I am interested in radiant heat.  I have a 1910 home w/ an unfininshed basement that would provide access to retrofit to radiant heat on the first floor.  The second floor of the home is a combination of radiator and baseboard.  Coud I do the retrofit, or would the higher boiler temp for the rad/baseboard prohibit me from doing it (I understand that the radiant system operates at a lower temp.).  Any thoughts would be appreciated.

You can do it with a little help.

Some of my sub-floor systems operate below and some above radiator or even baseboard design water temperatures (180°F). The design or operating water temperature is based on the heat load and potential output of the radiation.

If you use bare tube below the floor in a retrofit here in Minneapolis, expect to run it typical fin-tube baseboard temperatures in the coldest weather. With extruded aluminum emission plates, lower temperatures and better response time can be achieved without threatening the integrity of the finished floor.

Many of my clients install the panels and help me install the tubing and finish by insulating to spec.

It all starts with a room-by-room heat load analysis.