Coffee123

Just came back from a service appointment, told them abt the issue where I would have AC/air blasting at the central area, but little to nothing near the foot bed. Tech tells me this is how Acuras are designed and I'm not convinced for a 50k car. The RDX is my first Acura so can someone if this is the case or have experienced this on the RDX before?

Thanks,

RDX-Rick

If you set the thermostat to a low temperature, while "Auto" mode is active, cold air will be sent to the face vents only, . This is because cold air falls due to gravity (cold air is heavier than warm air). If the cold air was sent to the foot level vents, it would just stay down at the foot level causing cold feet and a sweaty upper body.

If the thermostat is set to a warm temperature, the warm air will be sent to the floor vents. This is because warm air rises. By sending the air to the floor, it will rise, and distribute itself throughout the vehicle.

Cold air is not sent to the defroster vents on a hot day, because a cold windshield will produce condensation on the exterior surface from the hot/humid ambient air. Warm air can be sent to the defroster vents because it will help eliminate fogging due to the fogging on the cold windshield due to the humidity in our breath, or the moisture from the melting snow on our boots.

This information is true for all vehicles with an Automatic HVAC system. Of course in all Automatic systems, the driver can override where air flow is directed.

Coffee123

Thanks Rick, I should've been more clear that this only pertains to manual settings, not auto.

When I have it to the max setting and air directed to body area, it is strong but when I direct it to the foot bed, there's little to no air flow. Same thing when I have air directed to body and foot bed, I can feel it on the body but not on the foot bed. I just find it weird that there's such a huge difference in air flow intensity between body and foot bed when it's on max setting.

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RDX-Rick

I checked mine today. I set the fan at full speed, and found strong "forceful" air flow coming from the face vents. I then switched to the floor vents and reached under the dash with one hand to check that airflow. My first thought is that the pressure (or air speed) was much less than the face vents. I continued to reach even further towards the floor, and It feels like the vent is at least 6"long. If you consider the amount of airflow there is, multiplied by the square inches of the vent, it is probably equal to the airflow of the face vents multiplied by the area of those vents.

Consider the analogy between a garden hose which has a small discharge area, shooting out a stream of water 6 feet into the air. If we connect that garden hose to a fire hose, there will only be a dribble coming out the end of the fire hose. We know that the fire hose is delivering the same volume of water as the garden hose, but seems like a dribble when compared to the 6 foot stream from the garden hose.

My conclusion is that even though the air stream seems less intense, it is really the same volume of air being discharged. A side benefit is that the larger floor vents will let the air flow with less noise.

Bomboxmoa

Bump

rdx2403

AC set to auto seems to work fine on hot sunny New England days however airflow through side vents is limited.

subiefanIL83

Of all the cars I've been around in my family, the RDX has the quietest radiator fans I have ever heard. You basically have to have the hood open to hear. My Subarus were also pretty quiet. Same as the RDX when they were running at low speed and you had to be standing right by it to hear when then were running on high speed. My sisters Volvo you can hear a mile away. I wonder if the fans aren't pulling enough air over the condenser at times.

TheDatanator

they are indeed very quiet and you may have a point they may not be moving enough air to fully optimize the air-conditioning. The only time I noticed my radiator fan noises on my RDX was when I would pull in the garage and shut the car off and the fans would squeal to a stop lol three radiator fan replacements later they seemed to find fans that wouldn’t do this… Same thing with front suspension you never hear it until you hear the creaking like an old Buick going over speed breakers… But then again that was fixed as well two control arm replacements and both sides of the front struts replaced. But I digress…