I already ordered RPi5 8GB to upgrade my 24/7 running RPi4 4GB with DietPi 
I hope that idle power consumption will be better than RPi4.
Here: Raspberry Pi 5 Review: A New Standard for Makers (Updated) | Tom's Hardware
“At idle, without any added cooling, it sits at around 50.5 degrees Celsius and consumes around 2.7 Watts.”
But Jeff mentioned in his video that RPi 5 has lower idle power consumption that RPi 4:
see
blog: Answering some questions about the Raspberry Pi 5 | Jeff Geerling
running Debian GNU/Linux 12 (bookworm)
aarch64with kernel 6.1.32-v8+ (source)
here are good thread with interesting data, logs, thoughts Raspberry Pi 5 model B · Issue #21 · geerlingguy/sbc-reviews · GitHub