Round ceiling diffusers

[fan-of-fans]

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.

https://www.supplyhouse.com/Hart-Co...AQJ268I1aiUhL2xgKBhT2X2Fvwv8lk2BoCsR4QAvD_BwE

 

[mattl]

The placement of heating and cooling runs are generally placed where the temperature difference is the greatest, usually bu windows and out side walls. This is done to counteract the loss.  Central locations are poor at doing this.

 

[nanook]

I can't say I'm a particularly big fan of round diffusers used in residential homes; although in commercial applications they strike me as just fine. (Go figure). I would say round registers tend to 'make a statement', whereas rectangular units tend to sit flush to the ceiling - or close to it.

Obviously, the airflow from round registers is fairly uniform, so placing a single register in the middle of a room would be "most efficient". Rectangular registers [generally] have more options for directional control. There are numerous reasons for placing registers along the perimeter of rooms - such as, if the cold air near the window is heated, the whole room stays comfortable with less energy. There's no need to heat the warm air, just the cold air, etc.

 

[circlew]

I think the round ones look good in a modern, industrial style house, especially if the ductwork is exposed. I was in a model home of that type a few years ago; lots of concrete, steel, and glass, and exposed round ducts with round diffusers.

 

[arbilab]

Our 1953 'ranch' had round ones but the 57 were flat/rectang.

 

[gredmondson]

The house my folks built in 1959 had round diffusers. In the center there was a handle that regulated the airflow and by the time I was 14, I was tall enough to reach it. I thought they were cool at the time. But, what I really liked about that house was the central forced air and refrigeration in Bakersfield, California. The HVAC man said to set the thermostat to 72 F. It stayed there for decades.

 

[searsbest]

Round diffusers

Our summer home in Maine was built in 1950, some of the ductwork is still wrapped with Sears Homart insulation. Which really makes me wonder how much more of the house had Sears building products in it. There have been some updates, a new furnace in 1983 ( still running strong) bath, and kitchen have been updated twice (second time due to a water issue). The house still has its original diffusers, all painted their original colors. The house has textured plaster walls and ceilings, all painted in matching pastels. The front porch was enclosed in what I could guess was the 1970s and it has a square diffuser. I really love them all and think they really add to the appeal of the house. My camera didn't pick up the color in the ceilings as it should have, the paint matches the diffusers almost perfectly.



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[DADoES]

 
Family house built in 1964 had round registers, as does the next/current one (built in 1972, we moved there in 1980).  Both my houses (1983 and 2004) have rectangular.  I don't have a preference.

 

[sudsmaster]

I had a rental house in Berkeley in the 80's that had a round ceiling diffuser in the living room. The place had forced air central heating. The other rooms had rectangular air outlets. It all seemed to work OK. I think the house was built in the late 30's.