Wrapping an exterior door handle with aluminum foil is a low-cost way some people add a layer of awareness before they sleep or leave the house. The method is not a lock and it will not stop a determined burglar. It is a simple tamper-evidence marker and a small audible cue. Tightly wrap foil around the outside handle so that any attempt to turn or pull it will wrinkle, tear, or shift the surface. When you return or wake up, a disturbed wrap can be a visible sign that someone tried the door.
The foil also makes noise. Thin sheets crinkle when they are touched or squeezed. That sound can give you a few extra seconds of warning if someone is testing the handle while you are home. Combined with a quick look at a window, a porch camera, or a phone, it can help you decide whether to stay put, turn on lights, or call for help. The idea is reaction time, not heroics. For an extra low-tech alert inside the house, some people rest a lightweight object—such as an empty cup—on the interior handle. If the handle moves, the object falls and makes a noise. It works like a passive tripwire and complements the foil on the outside.
This hack only makes sense as a supplement. Solid locks, a door that fits the frame, outdoor lighting, and working cameras still do the real work. Foil will not replace any of those. It can, however, discourage casual testing of a door and give you a cheap record of whether the handle was disturbed while you were away. Use it on a door you actually use, check the wrap when you come home, and replace it if weather or regular use has already wrinkled it. A wrap that is already loose tells you nothing.
In short, the aluminum-foil handle method is an inexpensive way to detect tampering and add a little situational awareness. It is pitched for people who want a quick, low-cost extra layer without buying new hardware. Keep the primary security in place. Treat the foil as a marker and a noise-maker, not as protection. If the wrap is intact in the morning, you have one more small reason to feel that the door was left alone. If it is not, you have an early sign that someone tried it.