Or better exhaust fan. I mounted a dimmer on my exhaust fan so I can adjust how hard it runs and I can "adjust" the humidity between 30 and 75% just with the fan.
Now, natrually you want the exhaust to go on full as much as possible to get more air through the cabinet but when lights are out photosyntesis stops and you can turn it down so it just keeps the humidity under control.
So imho a bigger exhaust fan >> dehumidifier as it also gives you the advantage of more air and not only lower humidity.
This will natrually not work if the humidity where you live is high, you can't vent out humidity with "wet" air. :)
I see the difference when it rains or is foggy outside that humidity in my growtent goes up 5-10%. Check what the humidity is in the rest of your appartment a couple of days and if it is 0-30ish % then I would certainly go for the fan over the dehumidifier.
Puffzter