[nascenta]

Hi,
Just wanted to contribute a few thoughts regarding the cost/benefit of radiant heating. The tearing up of the floor, putting down foam, pex etc. is an ideal. I've worked with customers that don't have that kind of money, patience whatever and have had great success warming up basements by doing two simple things.
1. Get the heat down to the floor. Often around here, the heating ducts in the basement poke out of the ceiling. The heat just stays high in this situation. Extending the duct into the wall to come out a foot or so above the concrete floor is the key. Best results come when there is concrete or the tile is the flooring since it can absorb the heat.
2. When insulating the walls. Go with 2" high density EPS attached right to the concrete (there are plastic anchors that are made for this, just requires hammerdrilling a narrow 2" deep hole in the concrete walls) or you can glue it. Next, put up a radiant barrier. You can get mylar stuff on-line or if you are really on a budget, just glue industrial sized aluminum foil to the foam using white glue. After the insulation you frame a thin wall against the foam to compensate for loss of floor space. (I use 2.5" steel studs and channel. A new wall is preferable to furring strips because foundation walls are rarely plumb and you need space for electrical and plumbing) The dead air space created by the thin wall allows the radiant heat in the basement to return to the wall surface making it feel warm.
These two things by themselves have turned formerly cold basements into cozy caves without tearing out the concrete.
I would suggest a relatively inexpensive experiment. If your heating ducts are coming out of the ceiling, extend them into the wall and out at floor and see how much difference that makes. It might be enough to give the feeling of comfort to the feet and you've saved yourself a ton of money and hassles.
YMMV.