Step 1 Measure the mirror and mark the area on the wall.
Step 2 Mount a flex pipe in the wall from the mirror to the nearest connection box.
Step 3 Cover the marked area with tile adhesive by using a toothed spatula. Remember to buy the sort of tile adhesive which does not attack the mirror - your local DIY store can help you.
Step 4 Press the mirror heating mat into the tile adhesive - make sure it is even and fixed. Then cover the mat with tile adhesive - make sure the surface is smooth.
Step 5 Put the connection tail of the mat into the flex pipe and push it up to the connection box.
Step 6 The mirror can now be mounted either directly in the tile adhesive or with acid free silicone after the tile adhesive has dried. Remember: the tile adhesive must be approved for mirror mounting.
Step 7 To improve the final look, mount the tiles next to the mirror in line with it.