SolSafe is a plug-in, zero-carbon, green, smart, efficient-energy storage boiler that can directly replace existing fossil-fuel boilers or supplement heat-pump systems. It is a smart 75kWh thermal battery which connects to the electrical grid or can be charged from any 230V AC renewable source. It directly links into an existing radiator system and gives variable temperature output on demand. With a four-hour charging cycle, the system takes advantage of cost-effective time-of-use tariffs by design, which reduces consumers’ electric heating bills by up to 75% at today’s prices and helps to reduce fuel poverty.