Calculate the kind of power you need to warm a 5x8x2.5m room by 8C and you get a feeling of what is just being wasted.
I bet only a fraction of that 8C rise is down to electrical stuff... there is a much bigger energy-emitter in the room - YOU!
A human being emits a lot of heat! Try putting a hat & gloves on, a big coat and covering as much skin as possible... I bet you'll find your room will barely rise in temperature at all! :-)