This is one of those subjects that entire Facebook groups have been devoted to! If the light ticking sound of the heater is a deal breaker then you may just want to avoid these devices.
The simple reality is that the pump makes a clear but fairly quiet ticking sound, operating at a low cadence when the heat is on low and ticking rapidly when on high.
Often the noise of the fan can drown out the ticking but on quiet nights in remote environments you will certainly heat it working.
What to do?
– hang the pump by a cable tie thus reducing the sound resonating thru the chasing. This is my own preferred method. I don’t install pumps like this as it looks unprofessional but I find it is effective
– put the pump in a box. Some people have tried using dedicated boxes – but with limited success.
– put the pump in a box and wrap it in foam. This method is reportedly quite successful as the foam and plastic layers dull the sound.
Beyond this its just about how creative you want to be!
For some people the ticking noise will be insignificant while for others it will be a constant frustration. I can only suggest you respond based on how you feel. If it doesn’t annoy you then that’s a good thing!