If your property was built before the 1030s there’s a good chance it will be a solid wall construction. A good way to tell is by looking at the brick pattern. If you wall has lots of “end bricks” (which look like half bricks but are actually full, cross bricks which are laid to run from the front to the back of the wall) which are in the middle of the wall and not just around windows and doors then this is usually a reliable indicator. Typically the depth of a solid wall is obviously the width of a brick – around 9 inches.
“…the better insulated a property is, the less money will be spent on heating it.”