Many people didn't have candles because they cost too much, but they would often have fires and in the long dark evenings their houses would have looked quite lovely lit by firelight.

Many older people will remember coal fires in their houses. (People still have them but they are much rarer now.) Before the invention of TV it was quite common just to sit with no lights on and look at the flames. Fires in medieval times were mostly built from wood, sometimes dried dung or straw, some places used peat which also burns well. Very occasionally people might have used coal, but many poor people would not have had such easy access to this as to wood. 

Here  are a few images placed into a flash movie of a fire in a cruck timber open hall house. It is rather  jumpy because there are only a few images and the very short animation is moving at less than 1 frame/second. 

The windows would usually have been shut late at night, but in the evening people would probably have waited until the very last moment there was any light until they pushed the wooden shutters across.

Here is a larger static image.

These images take advantage of 3ds max advanced lighting so each image takes quite a long time to render. If I get time I'll render a panoramic view of the living room.