Well I happened to be on Dahua's site and hopped over to the analog section.
Their non-IR minidome has a max wattage rating of 2W.
The IR bullet has a max consumption of 4W.
Is there something in these calculations they're not sharing?
I assume the "standard DVR server" comment means they're dividing the number of cameras by the total power consumption of the DVR and adding the camera power to that.
I assume for the IP camera they're not including the power consumption of a recorder. Or maybe they're assuming that NVRs use less power than analog DVRs.
Camera vs camera: an M300x will use about 2.2-4.6 watts. Let's say a Pelco FD1 (similar form factor fixed dome, but analog) uses 1W (or at most 2.7W w/IR). The M300x is pretty good on power as far as IP cameras go. But if you're really comparing apples to apples with power efficient cameras the argument is definitely about the power consumption of DVRs vs NVRs.
Some DVRs I'm familiar with are on the order of twice as power hungry as a comparable PC that one might use for VMS software/recording. But I don't think that makes up the 7x number they're claiming.
We do argue that one particular solution we have saves money on power. A 30W recorder, 1.2W cameras and even with a 12W POE switch a 12 camera system is only 56 watts. But this is a deliberately low power recorder (for thermal managment reasons) and about as low as you can go in terms of power in an IP camera.
Point being, I don't think it's fair to assume all DVRs are expensive to run and all NVRs are really cheap. And both IP and analog cameras can be thrifty on power.
Another in a long line of dubious Axis claims. Remember the Axis study that claimed a 40-camera IP system had a lower TCO than a 40-camera analog system? That "study" was based on the questionable assumptions that a network was already in place, that IP cameras were only 50% more expensive than analog cameras, that the added cost of camera power cables tripled the cost of cabling and that installation, configuration and training for an analog system cost 50% more for the analog system.
I have to wonder why Axis continues to publish these blatantly biased "studies" when there are many less questionable points of comparison between the two technologies. It tends to make them look desparate.
I believe they are counting only the IP camera vs the Analog Camera + DVR. Obviously, if you don't have headend equipment, the IP camera is going to consume less power. But, this isn't apples and apples.