Hacker News Reader

Comment by fguerraz | Hacker News Reader

Also, even if your devices on standby draw the equivalent of £30 of energy per year, and even if you turned them off completely, you would still not save £30 a year if you live in a country where you need heating in the winter.

Because apart from light escaping by your windows, almost all that energy is turned into heat, and if it wasn't there, you'd have to heat up your home more.

View on HN

You are right, but your heating system is probably cheaper (unless you have simple electric radiators).

If you have a heat pump, it will generate about 3W of heat from 1W of electricity, so it's 3 times more expensive to heat with standby devices that with your heat pump.

If you heat with gas, it's much cheaper per kWh than electricity, but I'm not sure what the ratio is.

Exactly! Some people look at me with disgust for running an inefficient old AMD PC as my home file/print/backup server, but it's made the coldest room in my house very comfortable during the winter months. There are no central heating vents in this room so I would be using electric heat regardless, it just so happens that my heater is also filling an important technical role as well.

IIRC, a kWh of electricity is about 3x more expensive than a gas kWh. You’re correct if your heating is electric (resistive) though.

And if you use air-conditioning for cooling?

Then I guess you don't care about neither the environment nor money, so it's kind of a moot point.

(I am not talking about using it in reverse / heat-pump ONLY)

Yep, Your device heat adds to the load on your AC. So if you going to bother with unplugging devices, it is more beneficial on those hot summer days.

Perhaps related or not, I was wondering about the energy loss of AC/DC converters that are often used to power the device. This clearly happens when the device is switched on - the converter is a bit warm - but maybe it also happens when it is off ?

Reply on news.ycombinator.com