It turns out AC and DC can be pretty close in lots of instances....especially if you count energy use as a cost in dollars and include the pumps purchase price. (This leaves aside heating, where you have to consider whether heaters are using up the power you've saved....if you're in a temperate/cool climate, chances are that you're not saving any power by using a lower-power return pump. Folks in the far-south can probably do a little better, but even then the economics of these Quiet One pumps can work out pretty well.
For example I think a DCP5000 would give improved flow over the Quiet One 2200 in this application, but...way more flow than is needed, the DC pump costs about double the price, and it uses about the same power.
Based on some experiences I've read about, it seems like flow ratings on at least some DC pumps may be optimistic – if so, that would make the comparison even closer.
The one pretty universal advantage DC pumps seem to have is head height....for them to claim 500 GPH at 9' on the DCP5000 is impressive, if true. At that height, you'd need a Quiet One 5000 @ 123 watts and that would give you a bit over 600 GPH. Price is similar between the DCP5000 and Quiet One 5000 though. For most folks with a sump under their tank, this extra height isn't an advantage though.
(BTW, these Quiet Ones are the Sicce Syncra Pro design, but made in china for Lifegard Aquatics.....same 3 year warranty as the old italian made models.)
