Caldera has developed a Zero Carbon Boiler (ZCB) which takes renewable electricity from the grid and converts it into heat which is stored within the unit until the consumer wants heating or hot water. The ZCB has an innovative core inside that is trademarked as "Warmstone" Technology. The Warmstone technology is a low cost storage media that is able to absorb renewable electricity and store the equivalent energy for a four bedroom home to cover a 24 hour period on the coldest winter day or seven days of hot water in the summer. The energy is retained with 5-10% losses per day with an efficient insulation strategy. These thermal losses are over 5x lower than conventional methods of storing heat, such as night storage heaters.

This project is about unlocking the full potential of the ZCB for Heat as a Service (HaaS) by:

1. Developing the communications so that the timing and rate of electrical charging can be set and varied on a minute by minute basis by an energy supply company,
2. Collecting heat usage data from the Heat Interface Unit (which replaces the conventional boiler), so that the homeowner can be charged just for the heat that they use rather than the electricity supplied to the ZCB
3. Working with large social housing landlords to establish initial trial sites, which will lead to 5+ installations in 2021 and can be used to demonstrate that rapid wide scale deployment is possible.

Supply side companies are currently developing software to actively control demand in the home and smarter ways to use energy by changing consumer behaviour. The Caldera Warmstone approach provides a means for storing electricity for heating. Heating is the largest home energy demand - normally 4x the rest of the homeowner's electricity usage.

The HaaS model will help low income individuals and families who will benefit the most from reduced energy costs by showing that a ZCB can be supplied and installed under a long term finance model.

The HaaS model has been trialed in a number of countries with heat pumps or conventional boilers, but not with a ZCB that is able to decouple electrical charging and heat supply by 1 to 7 days depending upon the time of year. This means that the unit can be charged when renewables are generating and the electricity price is lowest. Heat pumps work in real time and although they generate "additional free heat" they also have to operate when the consumer wants the heat or hot water, not when renewables are generating.

Low or zero carbon heating systems with lower cost of ownership normally have high upfront capital costs that make them inaccessible to those that have the most need for savings. To eliminate this initial capital outlay, the unit can be financed by a third party and the cost to the user spread over the expected 20 year life.