Grill Blocking: Does it help or not?

Ok, here's the deal.

Live in Houston, so it doesn't get real cold down here except for about two or three months out of the year. But I do travel sometimes to East Texas, and some times it can get pretty cold up there. 20 F etc.

I have noticed on the highway when it is close to 35 F and the engine is warmed up and has been running for at least thirty minutes or so that the cabin will be comfortable. Temp set @ 75 or 76 but once the air shifts to the vents on the dash (Auto mode with A/C off) that the air sometimes won't feel real warm. Both of us are kind of thin skinned, so we keep the temp set a little warmer than some do. Same in the summer, hardly ever have it on 74 or 72, usually 75 or 76. If I raise the temp, the air will warm up, so I figure it is working ok, just not sure...

I believe the system is full of coolant. No leaks that I know of. The heat works good like I said but once the cabin warms up to the setting on the MFD, it then settles down to a cooler air flow. Not much cooler, but not hot air like when it is trying to warm up the cabin after sitting for a few minutes.

I am curious if anyone else has noticed this or what. I also note if I run the system on recirculate then the windows will fog over since the compressor is off.

Any thoughts on this would be helpful.

For the record, I haven't tried blocking the grill yet. I don't have a Scangage so I am hesitant to block without a way of monitoring the ICE temp. No smart phone also. I have considered blocking half of the top but haven't done so at this time.

 

I think my main question is would it be normal for the air to feel cool rather than warm once the cabin has warmed up when the air is coming out of the a/c vent. It is NOT cold, nor is it hot. Just sort of like room temp.