Start by thinking about the following:
- Integrating?
While a non-integrating noise level meter simply displays the current noise level in real time, an integrating device will also give you an average sound level value over a set period of time. So if you only need it for spot checks with fairly stable noise levels, go for the cheaper non-integrating technology. For most other occupational or environmental noise monitoring, an integrating unit is the right choice.
- Accuracy?