If you are going to close vents in unused rooms, then you should reduce the amount of airflow your HVAC system is producing. This is because closing an air vent only redirects the excess airflow to other areas of your home, which can cause leakage and energy wastage, and contribute to long-term damage. However, you should never close more than 25% of your vents as the system won't have enough outlets to push the air out of, which could lead to burn out.
Seeking high quality vents? View our large selection here.