If you really want to keep warm during the coldest months, count on the ingenious three-layer system. A layer of air is warmed up by your own body heat between each layer. Just like your house, you create the ultimate insulation.
Belgium is not known for its extreme winters, but it does experience a cold snap once in a while. You don't need extensive collection of winter equipment to prepare for those rare moments: these handy gadgets will be sufficient.