4 briquettes will get a typical 6kw wood burner or multifuel stove Hot rapidly.Form a triangle and pop a fire lighter in the middle and light,then place the fourth on top and like magic an almost instant fire.No flaking, no mess, not coal but nearly as hot as coal and clean hands.Quick to get your room  warm, easily controlled burn so you can get that room to the right temperature without opening all the doors and windows.