This is a simple model calculating the economics of a typical rooftop solar water heater, which can save around 1T of CO2 per household per year and lower water heating bills by 50-80%.
Economics are more challenging, due ti high upfront capital costs, which are quantified in the data-file.
Under our base case estimates, it would require a CO2 price of around $130/ton, to incentivize rooftop solar water based on global average insolation and gas prices.