Thanks for the comment. I respectfully disagree with your thoughts on an iBoost. When it is used, it means I'm not burning gas - that leads to a modest reduction in my CO2 emissions. Based on the data I've collected we've pumped ~0.96MWh into the iBoost - less than a quarter of what we've generated. Given our house's usage, we're still feeding back the majority of our generation to the grid.
If we had a boiler which instantly produced hot water when needed, an iBoost would be unnecessary. Given the limitations of our house - and my fondness for hot showers - I think it makes sense with our energy usage.