I'm wondering too. I actually tested almost all devices at home and the idle power consumption actually quite different from my previous perception. The following are a few I tested: 1. Microwave Oven. ~3W. 2. DECT phone base. ~2W. Extension unit. ~1W. 3. IP phone. ~1W. 4. Cable Modem. ~10W. 5. Routers. ~3W to 20W. 6. Switches. ~1W to 30W. 7. NAS(4Bay). ~40W. 8. Raspberry Pi 3B. ~3W. 9. Chargers/Power adapters. ~0W to3W. 10. WIFI Smart Plugs. ~1W when switch off. ~1.5W when turned out, both no load at all. 11. Set top box. ~15W, on or off. 12. PCs/Laptops. ~3W off, ~5W to 15W on.

To me the DECT phone, Set top box, cable modem consumes much more than I thought. Routers/Switches are more or less align with what I thought. What surprised me was that chargers/power adapters from decent brands were doing much better than I expected. Most chargers/power adapters I have consumes ~0.1W when idle, some event shown as 0w. Except one dodgy one came with a cheap toy PC behaves pretty weirdly: peaks at around 10w when just plugged in then gradually reduced to ~1.5w. Might be because it is a traditional power supplier with a transformer in it.

So the standby power consumption of my household should be just below 100W and I don't see how I can get it close to 500W.