OK, sorry I derailed this topic. Sounds like PK does have a power source so let's get back to Perchking's question now.
Tom's comment is a good one and something I was thinking about as well.
Would Perchking have to keep the cabin at comfortable temps all winter long? How fast will a system like this recover if left at a low temp like between 40-50 degrees? Even if augmented by a wood stove to heat it up once you arrive, would the temp of the in floor system recover from say 45 degrees to say 68 degrees in 2 days? If not, maybe Perchking plans on leaving the in floor system at a low temp all winter just to keep the cabin from freezing and supplementing with some other heat source?