We have a typical wired mains-powered doorbell (door chime) like this. It’s powered by a 16W transformer which, I just noticed, is always warm to the touch. Which means it’s drawing at least a few watts all the time. It seems wasteful for something that gets used a few seconds a day at most. Is there a more energy-efficient alternative that does not involve batteries? All the ones I could find were either battery-powered wireless systems or transformer-powered.
I forget where but I’ve seen a system that uses the same kind of transformer as a typical system but it’s wired to a motion detector equipped porch light. When something gets close enough to the door to trigger the light, the doorbell gets powered up at the same time. It could even be rigged to trigger the doorbell automatically if you like the idea of making doorbell ditching even easier.
In all honesty though. I really doubt that the actual cost of the electricity being used is that large especially when compared to the cost of replacing a reliably functioning system with a slightly more efficient one. If you’re already replacing it for other reasons, sure go for efficiency. Failing that, just make sure the numbers add up.
BTW, what’s wrong with an old fashioned mechanical door knocker. Very efficient and they almost never have to be rebooted.
You could replace the crappy transformer with a nice, efficient DC switcher, and save a few cents each year.
Just buying a newer, high-efficiency transformer would be the simplest solution, but I’m sure you could also replace the whole chime/transformer with something electronically switched or with motion sensors to reduce idle energy use.
Go back in time and install one of these. I imagine it would pay for itself in 50 years or so.
You can try replacing the existing transformer with a toroidal transformer, as they tend to be more efficient (all else being equal).
So is there a 16V toroidal transformer or switching AC power supply that is no larger than a standard transformer like this?
Judging from the temperature, I’d guess the transformer I have now is drawing at least 5 watts. That’s $5 a year, which is trivial, but if there’s a solution that would pay back in 10 years I’d rather do that.
I agree; if you’re really concerned about this, go back to a mechanical door knocker.
in general, though, this sort of [standby power](https://en.wikipedia.org/wiki/Standby power) load is an problem all over the house, such as your HDTV, cable box and other electronics. Collectively, they’re using a lot more power than the few watts used by the doorbell transformer. And have you already switched to LED bulbs, gotten a smart thermostat and upgraded the insulation in your home?
Depending on the size and layout of the house, hard to hear in the back or upstairs, though.
In this case, higher operating costs are the inevitable result of greater capability or convenience.
I think the goal of reducing wasted “parasitic” power is a worthy one. In this case, it’s probably hard to save enough energy to pay for the doorbell upgrade, but when I had a dusk-to-dawn light fail, I decided to design my own LED version, and I paid a great deal of attention to the amount of energy that the photocell circuit was consuming. I got the total parasitic power down to around a Watt, which is significantly better than off-the-shelf lights.
Every wall wart you plug in will have a similar vampire draw, they will all be pulling 1 to 5 watts no matter if they have a load or not. A high quality transformer will save around 40% but will probably cost you ~$60 to do so.
While it is wasteful it is less wasteful than a DC based system would be. AC switching the magnetic flux 60 times a second requires work and will always consume some energy on a device like this which must be powered all the time.
Remember that this ‘wasted’ energy is being transformed into heat. Since the heat is inside your house, for about 6 months of the year, it is reducing the workload on your furnace, and so isn’t completely ‘wasted’.
A mechanical door knocker is not very convenient because we have a glass storm door over the front door. A knocker mounted on the glass storm door probably won’t be audible from inside the house, and I can’t count on every visitor knowing to open the glass door and use the knocker.
Yes, I’ve replaced every bulb with LED, and our air conditioner is only turned on on the hottest summer days or cold winter nights. I have also measured the standby power of most devices using a Kill-a-Watt and replaced any that was cost-effective to replace. I’ve also looked at every part of the house with a thermal imaging camera to find devices with high quiescent power as well as look for places with insufficient insulation.
Or a mechanical doorbell.
Not for a dog :rolleyes:
We have a ‘wireless’ doorbell. The push button and the bell are both battery powered, no wires. The batteries last for years.
It’s 44 kW-h per year at 5 W. At least where I live, that could easily be $15. Tax-free, too :).
This used to be true when wall-wart power supplies were simple iron-core transformers and rectifiers. But these days, I think just about every electronic device that uses DC power is fed by a switched-mode power supply, which tend to have extremely low stand-by power consumption. Some time ago I measured the power consumption of my phone’s charger using a Kill-A-Watt meter while not actually charging my phone, and ISTR it was a tiny fraction of a watt. I may be remembering wrong, but I can tell you it’s definitely not warm to the touch when it’s not charging a phone. I’ll meaure again tonight and verify.
We have no (working) doorbell and no knocker. Our home is secluded to the point that we get very few visitors and the ones we do get are expected (relatives for xmas eve dinner and the like).
Also, we have three dogs. We always know we have a guest long before they exit their car. I suggest the OP toss the chimes and replace them with three dogs.