We are adding new heat supply runs to our basement ceiling. We have had 3 HVAC contractors look at it and all 3 want to use 5" round air diffusers instead of the normal metal square registers. Here is an example.
We do not have a/c and are only supplying heat. They want to place these within a foot or so of the exterior wall by the window.
None of the contractors gave a good reason as to why to use these instead of square registers. They just state that's what we use now and it doesn't really matter. My understanding is they are great for A/C but cant find any info on heating.
Question: I would like to know if we should use these round diffusers to provide heat in a basement, will the heat just sit up in the ceiling?
If we use these, how far from a window should they be installed to be efficient.
We are putting cold air returns near the floor. Also I am up in Canada so have to deal with cold winters.
Thanks for the help