Window Air Conditioning Vents Open Or Closed In Summer?

Summer is almost here. So, every homeowner is scamping to get the HVAC system ready, which is exactly how it should be given the dangers of prolonged exposure to hot musty indoor air.

However, getting your conditioned air in perfect condition in anticipation of the cooling season is just the first step to keeping you and your loved ones comfortable for the three to four summer months. You must also know how to use the AC properly.

Otherwise, you’re looking at compromised comfort, unnecessarily high utility bills, and accelerated appliance wear. Poor use may even lead to otherwise preventable damages, leading to costly repairs.

If you wish to maintain a comfortable house, you need to use zone temperature control. When you install a ductless heating and cooling system, you will have zoned temperature control in different rooms in both downstairs and upstairs rooms. This enables you to adjust the thermostat settings of your central HVAC system to work less.

So, today we want to discuss proper AC vent setup. Specifically, should your aircon vents be open or closed? So, let’s jump right in.

Should AC Air Vents be Open or Closed?

There is a popular and pervasive myth that you can save money on heating and cooling by closing off certain air vents in your home. The theory is that if you have an enclosed room in your house, closing vents to that room will save you money. Your supply vents should be open throughout the summer when the home HVAC system is in use.

When the supply vents are shut, the heated or cooled air will be redirected, making you less comfortable. It may increase static pressure in the ductwork supply, damaging the HVAC system and often leading to high energy costs. Speak with an HVAC contractor to learn ways in which you can reduce costs.

What are Air Conditioner Vents?

Aircon vents are air inlet openings found in some HVAC systems that let fresh conditioned air enter the AC to refresh the stale air inside your home.

The feature is most common in window ac systems and is identifiable as a louver system on the front of the AC that toggles open or closed via a manual lever. Interestingly, the air inlet pipe is located at the back of the HVAC system. Therefore, only the controls are found at the front of the AC for easy handling.

Note that most new HVAC system models don’t have the front lever. Instead, you’re likely to find an “Exhaust” setting, which performs the same function. However, others don’t have the vents altogether.

What Do Aircon Vents Do?

AC pushes out the cool, conditioned air through your ductwork as well as right into your home. Aircon vents are critical in achieving cool, clean, and healthy indoor air during the summer months. The vents perform two main functions;

Maintain Air Pressure

Air is motionless when there is no external force like blower fans to move it. Air conditioners work by drawing air indoors, cooling it, and then sending the cold air back into your rooms, gradually lowering indoor temperature.

However, this means that your rooms go through phases of temperature imbalance as the AC pulls and pushes air into the home.

The vents are a standby mechanism to maintain indoor air pressure balance to fill any void. Unfortunately, the supply register won’t improve your heating cooling system efficiency. The belief of improved energy efficiency by closing the supply register is very different from reality.

The return register that draws air out of a room remains open. As the air leaves a room, lower air pressure is created. As the room gets depressurized, air infiltrates from outdoors through small holes, cracks, or gaps.

You can use window treatments to maintain the indoor temperature or leave the doors to all the rooms which are too warm or cold open for air to distribute evenly.

Preserve air quality

You’re likely aware that air conditioners rely mainly on filters to remove debris from the air indoors to keep the air in your home healthy and safe. However, the filter doesn’t work on its own.

Instead, HVAC systems count on the vents to help out. How? By allowing the AC to bring fresh conditioned air into the house directly. Additionally, opening the vents allows stake indoor air (full of smells, airborne dust, and allergens) to exit your home.

Where are the Aircon Vents Located?

Air vent location varies from one HVAC system to the next, depending on the HVAC system type. Window ac system vents are the easiest to locate as they’re found on the device.

Look around the bottom left or right, and you’ll find the louver system and lever to control the vents. Wall HVAC systems have similar vent systems.

Portable AC vents are also not too difficult to find. You’ve found the vent if you find a sizeable hose running from the portable AC to the outdoors through the window.

Unfortunately, central HVAC system vents can be slightly different because the installation locations vary. Most people prefer ceiling-mounted vents for practicality, but floor-installed and wall vents are also very common. Furthermore, you may need to check all the rooms, including unused rooms, as some homes have air vents in each room.

Consider installing a ductless heating system if your home uses a central HVAC system. You can effectively maintain different zone temperatures with the zone temperature control system.

It gives you the chance to divide the homes into several different zones, each with its own temperature control as there will be separate heating and cooling system.

Should I Leave my Wall Vents Open or Closed for Temperature Control? 

HVAC system air vents should be open during the summer season, though you’re allowed to open the vents during the off-season.

The following are the pros and cons of opening or closing air vents during the summer season.

Pros and Cons of Opening Aircon Vents 

As we’ve said, you should keep your AC vents open throughout the summer season, even though it comes with a few drawbacks.


  • Remove stale air: Opening your HVAC system vents enables the AC to remove stale air, such as bad odors, from your home, leaving your rooms healthier and more comfortable.
  • Bring in the fresh air: Leaving the vents open also helps draw fresh air into your home, improving indoor air conditions.
  • Ensures indoor air pressure balance: Pressure imbalance in the home is associated with multiple challenges, such as back drafting. Leaving the vents open helps address this problem.
  • It’s good for your AC: Drawing fresh outdoor air into your home is good for AC functioning. For instance, it takes the pressure off your filters. Of course, it also reduces the risk of dust buildup with the AC.


  • It may take longer to cool your home: Letting the hot outdoor air enter your home via the vents can negate air conditioning gains, often leaving you with a sweaty home for longer.
  • Risk of letting airborne germs into the home: One of the reasons people keep the doors and windows shut during air conditioning is to keep out airborne germs and other organisms. Open vents provide a window for the same organisms to flow into your home.

