Well, not really, because having a broken subwoofer actually saved electricity and replacing it will raise the consumption again. 
(… but wait, there’s more!)
Luckily, a local Costco still had a Klipsch R-12SW and I picked one up yesterday (Last day at $60off sale!). Sounds great so far, now I just need to find out why it does not go to standby when the receiver is off (The manual says that should happen after 15-20 minutes). Could my receiver still put out a spurious signal on LFE even if asleep? I guess I should hook it up to my solution for the old one.
Overall, the new subwoofer is significantly more power efficient while sounding great. The old one used 9W in standby and about 16W during use (see above link. Both fully calibrated with the setup mic of the receiver and at the same volume setting.) The new one uses only 5.5 - 6 W in typical use (I got it up to 10W by really cranking up the volume).
I am always amazed by the marketing. So the box of the new subwoofer says 400W amp. Apparently I am using way less than 2% of it! I don’t want to shatter my windows!!!