Radiant Cable Heating

We've been looking into electrical radieant cable heating. The cost is about $300 per room, and offers a steady even heat across the floor. There are so many concerns. I have the corn heater, but that isn't equivelant to a furnace.

My problem is - our house was never designed to allow room for heating ducts. I've been looking into a few different layouts and projects.

I have some questions. Like, do the cables need to be laid close together when laying the cable. It will cost me about $2000 for the cables...but any other heating will cost up to $8000. My question is - how much will it cost to heat the house. I do not need to put cables in the halls, stairs, etc.

I'll keep you up to date.