Is radiant floor heat adequate as the only heat source?
I am planning a gut and remodel of the only bath in my home. The info I have found here has been invaluable in helping me make the myriad decisions that come with such a process. The bath dimensions are 7' wide, with one exterior wall having a new Andersen window, by 8' long; not quite 8' ceiling. 3' along the long wall is not inside the footprint; it's a hall-entry linen closet, and the remaining 5' on that wall is taken by the alcove tub. This leaves about a 4x8 floor surface. There will be a 3' long vanity along the wall opposite the tub, as well as the toilet.
I would like to remove the cast-iron radiator and rely solely on electric radiant-floor heat, but have gotten some feedback that there won't be enough floor mass for that to be as effective as I will need in the winter (I live in Zone 5 in the Northeast.) Since the rest of the house is heated with cast-iron baseboards, my plumber advises that to maintain the same heat-retention properties, I would be best off replacing the vertical-fin radiator with a 4ft length of cast iron.
Finally, I'm replacing rectified porcelain mosaic tile in the bath with marble basketweave mosaic. I never found the porcelain to be extraordinarily cold underfoot; will the marble be any colder?
Has anyone here relied solely on in-floor heat in the northeast with a similar footprint? Should I plan on doing both in-floor as well as baseboard? Thanks to all who can share their experiences!