Direct acting electric heating vs storage heaters

Direct acting electric heating and storage heaters both turn electricity into heat at the point of use, and both convert one kWh of electricity into roughly one kWh of heat. The difference is timing. Direct acting heaters, such as panel convector heaters, electric radiators, fan heaters and electric underfloor heating, produce heat when they are switched on. Storage heaters charge overnight on cheaper off-peak electricity, store that heat in ceramic or clay blocks, and release it through the following day¹.

That timing decides the running cost. Electricity costs around four times as much as gas per kWh, so any resistance heater is an expensive way to heat a home compared with a gas boiler³. Storage heaters soften the blow only where an off-peak tariff is available: they are cheaper to operate than standard electric heaters in a home without a gas mains connection, but electricity is still much more expensive per kWh than gas⁴. Direct electric panel heaters and night storage heaters are at least three times less efficient than heat pumps, which makes them very expensive to run⁵.

For a household weighing the two, the practical split is usually a combination rather than a choice: storage heating in the main living areas and hall, and direct acting heating in bedrooms, kitchen and bathrooms¹. What follows sets out how each works, what it costs, how the tariffs and grid constraints bear on it, and where building rules now stand.

Direct acting or storage: what each one does

Direct acting heating is the simpler of the two. These are wall-hung units on the main electricity supply that convert electricity into heat using internal tubes or fluid, switched on when needed⁴. The category covers panel convector heaters, electric radiators, fan heaters and electric underfloor heating¹. Because there is no store, there is no planning: the room is warm while the heater runs and cools when it stops. Direct acting systems are arguably the cheapest and simplest heating system to install, since they need no pipes, radiators or wet central heating¹.

Storage heaters work on the opposite principle. They store thermal energy overnight by heating internal ceramic bricks, and that heat is used to warm the home during the day¹⁰. The heat is held inside a core, often made from heavy clay blocks, and released gradually into the room through vents². Older units have manual controls, where the higher the input setting, the more electricity the heater uses and the more heat it stores; more modern units use digital controls, with thermostats and fans releasing heat when the room temperature falls below the set level².

The two are not mutually exclusive, and the standard pattern in electrically heated homes is a mix. Storage heating, static or fan-assisted, provides the base load heat requirement in the main living areas and hall, while direct acting heating covers bedrooms, kitchen and bathrooms¹. That arrangement uses the cheap overnight window for the rooms occupied for long periods, and instant heat for rooms used briefly.

Efficiency: both fall well short of heat pumps

Resistance heating has a low efficiency compared with other forms of electric heating, and proportionally converts one kWh of electricity into one kWh of heat¹². That is not a defect in the appliance; it is the physics of the technology. It also means the two options sit at the same efficiency, and the choice between them is entirely about when the electricity is bought, not how much heat each unit of electricity yields.

Against a heat pump the gap is large. Heat pumps are around three times more efficient than direct electric heating, and typically over three times more efficient than the most efficient gas boilers or electric heaters⁵. Direct electric panel heaters and night storage heaters are at least three times less efficient than heat pumps, which makes them very expensive to run⁵. Heat pumps are much more efficient than traditional electric heating options, which makes them cheaper to run³.

There is a counterpoint worth stating precisely. Electric heaters are more efficient than gas boilers in the sense that all the electricity they use is turned into heat, and electric heating is more efficient than using a boiler³. The problem is not conversion losses but fuel price: the higher cost of electricity more than offsets that efficiency advantage⁶. A household on resistance heating therefore gets a system that wastes almost nothing at the point of use and still costs more to run than gas.

Storage heaters add one further condition. They are only an efficient form of heating if the home is not on the gas grid, because electricity is more expensive than gas¹⁴. Where a gas connection exists, the comparison is settled by fuel price rather than by the heater.

Running costs: why direct electric is expensive to run

Electric heaters tend to be more expensive to operate than storage heaters, and direct electric heating typically has high running costs because standard rate electricity is more expensive than gas or oil⁴. The scale of the gap is consistent across sources: electricity unit prices are up to four times more costly than gas, and electricity costs around four times as much as gas per kWh¹⁵.

The tariff a heater runs on matters as much as the heater itself. Direct acting systems used on a standard electric tariff can be more expensive to operate than a storage heater on an economy tariff¹. That is the whole commercial case for storage heating: it moves consumption into a cheaper window rather than reducing it.

Installation cost runs the other way. Direct acting systems are arguably the cheapest and simplest heating system to install¹, while electric storage heaters typically cost £900 to £1,400 per room⁶. High heat retention storage heaters are more expensive to buy but lower to run than traditional or integrated models⁷.

Battery storage changes the arithmetic for direct electric heating, but not favourably on its own. Regular electric heating with battery storage is around three times as expensive as a heat pump setup, because the battery needed would be three times as big¹⁸. For a household, the honest summary is that direct electric heating buys low installation cost and high running cost, and storage heating trades a higher purchase price for a cheaper overnight rate.

