fan-of-fans
Well-known member
Not sure if I've posted on this before, but I've always liked the round ceiling air diffusers that older homes had. I've seen them in many older homes built during the late 1950s and early 70s. I don't think I've seen them in any house built after about 1972. Although I did see them in one house built in the 1990s, but that's the only one.
I always wondered why these earlier systems used the round diffuser in the middle of each room, whereas after that up through now most houses tend to run the main duct down the middle of the house and have rectangular diffusers along the walls.
My guess is it was cost cutting, as doing that allowed less duct to be used than running a separate branch to the middle of each room. I guess it could also be more efficient as it allowed less temperature change before the air reached the diffusers.
I think the diffusers on these were typically about 10" or 8", some had pull chains to shut off the air flow, whereas others had a plastic knob that was turned.
I have seen replacement diffusers and dampers for sale in 10" and 8" at Lowes and Home Depot, but I haven't seen them used in new construction other than commercial buildings, where they are much larger. I'd guess the commercial ones are about 3-6 feet in diameter.
Online I've seen you can order the residential ones in sizes of up to 14".
Just wondering if anyone else liked these.
I always wondered why these earlier systems used the round diffuser in the middle of each room, whereas after that up through now most houses tend to run the main duct down the middle of the house and have rectangular diffusers along the walls.
My guess is it was cost cutting, as doing that allowed less duct to be used than running a separate branch to the middle of each room. I guess it could also be more efficient as it allowed less temperature change before the air reached the diffusers.
I think the diffusers on these were typically about 10" or 8", some had pull chains to shut off the air flow, whereas others had a plastic knob that was turned.
I have seen replacement diffusers and dampers for sale in 10" and 8" at Lowes and Home Depot, but I haven't seen them used in new construction other than commercial buildings, where they are much larger. I'd guess the commercial ones are about 3-6 feet in diameter.
Online I've seen you can order the residential ones in sizes of up to 14".
Just wondering if anyone else liked these.