New member here. I have read a lot on this forum, but still can't figure this out. Looks like the variable will be $550-$700 more. We have an older passive solar on our 1 story roof right near the pool. We pay up to .33 in summer and .23 in winter (ack) for PGE (we have a well pump too). I wouldn't mind going for it and buying a Pentair VF *IF* I thought if would last or had a 3 yr warentee at least. Such a gamble! Wish I knew the fail rate. If you look on Amazon there are loads of unhappy folks. Advice? Thanks!!!!