Issues Caused By Closed Air Vents

closed air vents

A common HVAC myth is that closing air vents in unused rooms will save you money and energy. Did you know the opposite is true? The are many issues caused by keeping air vents closed even in unused rooms. It is important to remember that your HVAC units and ductwork are designed to work together and can be disrupted if air vents are closed. Closing vents causes your HVAC system to work harder and can lead to HVAC damage and cost you money in the long run. Below we discuss issues caused by closed air vents.

Lost Efficiency

Your HVAC system will not account for closed air vents in your home. Your system is sized to perfectly condition your home and will always produce the same amount of heated or cooled air until it reaches the set temperature on the thermostat. Closed registers will build pressure in the system and make your HVAC system work harder to distribute the air. This causes a decrease in efficiency and compromises the blower. If you have a PSC blower,a closed vent will cause the blower to slow down and the system will take longer to reach your desired temperature. On the other hand, an ECM blower can adjust its speed under different conditions. An ECM motor can overcome the extra pressure caused by a closed air vent, but it will lead to higher energy costs and potential damage to components. When your system is working harder to reach your desired temperature you are not going to save money. You will pay more, cause early damage leading you to HVAC replacement much sooner than you expected.  

Early System Damage

Closing off too many air vents in your home will restrict airflow. Restricted airflow causes many issues on its own and can lead to coils freezing and damage to the compressor.  If the compressor is damaged, you will need to repair it or replace it before your system is able to operate properly and efficiently. Furthermore, reduced airflow can also cause the heat exchanged in a furnace to overheat and possibly crack.  It is possible, that your HVAC system may completely breakdown due to the damage even on a day you need it the most leaving you to have to repair or replace it.

Inconsistent Comfort

Closing air vents disrupts airflow and temperatures throughout the entire HVAC system. Supply air is controlled by internal dampers to maintain consistent temperatures throughout your home regardless of room location. When a vent is closed, rooms closest to the blower may receive too much air, while rooms that are located farther away may not receive enough.

Pressure Imbalance

Return registers always remain open, but when you close supply vents it causes a pressure imbalance in the system. This means the return system continuously draws air out of a room even when there is no supply air entering the room. This leads to depressurizing of a room or even a part of the house. A depressurized room will still draw unfiltered air through any small cracks or gaps. This air can lead to room temperature imbalance and can lead to poor indoor air quality.

Duct Leaks

Not only can closed air vents lead to damage of your AC and furnace it can also cause ductwork to leak or burst. It is estimated that the average home will lose about 20 to 30 percent of airflow through small leaks or poor connections in the duct system. Closed registers can cause the pressure to build and turn small duct leaks into bigger issues. Cooled or heated air then ends up where you do not need it either outside or in attics or crawlspaces. Keep air vents open to enjoy your heating and cooling system properly and efficiently.

Mold Growth

Closed air vents can lead to condensation occurring in other rooms where the air coming out is too cold compared to the room’s temperature. The condensation can then result in mildew and or mold growth which you will likely be able to smell before you see it. By keeping air vents open you can help prevent moisture buildup and mold spores from circulating throughout your home.

Increased Carbon Monoxide Risk

Closed air vents make it much easier for the heat exchanger in your furnace to crack, which can release carbon monoxide into your home. Carbon monoxide is a gas that is tasteless, colorless, undetectable to humans and can lead to death. Keep your air vents open and install a carbon monoxide detector in your home.

Other Ways To Save Money

It is not guaranteed that closing vents will lead to permanent damage to your system, but it does cause your system to work harder and inefficiently.However, the more air vents are closed and the longer they remain closed the more likely it is that you will experience issues with your HVAC system. You may end up paying more and decrease your system’s lifespan while putting your health and safety at risk. Instead of closing air vents, to reduce energy costs year-round try the following:

·        Schedule regular professional maintenance for both AC and furnace

·        Use a programmable thermostat

·        Use blinds, shades or reflective window coverings

·        Have your ducts inspected

·        Use a ceiling fan

·        Consider upgrading to a new more energy-efficient unit

Contact LA Construction Heating and Air

If you are experiencing any issues due to closed vents, contact us at 818-341-3406 or online. Our professional trained HVAC service technicians will address the issue,diagnose, and repair your system.

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