I finally pulled the trigger on the Geospring to replace heating my hot water with my horribly inefficient oil boiler. As I wasn't replacing an existing electric heater, installation was a little more involved, but pretty smooth. I did have an issue with the system thinking it wasn't filled with water, but that seemed to sort itself out. Took my first shower that didn't vary widely in temperature, along with no bouts of lukewarm water. Unusually for me I took out the extended warranty for $80 - it takes on site maintenance through to 12 years - I figured it was worth it as these types of units have been known to have issues with motors/circuit boards.. Pleased so far.