This wall vent blows hard, with cold current dumping atop the dining table.

Common dining room issues:

Register blowing a draft onto the table

Window area near the table gets too hot or cold, can feel it

Dining area is too cold, kitchen nearby too hot in summer






Ventners offer instant improvement.

Now air will be streaming at diners' feet - not upon their heads.

And the kitchen area will be better aerated.

And those glass doors and windows will get air, equilibrating their surface temperature.

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One could tear open this mid-century home, install linear slot diffusers in the narrow flat-roof ceiling for $20k+, scrub and arrange everything and call the magazines.

This is a rendering. It illustrates clear ventners, which look better in real life.
But not as slick as linear slot diffusers. 

In reality, we seldom stare up at registers. Hopefully people are looking at each other, likely their phones. And this solution costs under $70. 

Spend that money on a long vacation, and keep your vintage home authentic...