2. Consider hiring a local HVAC company to install an alarm for detection of tampering, refrigerant loss or voltage interruption. Some systems have a siren or some other audible alarm to alert homeowners when someone has compromised the system. You can have an alarm system installed on any existing or new air conditioning system.
3. Clear away any plants or fencing that hides the outdoor unit from view. If the area around the unit is overgrown, thieves can easily hide while they are tampering with it.
4. Improve lighting or install a new system near the air conditioner. Thieves will not try to steal anything after dark if the area has sufficient lighting to make them visible.
5. Microdots store information and can be brushed or sprayed on the copper tubing. The information they store is unique to your property and is visible with a magnifying glass.
6. If microdots are too expensive, engrave the unit and its components with your home address.