Protect Airflow and Decorate Your Vents
Whatever route you choose to decorate your HVAC system some precautions should still be taken to ensure it’s working as it should. Covered air vents would not allow air to flow properly and would damage the unit. Restricted air ducts can also put a strain on the airflow, leaving you and your family uncomfortable in the winter.
However, you can still hide those vents with some tinsel or snowflake decorations. As long as you’re not changing the flow of air or cover the vents in their entirety, you can still add all the festive flair you want. If you have vents on your baseboards, it might be a bit tougher to decorate, but at the very least, you can place some cinnamon bunches near them to improve the smell of your air.