i reckon - you should think again about using pv energy to heat hot water - basically you are increasing CO2 emissions becuase you are displacing gas (low CO2 emissions, what you would have heated the water with otherwise) with electricity (high CO2 emissions).if you didnt use the iboost, someone up the road would be utilising your free low carbon electricity. as it is, they are now burning high grade electricity instead - pv water heating makes sense financially, but not in energy terms. Sorry to be a party poop, but i find the detail important : )