I Am Cold

any suggestions on how to keep my flat warm on a budget? It is one of those kinds of tower blocks built in the middle of England in the 60s out of desperation for housing the poor so it doesn't retain heat well (the average temperature in the warmest room- the living room- is typically around 14 degrees c in the winter), has an old school immersion boiler tank thing and storage heaters that drink electric like an alcoholic drinks vodka. thanks in advance