Gas and Oil Home Heating Furnaces - Heat vents in basement

I have a unfinished basement in a townhouse, about 25 ft by 60 ft with one wall to the ground, one with a sliding glass door and two connecting to the other houses. I had planned to eventually finish it off. However, I now have two of my older kids living down there and would like to have heat for them. Except for two "rooms" - just walls, everything is unfinished. There is complete access to the a/c / heat venting system, but no actual vents into the basement.

I live in the Mid-Atlantic region, so it gets cold in the winter. The basement says pretty cool in the summer, so I am not really worried about the a/c. We have a heat pump. The basement ceiling/first floor is made of wooden truses(?) so it will be easy to run anything I want - no need to cut openings.

I figure I can cut a few holes into the venting system and stick vents in them to allow hot air into the basement, but what are the rules for this? Can they be in the main vent lines or do I need to add a secondary line and then vent off of that? Can the vents be directly down from the vent run or do I need to run something from the side of the run and then down? How many vents and how big? Since I will eventually finish off the basement and the venting system hangs about 2 inches away from where the finished ceiling will be, should I just put the vent into the current venting "pipe" or should I bring it down the 2 inches now? If yes, how?

We currently use two of the oil filled electric radiator type heaters, but I am concerned about safety and expense. Am I better off just comtinuing to use these heaters than trying to heat the entire basement?

shinrich:

It would most likely work out just fine connecting to your existing furnace.

There is a problem in that enough details are not known about your situation to give a detailed answer.

Do you live in the dessert or in Alaska? It makes a difference to our answer.

Read the announcement at the top of this forum, follow the instructions thoroughly, and get back to us.

I have updated the original post and would even like to ask the following:

Will I have to/should I created a vent into the return side of the forced air system? If I allow heated air into the basement, don't I have to create a way for it to escape/return somehow?

shinrich:

The exact volume of air that should be fed to your basement would be determined by a heat load calculation.

Winging it though, I would say that four - five inch round ducts may handle it.
Run the round duct off either side of the main trunk and elbow down. Put a balance damper in each one.
You say that you have a heat pump but do not say what form your emergency heat is. If it's electric then you could install a return near the furnace if needed.
I would try to do with out it at first and see how it works.

Because the basement is not insulated you may find that the temperature swings down there would be quite a bit larger than what you get upstairs because your stat will be sensing a more stable area.
Insulating the walls would make ducting this area work much better.

If you do decide to put in dampers, have a professional install a couple of trol-a-temps and a thermostat. These are motorized thermostatically controlled dampers. This would give proper temperature control to the space, and when the downstairs was satisfied, the dampers would close sending all the air upstairs.
:)