cab pressure- ac/ heat door vents

[vtwinsport]

Does anyone know if the door louvers at the bottom are there for a reason. I'm wondering about sealing them to keep out the cold/hot and make the cab warmer in winter and ac better in summer.
If the cab is anything like a house, I've heard that there has to be a return air vent (in trucks case, a vent to the outside), to cool or heat properly due to air being forced into room (cab), and if the return (vent) is plugged the room (cab) pressure builds up and the heater/ ac literally stops pushing in any more air.
Any thoughts?
thanks.

[vtwinsport]

Follow up question to the one above.;
Does the cab draw air form outside when heating or cooling? Or, does it pull air from within the cab to push over the heater core or ac core?
thanks.

[D13]

They are pressure relief valves.
When you slam your doors they vent the pressure to decrease door closing efforts.

Also they provide flow thru ventilation to prevent CO build up (a federal requirement by the way) and allow air to be displaced by the hot/cold air you are pumping in.

Blocking them will decrease air flow into the cab from the HVAC and will result in decresed and uneven heating / cooling.

The input air comes from outside, at the base of the windshield.

[James McClure]

D13 is right 100% with this little added "tweak". IF, a vehicle has A\C, then air can be recirculated without any fresh air from the outside getting in IF, A\C is on and set to recirc. Doesn't matter what temp is set at. IF, controls are set for normal A\C, heat or vent, air will be fresh. Leave door vents alone. The amount of air that gets in there isn't going to effect A\C or heating systems very much. Jim

[vtwinsport]

Thanks allot for the info. I figured there would be a good reason for the vents but didn't know what that was. I'll leave em as is.

[badblu97]

OK, so now I have a question. I totally removed all the A/C so I could lay out. Im sure I will install a vintage air or something similar, but really wanted to clean up the doors visually. Anyone see any real problems arising?

[Captkaos]

Those vents have rubber pieces (or suppose to) that allow internal pressure out but not external pressure in.

[78 Chevyrado]

With the vents blocked your ears will pop everytime you shut the doors with the windows up.

Plus if you run Max AC all the time, the AC pump will run constantly, wasting gas.

[74 C-30]

i rode in a 88 truck with sealed vents and good weather stripping and he had to roll down the window to shut the door or else it wouldnt shut tight due to air being slammed in