Originally Posted by slownsteady
Why should it circulate at all? I thought the savings were achieved by instantly heating the water when needed. When you do your calculations on savings, you have to take the power to recirc into account.
Those little pumps, similar to the small Grunfos pumps, are so small, that there was no noticeable increase in power consumption. I have both of my bathrooms about 70' away, so without initial circulation, those 1/2" copper lines must first get warm and eliminate the cold water before achieving the warm water, unless the pump was first activated where the water would come out instant hot.