basement air registers - open or shut during winter

[ciltep]

Quick question. With a forced air system in a home with a main level and an unfinished basement, but one that does have supply runs and registers installed, should the basement supply run air registers be left open or shut during the winter?

My father-in-law says shut since you don't want to heat space that you aren't currently living in. My father says open them because it will make the upstairs feel warmer as the heat that is poured into the basement rises. Both seem to make sense. I don't want to waste energy, but I also want the most comfortable solution. Right now, they are closed and I think my floors feel cool.

Any thoughts or suggestions? Thanks for the advice.

[propmanage]

Design would call for them to always stay open but most likely the system was never balanced any way. A lot of people just cut back so they maintain a reasonable temperature in the unfinished basement and it will increase the CFM to the other sections of the home. If you have problems keeping the house warm you could try closing them off. Each house would require a different application due to the set up. Test things out until you feel you have it right.

[ciltep]

Thanks for the info. Right now they are closed and I feel like the floors upstairs are cool. I'll try tweaking it.

Unfortunately, I think my whole system is probably not designed real well. I've posted in other forums and have been told that

1) My furnace is over sized - 105k btu single stage output with 92 AFUE
2) My trunk ducts are undersized - trunk ducts are 8x14.

What's really sad is that the house is about two-months old. I'm considering redoing some things, but I'm a novice and don't really know where to begin.

Basically, my furnace seems loud, the house doesn't feel particularly warm, and that's with the temp usually set at 70.

I may post a post with all my particulars and hope to get some advice from you folks. This is a great forum--lot's of good advice in here.

Thanks.