The typical practice of improvising an Air Distribution System at the time of installation leads to compromises in aesthetics and performance, and in this case, it would have led to disaster!
The end of one wing was a Family room, 26 feet by 26 feet slab on grade, and 24 feet tall to a contact ceiling. A balcony supported by a steel beam looked out over the room toward a solid wall of glass--26x24 feet, facing west.
The architect designed a permanent shade structure, but there was still no place for supply grilles but through the steel beam: 1,280 cfm, throwing 16 feet.
And cool looking! I had them cut into the beam during fabrication.
Designing an Air Distribution System before construction begins gives the architect and I the opportunity to locate and design return and supply grilles where they are aesthetically pleasing while functioning to their highest level—mixing air into rooms effectively, quietly, unnoticeably, protecting indoor air quality and creating an exceptional level of comfort.
All of the return grilles were sized for very low face velocity and custom built to be installed flush with the sheetrock and maintain the clean trim-less look.
You can get flush wood supply grilles from your “flooring guy,” but I have never seen any constructed to provide the throw and spread necessary for proper diffusion. Some of these are designed to throw in only one direction.
The rest of the Air Distribution System consists of “twinned” air handlers which distribute the full airflow required for proper mixing, while staged geothermal heat pumps provide only the minimum heating/cooling ambient conditions require. (This is not at all the same as a “two stage variable speed” system!)
The approach to the home is from a slight elevation and the architect didn’t want to see penetrations from 6 bathrooms, so we tied all but one into a single exhaust system with motion sensors and timers..
These, along with a commercial kitchen range and a wood burning fireplace, led me to design an automated but also owner-controlled make-up air system, in addition to the fresh air ventilation brought in through dehumidifiers, all integrated into the primary HVAC systems.
Comfort though, actually begins, not with the air conditioning system, but with the insulated enclosure. This home has an R57 roof—R42 Dense Pack Cellulose (DPC) within the framing and another R15 rigid PIC on top.
As with many Modernist designs, there are no roof overhangs, so the walls are designed for maximum drying with R21 DPC, plywood sheathing, a fluid applied WRB and ¾ inch rain screen.