Electric storage heating

Description
Electric storage heaters with automatic controls, using dual tariff electricity supply and hot water from an insulated tank with a dual immersion heater. Conventional storage heaters are charged with heat overnight on low tariff electricity such as economy 7. More modern versions have a much lower thermal capacity and are intended to hold a relatively small heat charge which is topped up during the day on other low tariff electricity.

Unit cost of installation
Around £2000. Replacement of a single storage radiator would cost £300.

Bulk cost of installation
Data not available

Indicative energy cost and carbon emissions

Maintenance
None normally required.

Technical suitability
Storage heaters are used with non-standard tariffs which require a separate wiring circuit and meter to be installed.

Conventional (high thermal capacity) heaters are relatively un-responsive and can lead to overheating in summer if the charge of heat is not required. The more modern (low thermal capacity) types are more responsive to the actual temperature conditions and thus may be slightly more efficient, although running costs will depend heavily on the particular tariff being used.

Systems should be properly sized for expected heat loss of dwelling. This is particularly true of high thermal capacity types if adequate heat is to be provided for the whole of the demand period. This may be difficult to achieve in dwellings with a very high heat loss, so it is important to insulate larger properties well.

Non-technical constraints
If the system is under-sized occupants may use more expensive on-peak electric or other heating to make up for shortfall.

Potential concerns with fuel poor
No specific issues

Ancillary benefits
Electric Storage heating would be an option where gas would be unsuitable (e.g. in tower blocks / flats).

Improved heating (coupled with insulation and ventilation measures) will reduce incidence of condensation and mould growth, thus decreasing maintenance costs for the building fabric and reducing damage (resulting from mould growth) to occupants¿ possessions. There may also be benefits to occupants health.

Trigger points for work
When rewiring work is undertaken, although dedicated circuitry is required.

Performance Limitations
Unlike controls for wet central heating systems which react to prevailing conditions, controls for high thermal capacity storage heaters need to anticipate the weather conditions on the next day in order to store an appropriate 'charge' of energy ready for use. Weather sensing controls are available (either built in to heaters or stand-alone to control a number of heaters), and 'weather prediction control' is available whereby the electricity supplier controls the charging period to suit the weather forecast, in conjunction with a special tariff.

Technical Guidance Available
» GPG 345 'Domestic heating by electricity'