Please be carefull if yiu are considering installing the very low wattage electric panels, sub 500w that are being questionably promoted here, by a first post from a new member
I can tell you from a professional view that you need to calculated, based on the size of the room, the total watts that you require to properly and cost effectively heat a room, typcally for a standard room at least 2kw, whixch would mean at least 4 of these units which do not include any timers or method to control the heat output
It is far more cost effective to spend more money up front buying a grade A +2kw unit which includes a sophiscated timer and room stat and will not use any more electricty than the 4-5 flat panel units that you would have to fit to get the same level of heat output
These units work well in small rooms like bathrooms with the addition of a socket timer
Vist the local DIY shop like Leroy Merlin for more details