Off Peak Heat 19 - Guernsey's new electric heating tariff 

"Will there be enough electricity?" 

This is one of the most common questions asked as Guernsey homes move away from fossil fuels towards electric heating. The challenge is less about how much electricity people use, but when they use it. Energy costs are under constant scrutiny, meaning many islanders are also asking what can be done to help shape a more affordable future.

Kenrick Brooks, Head of Sales and Solutions at Guernsey Electricity said “Electric heating that demands power immediately to heat a property uses a huge amount of power at peak times. By rewarding customers who store or use heat during off-peak hours (when power is cheaper to supply), we can make better use of Guernsey’s existing network. While we continue to invest millions on the grid, reducing peak demand means we won't need to build as much extra capacity to meet the short bursts of peak demand. This helps keep costs, and ultimately customer bills, lower than they otherwise would be.”

Launching in November 2026, the new Off-Peak Heat 19 Tariff offers lower heating rates for 19 off-peak hours a day, with higher rates during the five busiest hours to better reflect the true cost of supplying electricity at that time.

“The real test for any electricity network isn't an average day,” said Jon Sexton, Head of Engineering and Design. “It's the stress placed on the system in the busiest few hours of the year. In Guernsey, that's usually on winter evenings when people arrive home. Electricity demand peaks between 4pm and 8pm, making this the most resource-intensive and expensive period to supply power. Around 400 homes switch to electric heating each year. If hundreds of additional homes all draw large amounts of power at the same ‘peak’ times, more must be spent upgrading the network to keep pace.”  

Customers on this new tariff will shift enough power to heat an entire home (around 5kW to 8kW) away from peak periods each day, helping reduce Guernsey's demand for costly fossil-fuel power generation.

To help facilitate some of the States of Guernsey’s long-term decarbonisation targets, including the Electricity Strategy, Off Peak Heat 19 is designed to work with electric heating systems that automatically make use of off-peak, lower-cost electricity and a two-rate tariff.

This means most standard electric flow boilers currently on the Superheat tariff should not switch to this new tariff. However, anyone due to replace an existing electric boiler could choose a compatible off-peak heating system and then move onto the new tariff.

Find out more about Off Peak Heating

CUSTOMER ADVICE

• Interested parties should ask whether their home is better suited to a 'wet' or 'dry' electric heating system.
• If their preferred ‘peak’ heating system (such as a standard electric flow boiler or an air source heat pump) cannot be accepted due to local network constraints, an ‘off-peak’ heating option may still be possible.
• Compare the full cost - including installation, running costs, tariff rates and standing charges.
• Off-peak systems store cheaper electricity for later, helping reduce demand at the busiest times and are more likely to be accepted on to the electricity network.