We recommend that the immersion heater is used during summer months and the thermostat timer for the ZEB to recharge the cylinder is turned off. To minimise cost ensure the immersion heater operational times are in line with the cheapest energy periods on your tariff.
If your hot water heat demand is higher than that the immersion heater can provide, please enable the hot water thermostat timer to charge the cylinder just after the longest ZEB charging window. For example if you have a 4 hour window between 00.00 and 04.00 set your cylinder to recharge from the ZEB at 04.30. This ensures that the heat going into your ZEB is transferred to the hot water cylinder and not lost to heating your home through the ZEBs small standing losses.