Should I block air vents in winter?

Author: Filomena Toy  |  Last update: Thursday, December 4, 2025

Closing HVAC circulation to certain rooms may result in issues with your ducts. It creates a less efficient heating and cooling system and can be dangerous. Ultimately, closing vents in your home isn't a good strategy for saving on energy costs.

Is it good to close vents in unused rooms in winter?

It is typically best to always leave your air vents open, even in unoccupied rooms. It may sound counter-intuitive, but leaving vents open will use less energy, extend the life of your HVAC unit and save you more money in the long run.

Which vents should be closed in winter?

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.

Should house vents be closed in winter?

If you must close your vents during winter I highly encourage you to do it only when the temperature drops below 32⁰. Otherwise, keep them open when the temperature is consistently above freezing to avoid moisture-related problems. Learn more about Sedona Waterproofing Solutions.

Is it okay to block up an air vent?

No, it won't damage the system. But closing vents, closing doors, blocking return air vents will cause high and low air pressure zones within the house.

Misconception: Should I Close Crawl Space Vents in Winter and Open in Summer

What happens if you block your air return vent?

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.

Does closing doors to unused rooms save energy?

But does closing doors save energy? Surprisingly, the answer to that question is no. Sealing off unused rooms may seem like a smart way to save energy on cooling your home. On the contrary, it can affect your home's air pressure, creating drafts that can cause expensive and potentially dangerous conditions.

Can I cover air vents in winter?

While blocking air bricks may seem like a good way to keep the cold out, it can cause more harm than good. Covering these vital vents stops fresh air from flowing into your home. This lack of airflow leads to damp and moisture buildup. Damp conditions are perfect for wood rot and mould growth.

Is it better to keep air vents open or closed?

The short answer is no; closing your vents does not save energy. When you close vents in unused rooms, your central air conditioning and heating system will push the excess air to other places in your home and build pressure within your ducts.

Should I turn off ventilation in winter?

Ventilating is important all year round. During the winter months, you should open your house at least once a day, no matter how bitterly cold it is outside. It doesn't have to be for long, opening a window or door for even just a few minutes will create a cross-draught.

Is it okay to cover air vents?

A blocked air vent can permit mold or mildew to develop in and around your vents and ductwork if you reside in a humid location. You can be wasting money on utility costs. You most likely thought covering your air vents would certainly save you energy, but it does the opposite.

How to block air vent in bedroom?

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.

Do vents make rooms cold?

In conclusion, Positive Input Ventilation (PIV) systems do not make your house cold. They are designed to maintain a healthy indoor environment by controlling humidity and preventing issues like condensation and dampness.

Which vents should be open in winter?

Here's what to do:
  • In colder months, close supply vents in higher locations, like up by ceilings, while opening lower ones on floors or close to baseboards. ...
  • In warmer months, do the opposite — open the supply vents in higher locations and close the ones placed lower.

Is it better to keep rooms open or closed in winter?

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.

Why is my second floor so hot in the winter?

First, heat rises, so it's normal for the second floor of a home to get hotter than the main floor.

What happens if you block an air vent?

Blocked vents increase air pressure in your ductwork, which can create cracks and leaks. Clear vents ensure every room in your home gets good circulation so your system can work as designed. Have a piece of furniture sitting over a vent? Try using an inexpensive vent extender to direct air out into the room.

Does shutting vents in unused rooms help?

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.

Should house vents be open or closed in winter?

Leaving crawl space vents open in the winter allows cold air to enter, making your heating system work overtime to maintain warm indoor temperatures. Sealing crawl space vents enhances energy efficiency and may reduce energy bills, saving money and reducing strain on your HVAC system.

How do I stop cold air coming through my vents?

Ensure that all the ductwork connections are sealed properly on the interior and exterior points of the ductwork. You can seal gaps using metal tape, foaming insulation spray, or mastic sealant. You do not need to remove any existing sealant and may build up the sealant over top of any current filler.

What happens if you block up an air brick?

If the air bricks are blocked or closed this will reduce the ventilation and the risk of serious rot and damp will be increased. Air bricks should never be blocked or closed and it is recommended that all air bricks are inspected and cleaned on an annual basis.

How to cover vents for winter?

In my house, the vents are 13 inches by 13 inches, and 9 inches by 9 inches. Cut two corrugated plastic squares for each vent. Use a craft knife, tin snips, shears, or even scissors. If your vents are rectangular, be sure that one piece of corroplast has its ridges running at right angles to the first.

Why you should always close your bedroom door?

Creating a Safe Refuge

A closed door can create a temporary safe space that keeps the intense heat and toxic smoke outside. With the door closed, the air inside the room stays cooler and cleaner. This “safe zone” can be the difference between life and death as it gives firefighters additional time to rescue you.

Is it cooler to sleep with bedroom door open or closed?

Sleeping with your bedroom door closed can help maintain your desired temperature, which is crucial for a restful night's sleep. In the summer, sleeping with your bedroom door closed can help keep the air conditioning in, while in the winter, it can help keep your bedroom warm and toasty.

Does closing off rooms save heat in winter?

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.

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