What is the outside air intake on my HVAC system?

Author: Jasen Graham  |  Last update: Friday, August 29, 2025

What is HVAC Fresh Air Intake? The fresh air intake is an opening through which outside air is drawn into the building. This may be to replace the air in the building that has been exhausted by the ventilation system or to provide fresh air for the combustion of fuel. Abbreviated FAI.

What is an outside air intake?

A fresh air intake is a duct that brings in outside air to the furnace. This air is then heated and distributed throughout the house. The fresh air intake is important because it ensures that the furnace has access to fresh air to use in the combustion process.

Do I need fresh air intake on my HVAC system?

With a conventional furnace, a fresh air intake filter is needed so that the furnace does not pull air from what we call “unconditioned” places in the home where air quality is poor. This includes the basement, crawl spaces, attics, even dryer vents. With the filter, the replacement air is drawn from outside the home.

Why does my HVAC system pull outside air?

When you set your HVAC to “fan” mode, it circulates the air that's already inside your house. However, some systems have a fresh air intake that can bring in outside air when the fan is running. If you have such a system, it might pull in some outdoor air to improve ventilation and indoor air quality.

What is the outside part of HVAC called?

The outside unit of an air conditioning system is often called the condenser unit because the condenser plays a key role in how it works. Check out all of the most important parts.

Does my furnace need a FRESH AIR INTAKE?

What is outdoor air in HVAC?

Outside air is air that is usually brought in by a HVAC unit to help pressurize the building or provide free cooling in the case of an economizer on an RTU.

What is the outside part of a split system air conditioner called?

Most air conditioners have an outdoor unit called a condenser unit. Whether you use a split system, heat pump, or central AC system, they all use an outdoor unit to keep the warm and cool air in your home.

Why is there very little air coming out of vents?

**Clogged Air Filter:** A dirty or clogged air filter can restrict airflow, causing reduced air output from the vents. Check the air filter and replace it if it's dirty or clogged. 2. **Blocked Vents:** Make sure that all vents are open and unobstructed.

Why wont my central air unit kick on the outside?

This could be due to a bad electrical connection, an overheated motor or a short circuit. To check the circuit breaker, locate it in your home's circuit breaker box and look for a tripped breaker, which will be in the center position between on and off. Reset the breaker and see if your AC works again.

How do I find my HVAC fresh air intake?

The best way to find fresh air intake vents is by looking near furnaces and other gas appliances. They usually appear as grilled vents, but they're not always out in the open. If you don't immediately see it, the intake may be behind an appliance, a closed door, or an intake cover panel.

What is the difference between return air and outside air?

When you run the air conditioner, you get cool air from a supply vent. A return vent sucks in, or returns, the air back to the HVAC ductwork system. Many HVAC systems do not get their air from the outside. Instead, they get them from the inside the building through a return vent.

Can I turn off my fresh air intake?

Sliding the dampers manually into a closed position. Turning off a fan switch if the intake is fan-operated. Using the HVAC control panel to automatically close the damper. Turning the lever or knob on an outdoor or indoor unit that says “fresh” or “air intake”.

How often should fresh air intake run?

Your air intake is designed to run constantly, brining in a steady flow or fresh air. Some models are equipped with temperature and humidity controls that will turn the unit off if the air coming into the home is too cold, too warm or too humid.

How to clean HVAC intake?

  1. Step 1: Prepare for the Cleaning Process. ...
  2. Step 2: Remove Air Vent Covers. ...
  3. Step 3: Vacuum the Visible Dust. ...
  4. Step 4: Brush Away Stubborn Dust Buildup. ...
  5. Step 5: Clean with a Damp Cloth. ...
  6. Step 6: Address the Duct System. ...
  7. Step 7: Check for Mold and Unpleasant Odors. ...
  8. Step 8: Reinstall Vent Covers.

What is the difference between air intake and air filter?

The majority of the cold air intake features an exposed conical filter. These air filters are engineered to draw more air than the factory air filter. Hence, the primary difference between a cold air intake and a stock air box is their filtration capacity and the intake air flow rate.

Why is my outside unit not running but inside is?

The outside unit may not run if it's shut off or the safety switch is engaged. Worn parts, like fan motors or contactors, can prevent the unit from turning on. Debris inside or outside of an AC unit can keep it from running properly. If a bad compressor is to blame, you'll need to install a new cooling system.

How do I get my outside AC unit to kick on?

Outside AC Unit Won't Turn On? What to Do Before Calling for Repairs
  1. Make sure the thermostat is set to COOL. ...
  2. Check the emergency or shut-off switch. ...
  3. Check the inside unit's power switch. ...
  4. Look for a blown fuse or tripped circuit breaker. ...
  5. Look for problems with your condensate drain line. ...
  6. Try resetting the air conditioner.

Why won t my central air kick off?

Malfunctions affecting different system components can prevent the conditioner unit from shutting down as expected, such as a clogged air filter, a frozen evaporator coil, a faulty electrical relay switch, a dirty condenser coil, a constantly blowing fan, a bad thermostat, low refrigerant, and other HVAC system repair ...

How do I know if my air vent is clogged?

Signs of an air duct clog include: One room in your house is hotter than all the others. Dirty air coming from vents. Unusual spikes in electric bills.

Where does return air go in the HVAC system?

Return air vents connect to your return ducts, and they're typically larger than supply vents. Again, depending on the design of your ductwork and home, HVAC return vent locations vary but are often in central areas, kitchens, bathrooms, and pollutant-prone areas so as to best collect stale or dirty air.

What is the most common cause of poor air flow in a duct system?

Obstructed Vent

One of the most common causes for poor airflow is a blocked vent. To properly heat or cool your home, the air needs to be unobstructed. To see if there are any blocked vents, look by the baseboards or on the ceiling. Furniture, bedding, and the vent damper could all be possible obstacles to the vent.

Does the condenser fan always run when the AC is on?

The answer to this is no. The AC fan does not run non-stop. It's intended to cycle on and off, depending on the needs of the HVAC unit. That being said, there are some situations where it stops unnecessarily, and that's where you may have an issue.

How much does it cost to replace a condenser unit?

On average, the cost of a new AC condenser and installation can range from $1,500 to $4,500. However, it's best to get an accurate estimate from a licensed HVAC professional in your area to get a more precise cost.

Do split system air conditioners use outside air?

Well, because split systems are completely sealed systems they are never bringing outdoor air into your home. By recycling the indoor air it works by improving the indoor air quality and pushing hot air out. How does it do this? Keep in mind the important role filters play in keeping your air clean.

Previous article
What is the most effective natural mold killer?
Next article
Can you put rugs on luxury vinyl plank flooring?