Most new installations of grilles and diffusers involve a suspended ceiling grid, but some installations require surface mounting. Square ceiling diffusers and filter grilles can present the biggest ...

In conclusion, to minimize smudging around ceiling diffusers, install and service filters for all primary air sources. Periodically clean supply air ducts as required.

QWe have seven-inch round ducts in the ceiling of our house, for heating and air conditioning. In a little-used room, we’ve never bothered to find ceiling diffusers for them. Now that we’d ...