This first home had an old electric hotwater system on an offpeak tariff. We rewired it on to the peak tariff and put on a simple timer to allow the hotwater system to heat the water anytime during the daylight hours.
Pros: very cheap to install a timer and uses the existing hotwater system Cons: on cloudy/wet days the solar PV may not be generating much so some of the energy to heat the hotwater will come from the grid on the peak tariff rather than from the Solar PV system. |
This second home had an old electric hotwater system on an offpeak tariff. We rewired it on to the peak tariff and put on a surplus power diverter which heats the water anytime during the daylight hours when the solar PV system has surplus power.
Pros: uses the existing hotwater system and only uses surplus solar PV generation to heat the water, even on most cloudy/wet days Cons: costs more than a simple timer |
This third home installed an efficient heatpump hotwater system which uses around 1/4 of the energy of the regular electric hotwater system to heat the same amount of hotwater. The inbuilt timer is used to ensure heating only during daylight hours.
Pros: uses much less energy to heat the hotwater leaving more solar generation for other future purposes like charging an electric car or putting it into a battery to use the energy at night. Cons: costs more than a simple timer or power diverter |