What’s the right volume of air out of a vehicle’s vents?

automotive A/C ducts

Automotive in cabin comfort.

Air is a fluid just like water. It flows from one area to another because of a difference in pressure. Nowadays automotive comfort quality is rated for noise and vibration and the interior sound levels has become a major target of car companies.The blower motor is in charge of moving fresh outside air or recirculated in cabin air through the evaporator core, heater core and to the a/c ducts attached to the hvac case then to the vehicle in cabin compartment. Blower motors are mounted between the air intake and the heat exchanger a/c component and their function is to move air as efficiently and quietly as possible.

Hvac case air flow.

The movement of air inside the hvac box flows from a higher pressure zone to a lower pressure zone. In the air conditioning plenum the blower motor creates the higher pressure and the design of the distribution chamber of the hvac case and cabin compartment permits the pressurized air to expand creating the lower pressure zone smoothing and guiding the air flow.

Air conditioning noise.

Air is forced to pass through the in cabin air filter where it is purified from road dust, moisture and other contaminants. Pressure loss is one of the major characteristic which will ensure a smooth flow of air inside the HVAC system. Airflow, temperature and pressure are interrelated and changing one parameter can affect the others. Too much pressure loss will result in less amount of air in the outlet and less pressure loss will disturb mass distribution and temperature distribution.

The position of the evaporator and heat exchanger play a major role in pressure loss. Any sharp edges or turns can create noise and vibrations can propagate noise from one part of the system to the other.

Hvac case manufacturing.

Injection molding is a manufacturing process for producing air conditioning boxes and air conditioning ducts, from both thermoplastic and thermostatic plastic materials. The hvac case holds the evaporator core, the heater core and the doors that direct the air inside the case towards the different dashboard outlets. In the main distribution chamber of the hvac case the air gets distributed by doors actuated by cable, vacuum or electronic control actuators. Part of the mass of air flows through the evaporator core and the rest bypasses the heater core and goes directly into the main chamber of the system. Every auto heating ventilation air conditioning case has a drain tube, in charge of draining the water condensation that occurs on the face of the evaporator core out to the underneath of the vehicle.

A/C head control air flow setting.

The air speed and air flow volume is going to vary depending on heating ventilation air conditioning case and ducts design. Usually the face vents mode is the one allowing the larger mass of air flow because of the bigger diameter of the ac ducts. Selecting foot mode or dividing the flow of air between face and foot it’s going to decrease the volume and speed of air coming out from the selected vents.

Free Estimates.

If you feel that the volume of air flowing out from the dash vents has considerable decreased give us call at (786) 483-9406 Auto A/C Repair, for a free anemometer test against manufacturer specifications and an entire a/c system check up. Our certified technicians will come to you with accurate information and the right tools and knowledge to get the job done right the first time.