Hot Water From Solar PV Panels
A solar-diverter can send suitable surplus electricity to an immersion heater instead of exporting it immediately. It can be valuable—but only where the cylinder, immersion and control arrangement are suitable.
The controller follows export and adjusts the immersion load.
A compatible diverter monitors electricity flow at the grid connection. When surplus solar would otherwise be exported, it proportionally supplies the immersion heater, subject to system limits and the cylinder thermostat.
Use genuine surplus
The control should avoid importing expensive electricity merely to heat water unless a scheduled boost has been chosen.
Keep safety controls
Cylinder thermostats, over-temperature cut-outs, immersion ratings and protective devices remain essential.
Set priorities
Where a battery is installed, the homeowner should understand whether surplus fills the battery or heats water first.
Compare export value
Diverted electricity gives up its export payment. The value depends on the alternative water-heating fuel and the current export tariff.
Check the plumbing and electrical arrangement first.
- Hot-water cylinder and immersion heater present
- Immersion element condition and rating
- Dedicated circuit and protection
- Meter sensor location and direction
- Battery and EV-charger priorities
- Space-heating system and hot-water schedule
Solar hot-water FAQ
Will it heat a full cylinder every day?
Not necessarily. Available surplus changes with season, weather, household demand and array size.
Should the battery or immersion come first?
It depends on energy prices, hot-water fuel, export rate and household routine. Compatible systems can be configured around the preferred priority.
Can it work with a heat pump?
Sometimes, but control integration is different. A resistive immersion diverter should not be assumed to control a heat pump correctly.
Start with a proper solar assessment.
Tell Mr Solar about your property, electricity use and future plans. We will recommend a system around the building and the way you actually use energy.