Should you Close your HVAC Vent to Control Temperature 

Homeowners typically close vents in an attempt to redirect air away from unused spaces. This belief that they should be closing air vents and only opening them when the need arises will simply push the air onward to other parts of the home, improving energy efficiency.

However, the reality is that closed vents cause an imbalance of airflow, leading to too much airflow hence increasing heating costs as well as cooling costs.

However, This approach, too, has many advantages and disadvantages.


  • Keep airborne particles at bay: One of the biggest advantages of keeping your HVAC system vents closed throughout the summer season is that it helps you keep at bay dust, pebbles, and allergens that would otherwise enter the house through the vents.
  • It may be good for your power bills: Yes, the air from outside the house is typically fresher than indoor air, especially after recycling indoor air for a while. However, isn’t it the same warm air your AC works so hard to remove? So, why draw it into the house? It would only force your AC to work harder.

Why Closing Air Registers is a Bad Idea

  1. Closing air vents will increase your electric expenses: Incredibly, keeping your AC vents closed during air conditioning can also increase utility bills. It’s a dilemma because doing the opposite can also increase air conditioning bills. The good news is that you only have to worry about high bills if your air duct leaks. Closing vents increases pressure in your system blower, increasing the amount of conditioned air that gets wasted via duct leaks, thus more energy costs.
  2. Closing AC vents makes you less comfy: This happens in two ways. First, closing ac vents means blocking out valuable fresh outdoor air. Instead, you’re forced to rely exclusively on recycled indoor air. The air can become very stale very first. It may also become unhealthy. Secondly,
  3. Closing AC vent will damage your air conditioning system: There are two types of blower motors you could have include: ‘PSC’ blower motor. The PSC blower motor only blows at a fixed speed and can’t ramp up to overcome extra pressure from closed vents. Closing vents usually causes PSC blower motor fans to slow down their speeds due to high pressure; hence you’ll get less cool air from the HVAC system if you close ac vents. The evaporator coils can freeze over and, at some point, ruin your compressor. The evaporator coils are filled with cold refrigerant that sucks in heat from your home. Regardless of the air pressure present indoors, a fixed motor will maintain a steady rate while the variable motor automatically adjusts itself depending on the pressure it will sense. EMC Blower motor can readjust their rate according to the job required. Closing vents when using EMC blower motor won’t make you less comfy. If you happen to own a fixed motor system in your home, you ought to expect it to function harder to redistribute and move air through the available limited spaces.
  4. It can be bad for your AC’s health: Reduced airflow in the home can quickly result in less hot air flowing across the condenser coils. This creates a massive risk of AC freezing as the extra cold refrigerant coils need heat to prevent the lines from freezing.

Should my AC Vents be Open or Closed?

Generally, it’s best to keep your HVAC system open for the duration of the cooling season. Although it opens a window for outdoor dust and debris to enter your home, impacting indoor air quality, you can always count on your AC internal dampers to consistently trap the airborne particles and eventually eliminate them from your indoor air hence controlling the quality and air volume.

Doing the opposite (closing vents) comes with a few advantages, including the potential for lower energy bills. However, the disadvantages are grave. It’s bad for the AC, bad for your energy bills, and bad for your health.

How to Open and Close Air Vents 

It’s very easy to open and close your AC air vents. However, it also depends on the type of air conditioner.

  • Older aircon systems: Check for a louvered section around the bottom left or right (it’s mostly on the right). Below the louvers, you’ll find a lever that moves left to right or up-down. In most cases, pushing the lever left or down closes the vents while pushing it right or up opens the vents.
  • Newer aircon systems: Check the control panel for an “EXHAUST” knob or setting. Alternatively, check the “venting” section of your user manual for the name of the setting. Engaging this setting opens and closes the vent.

Remember, however, that not all air conditioners have a vent setting. Many modern units, for instance, use other mechanisms to keep indoor air fresh.


Air vent open or closed? 

Typically, the vents are open if the wings are horizontal (in the same direction as the ducts) and closed if the wings are vertical. You can also tell by the position of the lever/vent switch.

Do mini split air conditioners have vents? 

No, mini-split air conditioners don’t have air vents. The reason is to avoid energy losses associated with open vents. Instead, they cycle indoor air only.

What is vent mode in an air conditioner? 

Vent mode on an AC means the AC works as a fan and does not cool air indoors. It’s only circulating air to keep your indoor air fresh. Vent mode is valuable when it’s fairly cool inside the house.  

When should you open and close air vents? 

Ideally, you want to keep the vents open as much as possible during the summer season. However, feel free to close them three-quarters of the way if you’re worried about high energy bills.

Does closing aircon air vents save energy? 

Not necessarily. Closing the air vents doesn’t save energy and actually does more harm than good. Although it keeps out hot air that would typically cost more to cool, closing the vents can worsen indoor air condition, forcing the AC to work harder to keep indoor air fresh.

Should I close AC vents in winter? 

Yes, if the vents are built into the AC. However, you need a few open vents for central HVAC systems to promote return airflow. So, close the upper vents but leave the bottom vents open.

Should basement vents be open or closed in the summer? 

You can safely close vents in the basement during summer. On the main floor, you want to keep the vents open throughout the summer to promote return airflow.


Now you know whether to open or close your AC air vents. Generally, you want to leave the vents open as much as possible during the summer months for fresher indoor air and to promote return airflow. However, you’re allowed to close the vents partially during the winter months.

Give us a call for further inquiries on heating, cooling, and plumbing services. You can be sure we will give you practical and affordable solutions. By offering you exceptional and honest services, we can guarantee your satisfaction.