There are many reasons why a garage door opens by itself. Some of those reasons are preventable while others are not.
The most common causes of the phantom openings are as follows:
Power surges can cause garage doors to behave in mysterious ways, namely by opening themselves. These surges often occur during lightning storms.
Equipment that is nearby your home operating on the same frequency as your garage door opener can also cause the door to spontaneously open and close.
Accidental Activation of Remotes
If you keep your remote to your garage door in a drawer, your pocket, or a purse, it is possible to activate the opener accidentally. When remotes are activated in this manner, the garage door will open without you knowing why.
One in a Million
One of the most remote and virtually impossible reasons for a garage door to open without your help is an accidental roll over code that two garage door openers share at one time. This is rare because the security on the roll over codes is set to a standard that makes two devices activating by one code at the same time virtually impossible. There are more than 100 million combinations of roll over codes.
There is no ghost playing pranks on you by calling out “garage door open” when you aren’t looking. The most common sources of this phenomenon can be easily explained by accidental and electrical causes.