Question

Room heaters are usually installed at the ground level

Answer 1

Answer:

As you know hot air Rises up and cold air settles down so room heater is placed near to the floor so that the heat can move uniformly from down to up.

So by heating the cold air at the bottom it is more efficient and creates an updraft and circulates the air better than if it were heated at the top.

Answer 2

Answer:

Cold air sinks. So by heating the cold air at the bottom it is more efficient and creates an updraft and circulates the air better than if it were heated at the top.