[daveyd]

First of all, I am a total newbie when it comes to HVAC so please bear with me

I am building a room in my basement and want to heat/cool it. I have a forced air system with central air and gas heat.

My trunk goes from larger ducting to smaller ducting...I guess that is normal?

The smaller ducting in the trunk is mostly in the room I am building. There is no space in the top of the trunk to tap into to run a vent into the room.

My question is, should I tap into the side or the bottom of the trunk? If so, where in the trunk should I tap into..beginning, middle, end? If I do tap into the side or bottom, how much airflow will that take away from all the other vents that are coming out the top?

 

[johnnyboy]

As the duct size decreases, the air velocity increases. Makes for more efficient air exchange

It doesn't matter where you tap in, your small room vents will have dampers, you'll just have to spend a few days to find a comfortable setting.

 

[daveyd]

As the duct size decreases, the air velocity increases. Makes for more efficient air exchange

It doesn't matter where you tap in, your small room vents will have dampers, you'll just have to spend a few days to find a comfortable setting.

So tapping in from the bottom or the side of the trunk shouldn't matter? What about decreasing the airflow to the existing vents?

 

[beenthere]

What ever air goes to your basement is what ever air any registers past that point won't get.

How well do the rooms past that point heat and cool.
If they over heat, and over cool, your fine.
If they under heat or under cool, you got a problem.

Not as much in cooling. Since basements don't take much to col them.

 

[Yoyizit]

A variable speed duct booster fan should give you some latitude in duct design, location, etc.