Carpenter bees are put off by wood that’s been chemically treated (which makes it more challenging to burrow into). Even a coat of clear varnish (not a wood stain, which does not have the same repelling effect) will deter them from drilling.
The strong smells of orange, lemon, lime, lemongrass, bergamot, and grapefruit are powerful enough to deter them, yet safe enough to use around your home as a natural bee repellent.
It isn’t the sound the chimes make that bothers and distracts bees, it’s the vibration. In a similar vein, you can even install outdoor speakers around potential problem areas (as long as you remember to turn them on often).
The bees emerge from their nests in August and September to feed on nectar and pollinate flowers before overwintering (often in abandoned nest tunnels). So your best bet for sealing any holes is in late September when most, if not all, the bees have left the nests.
Every spring they have the huge task of drilling holes and building nests, so if they can find anything to make their jobs easier, they’ll likely take it. That’s when a solitary bee house like the ones below can be an effective remedy for keeping carpenter bees away from your own house.