Thermal Stores

What is a Thermal Store?

Thermal Store

In simple terms it is the reverse of a hot water cylinder. It keeps a store of hot water which it uses to heat mains water for domestic use. This means you have hot water at mains water pressure WITHOUT having to use booster pumps (like you do with a power shower)

It doesn't require a large cistern in the loft, so it can release space for other uses and allow the roof to be better insulated.

They provide mains pressure hot water without the annual maintenance issues associated with pressurised cylinders, and a greatly increased operating temperature range. They are suitable for gas, oil or electrical installations as well as those using renewable energies such as solar or heat pump. Thermal stores work well with under floor and other low temperature space heating systems.

Thermal stores are safe, open vented, highly insulated and efficient. They do not require expensive safety valves and are designed to upgrade existing traditional hot water systems to provide mains pressure hot water.

Thermal Store
A typical microgeneration  thermal store installation will:

  • Provide mains pressure hot water giving 'power shower' performance
  • Deliver up to 25 litres per minute filling a standard bath in 3-4 minutes
  • Provide a dry roof space eliminating the risk of freezing pipes/tanks in winter
  • Increase system efficiency and reducing running costs
  • Require little or no annual maintenance
  • Be simple and low cost to install


BS6700:1997 states that in un-vented cylinders, the maintenance and periodic easing of temperature relief valves is particularly important. This is a landlord's responsibility in tenanted properties and annual checks must be carried out by CITB trained persons or installers having G3 approval. As our stores are vented and therefore inherently safe, they are not subject to Building Control Regulations thus simplifying system maintenance enormously for landlords and homeowners.

It is not widely appreciated that uncased foam insulated cylinders can lose up to 40% of their insulation value within weeks of manufacture and can emit dangerous smoke if involved in a fire. The thermal stores we supply use safe, non-toxic, non-combustible Rockwool for continuous high performance during the life of the unit. There is no release of ozone depleting substances or harmful emissions.

Manufactured from copper sheet to BSEN 1653:1998, the thermal stores have computer designed heat exchangers produced from finned tube and incorporating a patented expansion chamber which is sealed for life. The units are tested hydraulically and pneumatically, both during and after manufacture.

Thermal Store