 360 or 180 diffusers.

Thank you for the reply.
When I questioned the installer about not putting them near the outside walls he used phrases like "you won't know the difference","thats the way I have always done it" and a couple more meaningless phrases that raised a red flag to me.
Now I will try to find some sort of formula/directions on how much distance from the outside wall with what style diffuser so the heated air can flow down the wall without creating a draft
Thanks again for the reply