Should I Block Cold Air Return Vents In The Summer? You should never block your air return vents.
Dangers of Blocked Cold Air Registers
If your HVAC system is designed this way, blocking off a single return vent can wreak havoc on the system and lead to: Pressure imbalances that let allergens and pollutants get pulled into your air supply from unconditioned areas.
So how much space does an air return vent need to work properly? Home Inspection Insider explains that an air return vent needs 6-12 inches of space in front of it, and recommends that you do not put large, bulky furniture like couches and bookshelves in front of an air return vent.
Unlike fully closing the vents, partially closing them still allows for proper airflow through the HVAC system. This prevents overheating and reduces pressure inside the ductwork. Because heat rises, homeowners can consider partially closing upstairs vents and fully opening those downstairs.
On the heating side, if you block off the return, the exchanger can overheat. “In extreme examples, it can crack and fail,” Smith says. “They're all designed to have that proper airflow and bad things can happen when that's thrown out of whack.”
Closing supply vents throws your heating and cooling system off balance, creates airflow problems, and makes the system work harder. That's why it's better to keep all the vents open for optimized airflow and energy efficiency.
If comfort is an issue, try closing certain vents partially. Closing vents no more than 75% of the way can ensure that air keeps circulating throughout your home so the pressure is even and your energy bills stay as low as possible.
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.
Closing the vents doesn't do it any favors. In fact, instead of helping the air conditioner cool less, closed registers force the same amount of air through other ducts. This builds pressure in the system and makes your HVAC system work harder to distribute the air where you need it.
The repercussions of a blocked air vent can extend beyond just the unit's inefficiency, actually causing it to break down over time. The furnace's heat exchanger and the air conditioner's cooling coils rely on air to regulate their temperatures. If this air level is reduced, the heat exchanger can overheat.
Return air ducts must be sealed and unobstructed — Sealing return air ducts is just as important as sealing supply ducts. Sealing all duct section connections with mastic, a specialized rubbery sealant, or with metal tape prevents air leaks.
Return vents are usually larger than supply vents and are in large rooms in the home. The return vents in your home help equalize the pressure that changes as your HVAC system heats or cools your home. These vents should never be fully closed because closing them off restricts airflow and strains the system.
If you prioritize heating, put the HVAC and vents in (or below) the floor. This principle works for return heating vents as well. Place returns for cooling in the ceiling where the warm air congregates and heating returns in or near the floor where the cold air congregates.
Hot air rises and cool air sinks. Therefore, opening the right return vents in the summer and winter significantly improves the distribution of air by your forced-air system. You'll also enjoy more even heating and cooling throughout your home. In the summer, open your high returns and close the low ones.
Dropping a mattress directly onto a floor vent will completely restrict the airflow and prevent the HVAC system from heating or cooling the space. This, in turn, can cause the HVAC system to work overtime, leading to premature wear and tear.
The filter belongs on the return side of your HVAC's furnace and AC system. It's a “must” to have one there. And if you have a return air filter of the right size that is properly installed, then there is no need for a supply vent filter.
While having a return vent in every room is unnecessary, it's becoming more common in modern homes. You should ensure a balanced distribution of these vents throughout your home. This ensures that air circulates effectively, preventing hot or cold spots.
A standard but incorrect solution is closing vents. People think that if they close vents on the main floor, the system will push more cool air to the upper floor. This strategy often results in reduced cooling performance. If you have a minimal number of vents you should not close any.
One common strategy is closing air vents in unused rooms or little-occupied areas to redirect heat and increase efficiency. While this might seem like a smart, cost-effective solution, it can actually increase energy consumption, strain your HVAC system, and lead to costly repairs.
Reduced efficiency: Your HVAC system will work less efficiently if you block a return air vent. This will make the units use more energy and will raise your utility costs.
Down Low: if you have your air return lower on your wall it will function better as a cold air return. This will allow your air return to draw in cold air as it sinks to the bottom of the room. Making it more efficient at recirculating this cold air through your furnace to repeat the heating cycle.
Cold air returns should be strategically placed throughout your home. You'll typically find vents or grills in every room or at least in every area served by your heating and cooling system. They are often located on lower walls or in the floor and are usually larger than supply vents.
If these air return systems are obstructed, not only will you block the proper airflow and create stuffiness in the rooms of your house, but you will have uneven cooling or heating, lack of proper filtration, and potentially higher energy bills.
EXPERT RECOMMENDATION: If you want to try to balance the airflow throughout your home, you should not close vents completely; HOWEVER, you can close them slightly (not more than 75% closed) to help distribute air better to the areas that need it most.
Symptoms include weak airflow and uneven cooling or heating throughout your home, with some rooms feeling much cooler or warmer than others. Homeowners should regularly check vents for consistent airflow. If you notice a significant drop in air pressure or uneven temperatures, it could indicate return air issues.