If you have vaulted ceiling then you will need to install some registers near the ceiling on one of the walls.
Difference in attic or crawl space.
It s easy to see your point about eliminating ductwork from the attic.
Installation whether using a concrete slab 1 or a crawl space only a professional should prep the site and install the foundation.
The cellar and the attic.
The attic would be fine if the equipment and duct work were installed in conditioned space.
To get the target r value from the product you chose use the number of bags your calculations showed that you needed to insulate your attic never fewer.
A two room addition on the 1st floor has limited attic space and a 4 crawl space.
A person who has turned his attic into an office or a guest room for example might still have a crawl space if one section of the attic was too low to be used for living purposes.
Seal supply boxes with mastic.
Strap ducts out of insulation with 3 ductstraps per specifications.
If it applies to energy auditors and raters too that could really be difficult because many times they go into a house on their own.
Insulate and air seal the floor with open cell foam put ductwork and mechanicals in the attic install a radiant barrier and mastic seal the ducts.
Knowing the disadvantages of attic install and the crawl space install.
I vote for the attic.
With new construction i would look for a way to have them in conditioned space.
Learn the 7 biggest differences between two popular foundation types slab vs.
Since a crawl space can be anywhere from 16 inches to four feet high a crawl space built home needs to have entrance ramps to provide the same ease of mobility.
To make it easy to eyeball how level the material is as you blow it in screw depth guides to joists throughout the space.
In the attic you have worry about heat gain and duct losses.
My vote would be the crawl space if there is sufficient room and easy access for service.
In some rare cases the term attic crawl space refers to a section of an enclosed section of an attic with a low ceiling that is situated within a larger more habitable attic space.
If there were a way to eliminate the possibility of critters i would prefer the cooler location for ducts.
However i have two questions if i want to centrally air condition my entire house.
Crawlspace definition in a building an area accessible by crawling having a clearance less than human height for access to plumbing or wiring storage etc.
Crawl space so you can make the best decision when you have a new home built.
This is a big deal and has the potential to add significant cost to air sealing insulating crawl space encapsulation and all those things we do in confined spaces.