Investor · Chicago, IL · Member since 2014 · 169 posts · 29 votes
Greetings all,
I live in the basement unit of my building which shares the same HVAC unit as the first floor. It is completely controlled by the first floor tenants but has six vents that are directed to the basement unit. I am going to move out soon and want to close those vents off completely so only the first floor receives the heat/air. There are baseboards in the basement unit as well which provide ample heat.
I've read before that closing vents in a room that doesn't get used actually isn't good for the system and was wondering if closing off the vents entirely will actually negatively affect my HVAC system or if this can be done.
Realtor · WV · Member since 2018 · 454 posts · 310 votes
7y
Typically when you close off vents permanently you would want to do it at the trunk line. If you want to do it temporarily and without opening up the trunk line, then close the vents and tape cardboard on the inside of the vents. This shouldn't hurt your unit but could make it run more inefficiently.
Investor · Chicago, IL · Member since 2014 · 169 posts · 29 votes
7y
Thanks Walter. I am looking to permanently close these. There are no returns in the basement, just the supplies so I don't think I can just close it at the trunk because the ducts share vents for both floors. If I did that would't I be stopping airflow to the entire duct, including the first floor?
I've found these rubber covers which would block the air from going into the basement but I'm not sure that would be good for the furnace in the long run. Ideally I'd like to have no registers in the basement ceiling so I don't really want to have to use these though.
Rental Property Investor · Rochester MN · Member since 2018 · 64 posts · 106 votes
7y
I have done this many times and use a thin magnet and just lay it over the face of the metal vent. I used an old magnet from a sign that you would put on a vehicle. I have seen that type at hardware stores, you can cut with a scissors to fit. The furnace should be fine, however make sure the airflow is not restricted upstairs by dust/dirt. Also, think about what percentage of the total vents you are covering. If the air temp blowing out of the remaining vents becomes "much hotter" that may be a sign that you are not getting enough airflow. You could test air temp before and after the blockage and then decide. Just my thoughts