How Strong Should Air Come Out Of Vents?

Here’s a quick guide on finding how strong should air come out of vents. Follow the necessary modifications given to increase the rate of airflow in your home.

How strong should air come out of vents? It depends on the system and settings as required by your house. Generally, the airflow should be approximately equal throughout the house. If not, you will feel that some part of the house is freezing cold while another area is warm. You can regulate the airflow inside the house with a reliable HVAC system.

How Strong Should Air Come Out of Vents?

The amount and rate of air passing through a spinning fan depend on multiple factors. The overall size of the room and the speed at which the air comes through the fan affects this. Consider a typical bathroom or a closet with dimensions 6×8 feet. This needs a fan that can pump air between 185 and 239 cubic feet per minute, based on EPA standards. Following the standard ventilation levels during both summer and winter seasons help secure your health. It also lessens the possible effects of allergies, asthma, and other breathing disorders. Maintain the room temperature inside the house between 65 and 75 degrees Fahrenheit in the winter season.

how strong should air come out of vents

How to Measure the Airflow?

The professionals measure the rate of airflow to determine how strongly air should come out of vents. The qualified air balancers use some measurement methods as described below.

CFM and Airflow Calculation

The experts use the CFM (Cubic Feet per Minute) method to measure the airflow in a room. This helps determine the safety and air exchange rates. You can measure the airflow in your room by following the simplified steps given here.

  1. Measure the length and width of your room to find the area. Then find the height of the room from the floor to the ceiling.
  2. Multiply the length, width, and height to calculate the volume of the room in cubic feet.
  3. Then multiply the cubic volume of the room by the number of times you want the air to exchange in an hour. 
  4. Finally, divide the answer obtained in the previous step by 60 to calculate the CFM value. 


Assume that the length, width, and height of a room are 13, 10, and 9 feet, respectively. 

The Cubic Volume of the Room=13ft×10ft×9ft=1170 ft3

Consider that you want to exchange the air inside the room three times per hour.



Use an Airflow Balancing Hood

This device can determine the performance of the HVAC system based on its airflow hood. It measures the volume of air coming from a diffuser to identify the areas with limited airflow. This helps in finding the right amount of air to pass into each room by testing, balancing, and adjusting the HVAC system.

Use a Non-contact Tachometer

This is also known as a non-touch or photo tachometer. It measures the operating speed of a specific engine or a system in RPM (revolutions per minute). This device comes in handy when you need to measure the airflow without contacting the surfaces due to safety or space concerns.

An Airflow Traverse

The airflow traverse uses a straight exhaust duct where you need to drill a few holes into the duct. Then measure the velocity of the air using an anemometer. These two measurements help determine the speed of the air in the duct. 

Static Pressure Kit

This kit includes a manometer, a hose, and a static pressure tip. Professionals use this to measure the static pressure to find out the CFM. This may be used along with some other devices to measure the airflow as required.

Why is the Airflow in My Air Conditioner So Poor?

Airflow issues are common in old HVAC systems and new installations. If you find that air doesn’t flow through the ducts as needed, check for the following possible reasons. In most of these cases, you can fix the issue yourself easily in a few steps.

Blocked Vents

The vent is the opening that allows outdoor air to enter the house. It is usually located on a wall, roof, or near the floor. Some vents have a closable damper so that the user can block the airflow when needed. So, as the initial step, check whether the damper is closed in your vent. It may be obstructed by some furniture or shelf, blocking the airflow. A blocked vent is probably the most common reason for an unresponsive air conditioning system. Also, check the vent for possible debris clogging inside and clear them out.

Closed Damper Valve

The damper valve inside the HVAC is responsible for regulating the airflow. It may block the path of air in a specific region to focus more on the room that needs more air. Damper valves are of two types; automated and manual. The automated dampers rely on a thermostat which is adjusted to the required settings. If your automated damper valve malfunctions, it is more likely to be due to a thermostat failure. If it is a manual damper, check whether it is left in the wrong position by mistake. You can use a lever to change the position of the manual valve.

Clogged Ducts

Sometimes, debris can find its way through the filters and settle inside the ducts. These particles stick to the duct easily with moisture or static pressure. The dirt builds up over time and may even attract pests into the ductwork. Check your ducts for possible clogs and clean them thoroughly. You can even consider hiring a professional to clean your ductwork as a part of the maintenance routine of your house.

Leaking Ducts

If there are no visible obstructions in the ducts, the next possibility is having leaks in the duct. Holes and gaps in the ductwork reduce the air pressure in the system. This leads to weaker airflow from the HVAC. Having a 20% leak in the duct makes the unit work 50% harder. Seal the leaks or install new insulation to fix this problem.

Flex Ducts

Your ductwork will most probably have some flex ducts if you have an attic. These are flexible insulated plastic ducts with wire ribbing. It is easily identifiable from the other pipes made of hard metal. Flex ducts are used mostly in areas where it is essential to bend the pipe. However, this flexibility can restrict the airflow if crushed or damaged. Sometimes, you may be able to get the duct back in its original shape. But if there are any holes or cracks, the best option is to replace the duct. Call a professional duct installer to cut out the bad section and fix a new piece of flexible duct to the system.

