There are a couple of “always on” devices, that cannot be detected and that I cannot measure easily, for example I have a lighted doorbell hooked up to a transformer that is hardwired to the wall. (all from ~1957)
We all know about vampire loads, and I am sure this is drawing a few continuous watts (the transformer is even slightly warm to the touch). While I am not really worried about it, I am curious if anyone actually measured one of these.
Hi @altenbach - for what it’s worth, I would’ve guessed under < 5W based on similar types of devices I’ve seen reported.
I looked around a little bit and found this, for what it’s worth:
"The Kill-A-Watt did its thing and in a few seconds, I was shocked (not electrically 
to learn that my doorbell transformer and button lights draw a total of three watts of power. That’s 3 watts 24 hours a day, 365 days a year.
One year is 8,760 hours. 3 watts x 8,760 hours / 1,000 = 26.28 kilowatt-hours to run my doorbell. At my electricity rates that’s about $3.15."
Thanks for the link, that was about my wild guess (It’s hard-wired and not easy for me to measure). Of course this has been running for 63+ years so quite a dollar amount.
(Technology has definitely improved. I recently got a new FIOS ONT, and it is ~5x more efficient than the 12 year old previous model (~3W vs. ~15W). How times have changed. Some might remember 20 years ago where every “wall wart” power supply (router, switch, charger etc.) used about 2W with nothing connected. )
FWIW, this is about as much electricity as thermostats use. When I replaced my old round mercury thermostat with a modern Honeywell, I obviously needed to run electricity for it. I looked up the specs and found that a 5v transformer was what was needed. I found that Home Depot sells doorbell transformers in different voltages, but also a multi-volt transformer. I bought and installed that and voila. I have three thermostats though, so that’s be 15 watts (5v at 1amp) on 24/7.
As a follow-up to all this, the doorbell transformer was located in the furnace closet which we now ripped out and turned into a storage closet.
We decided to remove the entire old doorbell system and replace it with a wireless system (this one, but there are other similar ones). One receiver is in the detached garage, so we can hear the doorbell even there (a problem with the old system!). According to my kill-a-watt, the receivers use undetectable amounts of electricity. The doorbell itself has no batteries! The act of pressing the button generates enough electricity to trigger the ringers. Isn’t it nice to have visitors generate some of the electricity. 