Smart water heating
Heating hot water accounts for about 15% to 20% of a typical UK household’s energy bill. By using smart controls, you can ensure your water is only heated when needed, or even better, heat it using “free” energy from your solar panels or cheap overnight electricity.
Solar Diverters (Immersion Controllers)
If you have solar panels, a solar diverter (like the myenergi eddi or Solar iBoost) is one of the most effective upgrades you can make.
- Monitoring: The diverter monitors how much solar power you are exporting to the grid.
- Diversion: Instead of letting that power leave your home, it “diverts” it to your hot water tank’s immersion heater.
- Savings: This effectively turns your hot water tank into a thermal battery, storing your excess solar energy as heat for use later in the evening.
Smart Hot Water Controls
Traditional hot water timers are “dumb”—they turn the heating on regardless of whether the tank is already full of hot water. Smart controls offer much more precision:
1. Temperature sensing
Smart sensors (like the Tado or Nest hot water kits) monitor the actual temperature of the water in your tank. They only turn the boiler or heat pump on if the temperature drops below your set point.
2. Remote management
Use your smartphone to boost the hot water if you have guests staying or turn it off entirely if you are away on holiday.
3. Legionella protection
Most smart systems include an automated “anti-legionella” cycle, which periodically heats the water to 60°C to ensure it remains safe and bacteria-free, even if you are keeping it at lower temperatures most of the time to save energy.
Integration with Time-of-Use Tariffs
If you don’t have solar panels, you can still save money by using a smart tariff.
- Load shifting: Set your smart hot water controller to heat the tank during the cheapest 4-hour window overnight (e.g. 2am to 6am).
- Thermal storage: A well-insulated cylinder will keep that water hot for the entire day, meaning you never have to pay peak-rate prices for your showers.
Cylinder Insulation: No matter how smart your controls are, they won’t be effective if your hot water tank is losing heat. Ensure your cylinder has a high-quality factory-fitted foam jacket or a thick retrofitted “lagging jacket.”
Key hardware
- Smart Cylinder Stat: Replaces the old dial on the side of your tank.
- Internet Gateway: Connects your hot water system to your home Wi-Fi.
- Three-port Valve: Allows your smart system to control heating and hot water independently.
Learn more about other smart controls and how they can help you manage your home’s energy.