Storage heater
Alternatively, solar storage heaters are designed to store solar energy as heat, to be released during the night or other periods where it is required, often making it more cost effective than selling surplus electricity to the grid and buying it back at night.
[1] Storage heaters are typically composed of clay bricks or other ceramic material (grog), of concrete walls, or of water containers.
All high heat retention storage heaters are also Lot 20[3] compliant, in line with the EcoDesign regulations which came into force on 1 January 2018.
It states that all installed electric heating products manufactured from 1 January 2018 must have an electronic thermostat with a 24-hour, 7-day timer with either adaptive start or an open window sensor.
[4] Optional additional compliance features are distance control, adaptive start and open window detection.
Most storage heater users follow simpler guidelines; for example, in the middle of winter, it is often appropriate to turn the input switch to its maximum setting.
There is no need to touch the input switch on a daily basis if the same sort of weather prevails for weeks at a time.
In this case, if the manual output switch is not set to minimum overnight, the damper will automatically close (as if the output switch had been set to minimum), and then the damper will re-open after a time delay; this time delay is measured by the gradual drop in the heater's core temperature, and is therefore longer if the core temperature started higher due to more charge.
Some thermostatic heaters also make use of on-peak electricity when there is not enough stored heat to maintain the requested temperature; the user may wish to be aware of this and lower the settings.
In common with other forms of direct electric heating, storage heaters are not necessarily environmentally friendly because the source of electricity may be generated using fossil fuels, with up to two-thirds of energy in the fuel lost at the power station and in transmission losses.
[10] In Sweden the use of direct electric heating has been restricted since the 1980s for this reason, and there are plans to phase it out entirely—see Oil phase-out in Sweden—while Denmark and Germany have banned the installation of electric space heating in new buildings for similar reasons (though in Germany the ban was lifted in 2013).
In some countries, the current design of the electrical generating system may result in a surplus of electricity from base load power stations during off-peak periods, and storage heaters may then be able to make use of this surplus to increase the net efficiency of the system as a whole.
However, future changes in supply and demand—for example as a result of energy conservation measures or a more responsive generating system—may then reverse this situation, with storage heaters preventing a reduction in the national base load.
Compared to other forms of electric heating, storage heaters are cheaper to run[12] and they impose lower peak loads.
[10] Air source heat pumps give similar efficiency increases and are generally easier and cheaper to install for domestic use.
These are not to be confused with air conditioning (A/C) heat pumps which provide cooling with an increased carbon footprint and are now considered to be an environmental liability in some, (in particular hotter climate), countries.
