Help me decide which technology to use

I’m a complete newbie in home automation and currently exploring which wireless technology to use. I’m interested in making my light switches wireless, so that I can toggle them through my mobile phone, but at the same time be able to use the existing buttons on the wall as an alternative. I did some research and saw that I can either install mini wireless relays behind the switches, or completely replace the switches with wireless (Z-wave or Zigbee) ones (mains-powered, not using batteries).

Now, one thing that is of great importance to me, is minimizing the amount of time that these devices are actively transmitting data, as I’m concerned about exposure to electromagnetic fields. Ideally, I would like transmissions to be made only when I try to toggle the status of a switch through my mobile phone, or when I press the button on the wall and the switch needs to report the new status back to Homey. I do realize, however, that there needs to be some periodic polling as well. So I tried to find a clear answer on how often the Z-Wave and Zigbee technologies are designed to transmit when all the devices are idle, but failed. I understand that there may be no simple answer to my question, but I was hoping that maybe someone could shed some light on this topic.

Thanks in advance.

Im not an expert in electromagnetic radiation field but at least some insights:

  • zwave is forom may perspective robust protocol enabling to communicate between devices even without controller (direct associations) and you can set also polling interval (mostly for battery devices) and if controller enables it for all devices as well. However it seems to be the most expensive way to go compared to zigbee and wifi devices.
  • from my experience, most comfortable way of light control is with “microswitches” behind the original switch. Nothing will change compared to original setup but smart functionality will be added. Nad you don’t have to change design of your switches. In this respect, again zigbee is offering more options (relays, dimmers, potential free relays, rgbw controllers) but there is also cheaper wifi alternative Im going to test in upcoming week (Shely) - you dont have to rely on central hub and can control them directly over the app, but still can use Homey for controlling.
  • when concerning about radiation, I think that these devices will have much less impact than wifi router or cell phone in your house. Transmiting power is pretty low and not so frequent.