Closing HVAC 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.
The Impact of a Blocked Air Vent on Your HVAC System
Even one blocked vent in the home can cause an inefficiency in air flow, which means your HVAC system will likely have to work harder to achieve the desired temperature. The result may be a home that is riddled with uneven temperatures from room to room.
Closing one or more vents can disrupt the airflow and temperature balance of the whole system. This can cause issues such as insufficient airflow in rooms far away from the blower or excessive airflow in rooms closest to the blower.
It's true that turning off radiators in unused rooms will likely save energy. However, it may not reduce your heating bills and might actually increase them! Why? Because your energy consumption and heating bills don't always match up as you'd expect.
When air can not move effectively, a pressure buildup can get created inside your air ducts and also your HVAC device. This will inevitably produce less airflow as well as cause your heat exchanger to split which will certainly enable carbon monoxide gas to leak into your residence. You might create mold and mildew.
Lost Efficiency
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.
We've seen how it can create safety hazards, mess with your home's heating and cooling, and even damage your bed. Blocked vents can cause fire risks, poor air quality, uneven temperatures, and moisture buildup. Instead of covering vents, try rearranging your furniture or using vent deflectors to direct airflow.
Contrary to popular belief, closing your bedroom doors does not improve the efficiency of your HVAC system and may actually increase your utility bills. When you close a bedroom door, you effectively block the air's pathway, and that blockage can lead to issues with airflow.
The NHS recommends the ideal room temperature should be between 18-21°.
To utilize your supply vents strategically, we suggest: Closing supply vents in higher locations by your ceilings while opening lower ones on floors or close to baseboards. Doing this will direct more warm air to the floor, where it will rise to heat the whole space.
In winter, particularly in cold climates, closing crawl-space vents can help prevent cold air from entering the space and potentially freezing pipes. The simplest way to close foundation vents for the winter is to plug them from the outside with foam blocks made specifically for this purpose.
AC Vent Open or Closed: What Experts Recommend
Balanced Air Pressure: Keeping vents open maintains balanced air pressure in your ductwork, allowing your HVAC system to run more efficiently. Consistent Temperature: Open vents help achieve a uniform temperature throughout your home, enhancing comfort in every room.
There Are Dangerous Long-Term Effects On Your System
The pressure built up within your system due to closed vents can also result in long-term damage to your system. Leaks can be caused or made worse inside your HVAC system ducts, which can greatly impact the efficiency of your system.
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.
Avoid blocking air vents with pillows, furniture, plants, or pictures. When the air vents are blocked it means that heated or cooled air needs to squeeze by what is blocking it to reach the rest of the room.
Closing vents in individual rooms will not help your energy cost, but actually hurt your system. “Closing vents puts a strain on the system, which in turn causes the system to work harder,” Martin says.
There may be drafts and pockets of colder air near the floor; The walls are colder and don't emit the usual amount of infrared radiation, so you lose heat due to your body emitting more IR than it receives; You may spend more time indoors and hence have less physical activity, so your body generates less heat.
If you have rooms in the house which you rarely use, it makes sense to turn the radiators off and close the doors when you don't need the room. There's probably only one disadvantage in doing so, which is the damp problem.
Contrary to what most people think, closing the vents in a room doesn't divert that air to other rooms. What's actually happening is that air will leak from the ductwork, sending cool air into areas such as interior walls and attic spaces.
Block Off the Vent: You can block the vent by placing a piece of furniture at the opening or purchasing a magnetic damper that's strong enough to stick to the steel on the wall or ceiling. Plastic sheeting can be placed over the opening as well. You can also install a vent grille filter.
Yes, open doors are generally better in winter to maintain a consistent temperature. They allow your heating system to distribute warm air evenly across rooms, improving comfort and efficiency while preventing energy waste.
You run the risk of causing damage to the heat exchanger
A buildup of pressure from air being pushed to covered vents can cause difficulties with your heat exchanger, causing it to shatter and release carbon monoxide into the atmosphere.
Not only does it force your HVAC system to work harder—shortening its lifespan—but it also results in frozen air conditioning coils, overheated furnaces, cracked heat exchangers, and leaks in duct systems. Those issues come with both danger to your home AND big price tags for repairs.
Without proper ventilation, carbon monoxide can build up inside the house, which is incredibly dangerous as it can cause illness and potentially be fatal. As a result, many furnace manufacturers design their units so that they shut off automatically when the vent becomes blocked.