Scott,

Some of the X10 Appliance Modules do make a loud click (although the Lamp Modules are usually silent). I buy mine (for Australia) from [Link: x10-hk.com] as these are much quieter - good Chinese technology. I don't know for sure about the Insteon ones - Insteon doesn't work in Australia - but I think they are nearly silent. I'm sure that any place you want to buy them from will tell you if you ask. But remember that you cannot control Insteon devices using the IR543.