When the system first turns on we use your existing heat source i.e. combi boiler that will heat the cylinder to a pre-set temperature. With the Smart Tank-In-Tank cylinder heating the cylinder with your existing heat source is extremely fast. Once the hot water reaches it target temperature your existing heating source turns off and the Bunsen Air system takes over sustaining the temperature throughout the day or night at a much lower running cost.
The Bunsen Air Hybrid systems are a very low energy heating system, so you run your heating at a lower temperature than when using fossil fuel heating. If you do need that extra boost, then your existing boiler will kick in to help out.