Energy star has found that new furnaces often do not perform to their rated efficiency with.
High efficiency furnace fresh air intake.
Traditional gas fired forced air furnaces produce hot combustion exhaust gasses and therefore need metal vent pipes or chimneys.
However without a quality installation the furnace may never deliver its expected energy.
A heat recovery ventilator or hrv is an optional device separate from the furnace that works as an air to air heat exchanger.
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.
The pvc pipes are used for air intake exhaust gas and to remove the corrosive condensation resulting from the combustion process.
See reference 5 in sealed combustion units as most high efficiency furnaces are.
If a furnace has an afue rating of 90 percent or greater it is considered condensing.
Other aspects of high efficiency furnace venting.
In these types of furnaces the exhaust is vented outside via a pvc pipe.
When a home is well air sealed or tight it may warrant an optional fresh air intake that pulls air from outdoors into the furnace and prevents partial vacuum situations.
Fresh air intake for high efficiency furnaces i am a homeowner in new jersey who recently had a carrier infinity ics modulating gas furnace model 58mvc installed.
In contrast modern high efficiency condensing furnaces exhaust much cooler gasses and need only plastic pipe materials such as pvc cpvc or abs for their exhaust vents.
Some high efficiency furnaces also include a plastic pipe for intake area and all types use a third plastic pipe to drain away the corrosive condensation resulting from the combustion process.
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.
However this does not mean that your home does not need a fresh air intake just because you have a high efficiency furnace.