Storage heaters and off-peak tariffs: how the timing works

Storage heaters charge during off-peak hours when electricity is cheaper, usually overnight, and release the stored heat the following day². They are designed to work with Economy 7, a tariff where night-time electricity is much cheaper, typically about half the price, but day-time electricity is more expensive⁷. Economy 10 works on the same principle, and storage heaters use Economy 7 or Economy 10 tariffs for cheaper energy at night⁸.

The operating cycle has two phases: a charging phase and a heating phase². Because the heater relies on heat stored overnight, planning ahead is essential, and it does not produce heat instantly like a regular electric heater². Some specific models that use particular time of use tariffs may need to be on all the time².

Not every storage heater suits every tariff. Dynamic storage heaters do not work with Economy 7, and their running costs are still higher than night storage heaters for that reason⁹. The meters and tariffs designed around storage heating include Total Heat with Total Control, Economy 7 and Comfort Plus¹¹. Most electric showers heat up their own water, so the storage heater does not need to be switched on for a shower¹⁹.

For energy independence, this is the central trade-off. A storage heater household is not independent of the grid, but it is unusually exposed to the timing of grid prices, and it can shift a large share of its heating demand into the cheapest hours. That is a real form of control, and it depends entirely on staying on a tariff that rewards it.

Grid impact: the extra stress direct electric heating places on supply

Direct electric heating draws on the network at the moment of use, which is typically the moment of peak demand. Storage heating does the reverse, charging when demand on the grid is low. In the case of electrified heating, thermal stores can be advantageous for generating heat when demand on the grid is low and electricity prices are cheap, reducing operating cost¹².

The carbon picture is less favourable than the efficiency argument suggests. Electric heating has a carbon footprint around three times that of gas and twice that of oil-fired central heating, per unit of heat delivered²⁰. That figure reflects the electricity used, not the heater, and it is the reason direct electric heating sits awkwardly in low-carbon policy.

Network capacity is a separate constraint. Very few homes are limited by fuse rating in the implementation of electric storage heating, but a large portion is restricted in other ways²¹. Storage heaters also need a connection to the correct circuit in your home and are hard-wired to the circuit, so the wiring, not just the heater, is part of the decision¹¹.

The independence question here is blunt. Neither option frees a home from the grid, and both depend on a supplier and a tariff. Storage heating at least aligns demand with supply, which is why it survives in policy while direct electric resistance heating is being squeezed out of new installations.

Where each option fits: panel heaters, storage heaters and electric boilers

The fit depends on the room and the tariff. Storage heating suits the rooms occupied for long periods, and direct acting heating suits short, intermittent use. That is why the standard arrangement in existing electrically heated dwellings is storage heating in the main living areas and hall, and direct acting heating in bedrooms, kitchen and bathrooms¹.

Storage heaters themselves divide into types. Static or fan-assisted storage heating provides the base load heat requirement¹. High heat retention models are more expensive to buy but lower to run than traditional or integrated models⁷. Control type matters too: once set, digital electric storage heater controls are easier to run than manual controls, because they automatically store enough heat for a set routine, and sensors and smart controls store just the right amount of heat².

Electric boilers are a different proposition from either. Usually these systems include a large hot water tank to store the heat⁶. That distinguishes them from a combi boiler, which does not use a hot water cylinder because all the heat and hot water comes directly from the boiler itself²³. Heat pumps, for comparison, require a water storage cylinder to provide hot water, similar to older generations of gas boiler systems¹³. Heat-only boilers have two extra header tanks to store cold water, usually installed in the loft if there is one²³.

For a household, the practical questions are whether a gas connection exists, whether an off-peak tariff is available, and how each room is used. Where there is no gas mains, storage heaters are cheaper to operate than a standard electric heater⁴. Where there is gas, the fuel price gap of around four times per kWh is the dominant fact³.

Part L requirements for direct-acting electric heating

Building rules now treat direct electric resistance heating as a last resort rather than a default. Direct electric heating will not be accepted in the majority of cases under the guidance covering energy assessments²⁴. In Northern Ireland, direct electric resistance heating is described as unlikely to be viable due to primary energy, possibly viable for occasional small rooms or in extremely low energy demand dwellings with on-site renewables and battery storage²⁵.

The classification used in Scottish proposals draws a distinction that matters for storage heaters. Direct electric heating and hydrogen are listed as zero direct emissions, while modern electric storage heaters and heat networks are listed as zero direct emissions plus, meaning systems with features to improve efficiency²⁶. Modern, efficient electric storage heaters can perform the same role as heat pumps in the clean heating systems listed for Scotland, as can wet electric heating and other direct electric heating technologies²⁷.

There is also a route by which storage heaters count as renewable. Under ECO4, electric storage heaters and Electric Heating Systems are classed as renewable heating systems when installed in a home which has solar PV or receives solar PV as part of the same project²⁸. Electric storage heaters on an off-peak or Economy 7 tariff also qualify as efficient heating in the Northern Ireland decent homes standard³⁰.

The direction of travel is clear enough. Direct acting resistance heating is being closed out of new and renovated installations on primary energy grounds, while storage heating survives where it is efficient, controllable and paired with a cheap tariff or on-site generation. For a household, that means the choice is less about which heater is better and more about which one the rules and the tariff will still support.