Cable boxes and DVRs consume more power over time than a fridge, according to the Natural Resources Defense Council. The stat is something of a stretch when you look at the details, but does under-pin a more important point for manufacturers.

Despite some headlines, the NRDC fridge comparison doesn’t refer simply to a set-top box, but rather a combination of a “typical” receiver box and a separate DVR, both of which are HD compatible. It also means using a new fridge-freezer that has earned the ENERGY STAR rating. In these circumstances, the TV boxes use a combined 446 kWh per year, compared with 415 for the fridge.

So for those of you with an old fridge, low-energy TV equipment, or a cable service that has the receiver and DVR in a single unit, the fridge is still using more power.

Precise figures aside, the important point is that TV boxes use more power over the course of the year mainly because they are usually operating continuously. Roughly two-thirds of all energy consumed by boxes comes when the user isn’t watching TV and the box isn’t recording a show. That leads to the somewhat counter-intuitive conclusion that overall a DVR consumes more power than a TV screen. (The New York Times puts it even more powerfully: unused TV boxes across the country use more power than the entire state of Maryland.)

The main point the NRDC makes in response to these numbers is to highlight the fact that, as a generalization, US manufacturers produce set-top boxes in a way that means they consume the same, or almost as much, power when not in use. It contrasts this to some European manufacturers and TV service providers who ship boxes that by default switch into a low power-state when not in use, for example after a certain period without any remote control activity, issuing an on-screen warning before switching down.

The problem is that when the box comes back to full power, it can take a minute or more to become fully active and responsive, particularly if there are a lot of channels and a lot of information required for the electronic program guide. One manufacturer notes having such features available in its boxes but has been asked to disable them by US service providers.

And by way of full disclosure, although I have such features available on my DVR, I have them switched off simply because adding yet another audio-visual box to my collection was enough of a tough sell to my wife without having to convince her that waiting up to a minute to be able to watch TV after switching on was an acceptable compromise!