[djmcmath]

The existing heating system has a pump. When the thermostat says it's cool enough, it fires off the furnace and a pump at the same time. The existing cooling system is just window AC units.

So the problems with radiant cooling ... condensation is definitely an issue. Drip trays are an ugly solution, but it'd be the only real option. Blech.

Temperature requirements? Hmm, good point. A rough approximation of the surface area of the radiators says I can get a delta-T of about 20C, which would mean I'd need to fill the radiators with water at something like freezing in order to maintain something like room temperature in the space.

Ok, so maybe not such a good idea.

Thanks for the feedback.

Dan