HVAC floor vents are found in homes that have a furnace in the basement or ducts that travel from the furnace through crawlspaces beneath the floor. Because heat rises, warm air can enter a room more quickly through HVAC floor vents. Homes with multiple stories will typically use floor vents for heating and ceiling vents for cooling.
We have a diverse catalog of HVAC floor vents and grilles, which you can browse here.