Log homes can have instant hot water heaters.  Mike wanted to have an extremely energy efficient system, so he used a tankless hot water heater, also called an 'on demand. hot water heater. 

Beside the tankless heater is a insulated holding tank, which holds water that has been warmed by the solar powered water heater.  Because the water is pre-warmed, the tankless heater does less work, and uses less energy.