Zappers intentionally attract bugs with their UV light to kill them. So you will suffer the incessant swarming of bugs towards the zapper and them flying around the area. So if you want to put up a bug zapper outdoors, you should keep it away from where people usually hang out.  In a way, bug zappers are also beneficial in eliminating mosquitoes that can be potential disease carriers. However, it’s not a 100% guarantee since mosquitoes aren’t entirely attracted to the light emitted by zappers. They are more drawn to the heat rather than the light. Some zappers also tend to make annoying noises whenever a bug gets caught up in it. Also, the fact that they are not selective with the insects they eradicate is a disadvantage because, as mentioned before, the good kind of insects can also be drawn to them and get zapped. Some examples are bees, beetles, and moths.  You do not need a bug zapper to get rid of insects. You will only end up attracting a lot of them to your property. Your best option would be to have lights that are not attractive to insects, like LED bug lights.