The IR543 does not make any noise at all. The wall switches are dimmers and will emit a slight hum at the swtich when in use. This is not a loud hum and it is common with dimmer switches. This switch is rated at 600 watts. If you need more wattage, there is also a 1000 watt version available. You might also consider a similar switch made by PCS. It has the same features, and a few additional ones. One nice feature is the ability to program the "ramp" timing when the light is turned on/off. The Leviton switch is timed at 2 seconds. The PCS switch can be programmed from instant to 13 minutes. You could simulate sunrise! The price is about the same. We carry both of these switches. For current pricing send us an e-mail.
Every dealer in the country is out of stock on the IR543 (including us). There isn't a firm date on when X-10 (the manufacturer) will have this product available. It was estimated that the product would be available last week, but now there is no ETA given. I will post a message to this forum when we get them in stock.
If you wanted to begin using X-10 switches and modules now you still can do it by purchasing an RF remote and transceiver. The RF remote is very nice looking (I can e-mail you a picture if you would like to see it), and it will allow you to control up to 16 X-10 devices (like the IR543) from anywhere in your house. It has a nice pop off window where labels can be placed. We offer the RF transceiver with a 16 channel remote for under $40. You can add as many remotes as you like for different rooms.
RCI Automation[Link: ourworld.compuserve.com]