Potted orange trees?

Stacy&Jason

I really want a potted lemon tree now after the Apartment Therapy post.  She mentioned that orange trees need more heat...how much more?  I couldn't really find any information on this.

anneg

i'm in northern california and we have several potted citrus trees, including a meyer lemon, two blood orange varieties, grapefruit and lime.  i'm from pittsburgh, though, and i think if you brought the tree indoors for the fall/winter you'd be fine.  i think it definitely gets warm enough in pa during the summer to have a potted orange tree.  it's generally in the 40s here over the winter, so i wouldn't leave it out in temperatures lower than 40 degrees.  i don't know that it needs especially warm temperatures in the winter but it can't get freezing.