The answer varies from household to household, of course, and depends on numerous other factors, so it’s impossible to set a standard figure that applies to all homes in the UK. It’s possible to make estimates based on your usage habits, but you need to be aware of some important details.

Why it’s difficult to calculate the running costs

It’s common to lump electric heaters with other electrical appliances in your home, but there are various factors at play. All electrical equipment use energy in different ways. The television, for example, uses energy continuously when it’s switched on and stops using electricity once it’s switched off. The case is not similar to electric heaters – they use internal thermostats that switch on and off at intervals to maintain the set temperature of the room.

So, a 450W electric heater and a 450W plasma TV will not use the same energy when they’re both turned on for a specific duration.

Factors affecting the running costs

Electric radiators are designed to heat different types of houses and room spaces, which is why it’s impossible to pin down exact costs. Every space in your house is different, with a set of variables and requirements that affect heating efficiency.

  • Energy tariff – this is the most important factor when it comes to calculating your potential energy costs. Your electricity provider will charge you both a standing charge (which doesn’t change no matter how much energy you use) and a unit rate. The unit rate is charged against the amount of electricity you use; the more you use the higher the cost. It is the unit rate that is critical to calculating the potential cost of electric heating and unit rates vary between suppliers and tariffs. So, first of all, find out your unit rate from your electricity bills and consider the following example:

If you have an electric radiator with a 2kW (2000 Watt) electric rating, and it was a particularly cold day, we would assume the radiator would be on 100% of an hour. This means that you would be charged up to 2kW per hour for powering this radiator.

2kW/h x your unit rate = maximum cost of electricity used in 1 hour

Although this may seem significantly higher than a gas alternative, bear in mind that gas costs are increasing as supplies decrease and piped central heating systems with boilers have much higher installation and maintenance costs.

Whatever the costs may be, the aim should always be to minimise the amount of time the radiator is on for by considering some of the other factors below.

  • Insulation in the home and room – Older households often incur more costs in heating when compared to newer builds of similar sizes. New buildings are designed to offer better insulation because current regulations demand homes to be energy efficient. This standard ensures electric heating systems run efficiently since the level of heat loss is reduced.
  • Room size – Even in neighbourhoods with similar house designs, no two homes can be exactly alike, and the same goes for each room in a house. The ceiling height is vital as you’ll need more energy to heat a room with an open plan.
  • Personal preferences – Individual comfort levels determine the heating costs. For example, if you prefer a high temperature of 25°C, your bill will be much higher than a household operating at 18°C. If you set your radiators to deliver low heat, you’ll pay a smaller bill. Other usage habits will also affect running costs; these include seasons, changes in weather, lifestyle habits and work patterns.
  • Exposure levels and property location – Your home is not an impenetrable castle guarding you against the elements. For example, a house built in the middle of other houses benefits from residual heat, but a fully detached house is exposed to the elements on all sides.

How to calculate the running costs

It’s possible to estimate the cost of running your electric radiator using a simple calculation method. Bear in mind that this formula does not take into consideration all possible variables, so it’s just a base approximation.

The formula is as follows:

(Radiator output (kW) x hours in use) x pence per kW hour = daily cost of radiator (p)

For example, if you use an electric radiator with an output of 900W for 10 hours every day, multiply 0.9kW by 10 to get a cost of 9kW/h. If the tariff is charged at 14p per kW/h, you then multiply 9 by 14 to get a daily running cost of 126p. However, this formula does not take into account the fact that the electric heater has a thermostat that switches on and off depending on the outside temperature.

On a final note, when making estimates of your daily heating costs, consider your lifestyle habits as well as the quality of insulation in your home. The estimates provide a better way to predict your running costs so that you can make a more informed home purchase and interior design decision.