I've used thousands, of sq.m of the same; 'radiant panel' heating (hot water) at ceiling level is used a
lot in heathcare design - because it avoids having to try to clean HW radiators and all those fins in a clinical environment. And when you have control over other aspects of whole-building service-design choices-
esp heat recovery from ventilation- it can work better that one might expect. But I'd never choose it at home, however it is heated - and def not if electrical.
[PS they
do work even when just plain RAL 9010 white; despite what you might expect from Boltzmann's constant -simply because the panel temp is so close to ambient that the 4th power thing just don't matter
]
The big 'gotcha' with overhead low-temp radiant panels is having the primary heat source
above your head - that is
not the most perception-of-comfortable nor efficient way of doing things generally in living spaces. (works in the healthcare context I describe, because it is fundamentally a local top-up, not primary heating... once the fabric has settled into use)
In terms of perception of comfort, underfloor heating is
far better - have you thought of just using an electrical heating mat in the floor ? These can be be lost in the c.3mm adhesive bed for a ceramic tile floor, but can work equally-well under 'lino'/vinyl, with wood or even carpet - and provide better bang-for-buck overall comfort, for the same power input.
