Usually these small filtered vents help improve air quality since the air outside is typically fresher than the air outside.
Furnace outside air intake.
However this does not mean that your home does not need a fresh air intake just because you have a high efficiency furnace.
If your furnace draws combustion air from inside the house you are using air that you have already heated.
Typically the fresh air intake will be located in your attic or ducted to the return side of the home s central air handler.
Locate a spot for the fresh air intake hood on the outside of the home.
If return air comes in at the bottom it is an updraft or upflow furnace.
Ways that outdoor air can enter a home.
Baseball is like church.
Many attend but few understand.
The air that is surrounding your outside unit is just outside air and the air coming from your inside unit is inside air.
Through open windows and doors which is known as natural ventilation.
Through mechanical ventilation devices such as bathroom or kitchen fans that vent to the outdoors or heating ventilation and air.
Unfortunately the fresh air intake you have described is the second type and does not provide direct combustion air to the furnace room as it is directly connected to the return air plenum for.
There are alot of gas furnaces in this neck of the woods that have no outside air intake granted these are mainly older homes.
The indoor portion of your unit has an air conditioner return air intake usually located on the ceiling.
You don t want to bring any of those exhaust gases back into the home heating system.
But during a wildfire they can pour unhealthy air into your home s interiors.
To keep smoky air outside close the intake using the damper.
It is much more efficient to use outside air for combustion air.
How your ac unit works.
There is no chimney in the house gases are vented through pvc pipe out the walls seperate 2 for water heater and furnace has 2 4 pvc plus this 6 outside air intake.
If airflow comes in from the top it is a downdraft or downflow furnace.
Since high efficiency furnaces draw air directly from outside the furnace itself does not require a fresh air intake in order to replace inside air that otherwise would have been drawn from the room the furnace is located in.
That air is replaced by cold outside air that will then need to be heated.