Restrictive Air Filters

Another possibility is the clogged filters cutting out the proper airflow. The air filters can get dirty over time if not cleaned regularly. Check the condition of the filters, clean them or replace them as necessary. Check the manufacturer’s recommendations to find a compatible model of filter.

Frozen Evaporator Coil

The evaporator coil is responsible for cooling the air in the HVAC system. It may freeze due to certain external conditions. You can identify that this is the case if you find water pooling near the indoor unit. Call a professional if you see any signs of ice build-up in the evaporator coil

How to Increase the Airflow?

Fixing the above-mentioned issues in the HVAC system will improve the airflow in your house. In addition to those, there are some other ways in which you can strengthen the rate of airflow. Try the following methods to optimize the airflow, but make sure not to have too much air coming out of the vent.

Use a Ventilator

Use an energy recovery ventilator (ERV) to increase the airflow and lower the humidity. It removes stale air inside and draws fresh air into the system. This reduces the stress on your HVAC system and boosts its efficiency.

Check Vents and Registers

Make sure that all registers are open and the damper valves are positioned correctly. In warm weather and hot seasons, you should open the registers on the upper floor and partially close those on the first floor or base. Do the opposite of this in cold seasons to regulate airflow.

Clean the Ducts

Cleaning or replacing the air filters is not enough in most cases. Clean the ducts thoroughly to renew the airflow system. This effectively solves the airflow restrictions in most cases.

Use an Air Cleaner

Try using a portable high-efficient particulate air cleaner (HEPA). It filters particles in the air that people release as they exhale, cough, sneeze, or talk. This keeps the air clean and is very helpful in preventing contagious diseases.

Regular HVAC Maintenance

Conduct regular inspections and maintenance in your HVAC system. This is the best way to prevent possible issues before they become major concerns. It also enables energy efficiency, and optimal air quality, and enhances the life of the AC system.

More Tips

Place the vents near an outside wall to increase the airflow by pulling in more air. Leaving more open space between the vent and the doors or windows reduces airflow into this area.

Place vents on different floor levels so that lower-level vents can draw air beneath the upper rooms and vice versa. 

Change the speed of the fan to support the existing HVAC system. Turn down the whole house fans when the AC is running to get more ventilation.

Try zoning systems if you have certain rooms in the house that don’t need regular cooling as the other parts. Talk to a professional regarding this and they will provide you with a suitable system with temperature control and efficient airflow.

Frequently Asked Questions

How Can I Tell if My Air Vent is Functioning Properly?

Inspect the air vents when your HVAC system is running. It is not a good sign if it blows out air with dust and debris. Uneven temperatures, inconsistent airflow, and condensation of moisture on the ducts are signs of a malfunctioning system. 

How to Check the Temperature of Air Coming Out of Vents?

Test the temperature on a day when the outside temperature is above 80 degrees Fahrenheit. Let the air conditioning unit run for about 15 minutes. Then place the thermometer on a vent and keep it there for about five minutes before you note down the reading. Place the thermometer on a return vent and do the same to get the reading. The air flowing out of the duct should be 14 – 20 degrees cooler than the air flowing in. Check the vent in each room using this method. If you detect any ducts with abnormal temperature variations, there could be a problem with the HVAC system.

How Are Vents Connected to the Air Conditioner and Furnace?

The vent is the hole that allows air into the house. Then it passes through the duct, which is a metal tube that runs from one room to another. There could be one or a few ducts inside the house. The bathrooms usually have separate ducts for heaters and fans as they require different temperatures depending on the time. The air conditioners connect to the vents to regulate the air indoors. The furnaces use metal pipes to conduct hot air. They are often made of black iron that doesn’t corrode easily. These pipes need insulation to keep the heat in without dissipating it to the cold air outside.

How Hot Should Air Be Coming Out of Vents Gas Furnace?

The air coming out of the furnace should be about 40° – 70° warmer than the air coming in if everything is in order. This increase in temperature is called the temp rise. High temp rise is often a result of an oversized furnace, undersized ductwork, or a combustion problem. An airflow obstruction could also cause rapid increases in the temperature.

How to Increase Airflow to the Second Floor?

Install a ceiling fan or keep the air conditioner running in fan mode to get more air circulation. Increase the size and number of return vents. Close vents on lower floors to improve airflow to the second floor. You can also try ductless air conditioning and a zoned HVAC system.


Weather conditions can affect the energy efficiency of the heating and cooling system of a house. However, temperature variations should not reduce the rate of air flowing out of the vents. If you need further clarification on the matter, contact your local professionals to find out how strong should air come out of vents. They will check the condition of your house and determine if there are any issues. Check your AC system regularly to ensure its efficiency for a long time.