While you should have a filter on your air return vent to prevent too much dust or moisture from entering your air system and recirculating back to you, you should never actually cover a return air vent.
Make sure that the return vents are never blocked by furniture, area rugs, long drapes, large toys or other household items. Additionally, vacuum or dust the vent covers periodically to remove any collected debris. To promote good airflow you should also: Check the system's air filter monthly and replace it as needed.
Never cover return vents. Blocking these crucial airflow pathways forces your HVAC system to work harder, increases energy consumption, and can lead to premature system failure. Keep furniture and curtains at least 10 inches away from returns to ensure proper function.
Never cover a heat vent with a piece of furniture or fabric. Doing so weakens your home's heating system and is a fire hazard. Keep any electronics, perishable food, and books a few feet away from heat vents. Store flammable items on the opposite side of the room from heat vents.
What Can Happen if You Block HVAC Return Air Vents? Several things can happen if you block an HVAC vent. First, it can decrease the performance of your heating or cooling unit. This factor, in turn, could make it more difficult, or even impossible, to keep the air in your home at a comfortable temperature.
Can mice come through vents? Mice are small and flexible enough to get into many tight spaces, including air ducts. The Centers for Disease Control (CDC) warns that mice can squeeze through a hole as small as a nickel and that rats can get through a hole as small as a half-dollar.
While plastic may work for low-traffic, low-heat areas, metal vent covers offer better durability, safety, and health advantages, making them a superior option for most homes.
The biggest fire risks in the home
According to the U.S. Fire Administration (USFA) and the National Fire Protection Association (NFPA), around 2,900 home clothes dryer fires are reported each year in the United States. These fires cause an estimated five deaths, 100 injuries, and over $35 million in property damage annually.
While you should have a filter on your air return vent to prevent too much dust or moisture from entering your air system and recirculating back to you, you should never actually cover a return air vent. Keep furniture and even curtains at least 10” away from the vent opening in order to allow for proper air flow.
HVAC Return Air Requirements: Codes and Best Practices
Square Footage Guidelines: A typical rule of thumb is one return vent for every 600 to 900 square feet of living space. Larger areas, such as homes over 2,000 square feet, generally need multiple return vents.
If you've changed filters, cleared vents, and still notice:
Closing house air vents in unused rooms may damage your HVAC system, leading to costly repairs. Your heating or cooling system produces the same amount of air regardless of how many closed vents you have. Avoid closing AC vents completely to keep air moving and avoid potentially higher energy bills.
You can place furniture around vents if there's 6-12 inches of space for airflow. The more space you leave, the more effectively your system will operate.
Instead, they pull air back into the HVAC system, which is why they're often overlooked. Over time, blocked return vents restrict airflow and disrupt system balance. When this happens, you'll often notice doors slamming shut, whistling sounds, or rooms that feel stuffy or have weak airflow.
Whilst they can start naturally, see Information note - Wildfire, it is estimated that 90% of all wildfires across the globe are caused by humans. About 30% of those are started as a deliberate act of arson, whilst 70% are started accidentally or as a direct result of human carelessness.
Cooking. Unattended cooking is listed as the number one cause of residential fires. Here are a few proven tips to help reduce the risk of starting a fire while cooking: Never leave your stove unattended when cooking.
Vents that are not properly sealed or have loose covers can be an easy access route for mice. Once inside, they can move through your home using the vent system. They are attracted to warm spaces, and vents often provide just that. It's crucial to be aware of this possible access point and take action to secure it.
You might create mold and mildew.
You most likely thought covering your air vents would certainly save you energy, but it does the opposite. Considering that this could damage your cooling and heating system, fractures and other damage could allow air to leave your air ducts and cost you much more in energy bills.
Despite its name, duct tape is not meant for air ducts.
Natural Smells the Amish Use to Repel Mice
Traditional methods often include using natural deterrents like peppermint, pine, or other strong plant-based smells. Whether it's growing plants near entry points or using oils indoors, these scents can interfere with how mice navigate and make the space less appealing.
You might think that spotting one mouse means you only have one mouse. This rarely happens. Mice live in family groups and reproduce quickly. If you see one mouse during the day, it usually means the hidden population has grown large enough that they're competing for food and space.
Mice are unlikely to climb on you when you sleep unless they are already in the bedroom. The best way to keep them out is by not giving them a reason to stay.