SEAL THE FURNACE
ISSUE: The seams on most furnaces are not adequately sealed, allowing air to escape.
SOLUTION: Although not a common feature in most South African homes, some houses do have central heating systems. To improve efficiency, all joints should be covered with a layer of duct mastic, then a layer of fibreglass mesh, then another layer of duct mastic. All three can be applied at one time. There’s no need to wait for one layer to dry before putting on the next.