Good question – the robot I built at NASA was a beast – maybe 2m tall and weighted around 150kg. This was by far the biggest robot I worked on.
For home-based robots – they are generally below 1.3m tall. Some guys at Honda estimated that this was the optimal height. You dont want the robot to be too tall because it will take more energy to move and people might feel intimidated if the robot is bigger than they are. You dont want the robot to be too small or then it wont be able to do things it probably will need to – reach a light switch etc.
So the robots I make for use in homes are roughly the size of a small person – 1.3m. And they weight around 30-40kg.