CalculatorUnderstanding and working out your energy costs can be a complicated endeavour. For a truly accurate cost analysis, a whole slew of variables come into play such as the quality of your insulation, the location of your property, the power usage of your energy system and your supplier’s tariff rate. It’s easy to become lost in this labyrinthine maze of technical jargon while you conduct your research, but in most instances, the average person won’t need to go into this level of depth when making their calculations. If you want to know how to work out the running cost of your heating, we’ve made straightforward instructions that are simple to put into practise and could help you make a more informed purchase for your next appliance. 

The calculation we’re going to use will give you an estimated figure of the running cost for an electrical heating appliance. It won’t take into account any other conditions, such as room size, insulation or draughtiness, but it can still provide you with an average figure that can assist in comparing products. To begin with, you’ll need the wattage of the appliance you want to calculate. For the sake of our example, we’re going to assume that we’re calculating how much it will cost to run a 1000W electric radiator for 1 day.

1.      Convert Watts to kW

To calculate your running costs, you’ll need to convert the wattage of the appliance to kilowatts; this can be done simply by dividing your wattage by 1000. In our example, we’re dividing our 1000W radiator by 1000 to give us 1kW.

If we were using a 1800W radiator it would be 1800/1000 = 1.8kW, or if we were using a 450W radiator it would be 450/1000 = 0.45kW.

2.      Multiply by hours in use

Next you will need to multiply the kW figure with how many hours you estimate the heater will be in use each day. This is likely to be very different depending on the season, but let’s say that we’re planning to run our 1kW radiator for 6 hours a day because it’s winter and likely to be quite cold in the mornings and evenings. Multiplying our 1kW radiator by 6 will give us 6kWh (kilowatt hours) which is how much energy it’s expected to use in the day.

If we planned to use a 1.8kW radiator for 4.5 hours, we’d get 1.8 x 4.5 = 8.1kWh. Or if we wanted to use a 0.45kW radiator for 7 hours, we’d get 0.45 x 7 = 3.15kWh.

3.      Multiply by pence per kWhCoins

This is where it can really start to vary as the next step depends on the energy prices set by your provider. As of March 2016, Energy Saving Trust estimated the average price of electricity to be 13.86 pence per kWh so we will round this up to 14 pence for our example. This information is usually displayed on your energy bill so you can easily substitute your own provider’s rates into the equation. By multiplying the expected kWh figure with your supplier’s pence per kWh, you will find out how much it will cost to run your appliance. In our case, it would be 6kWh x 14 = 84p or £0.84.

The cost to run the 1.8kW radiator for 4.5 hours would be 8.1 x 14 = 113p or £1.13 and the cost to run the 0.45kW radiator for 7 hours would be 3.15 x 14 = 44p or £0.44.

4.      Multiply the number of days

As this gives you an estimated running cost for one day, you can then multiply this figure by 7 to give you an estimated cost for one week, by 30 for an average month, or by 365 for a yearly total. We’ve established that the 1000W/1kW radiator costs 84p to run for 6 hours a day on a 14 pence per kWh tariff. The calculations below give a weekly, monthly and yearly estimated cost for the appliance, assuming that it will be used for 6 hours every day.

84 x 7 ÷ 100 = £5.88 per week

84 x 30 ÷ 100 = £25.20 per month

84 x 365 ÷ 100 = £306.60 per year

5.      Create a more realistic figureCalculating Heating Costs

The predicted costs above might look higher than you would think but they reflect an unrealistic, worst-case scenario that assumes the appliance is operating at maximum output for the entire hour it’s in operation, which is absolutely not the case. Other electrical devices such as TV’s and computers will be using electricity continuously until they are turned off, but appliances like fridges or heaters have highly accurate thermostats which will switch them on and off depending on the ambient temperature of the room. In reality, the electric radiator we used in our example might only be using around a third of the energy estimated to occasionally maintain and boost its temperature levels.

Let’s say our radiator will only be drawing power for a third of the time, so we can divide these figures by 3.

(84 x 7 ÷ 100) ÷ 3 = £1.96 per week

(84 x 30 ÷ 100) ÷ 3 = £8.40 per month

(84 x 365 ÷ 100) ÷ 3 = £102.20 per year

These figures are a lot more representative for calculating the cost of a radiator, but keep in mind that your radiator may be drawing power more frequently if it’s trying to maintain the heat levels of open-plan or poorly insulated rooms.

What to Consider When Working Out Running Costs

Once you’ve sussed how to work out the running cost of your heating, you can use these figures as a basis of comparison between other electrical heating appliances in your home to get a rough idea of potential expenditure. However, it’s advisable to take these calculations with a pinch of salt for various reasons – namely that you have to make so many assumptions in the process. For example, we’ve assumed that we’re going to be running our heater for 6 hours a day for every day of the year. Such a regimented lifestyle is extremely uncommon! How long we run our heating largely depends on weather conditions and the changing of the seasons so you may want to make separate calculations for warmer months to get a costing figure that’s a little truer to life. It can be easier sticking to smaller timeframes such as days or weeks which are much simpler to compare side-by-side rather than generalising in months and years.

If you’re looking at potential running costs of appliances and finding that they’re quite high, your first port of call should be to look for an energy provider that’s offering a lower rate. It can make a huge difference: comparing against the figures from Step 4, if you were running the same 1kW radiator for 6 hours on a 12 pence per kWh tariff, it would cost 72p to run for one day or £263 for the year.

All of the electric heaters we stock at Electric Radiators Direct display their wattage so you can make your own potential cost projections if you so choose. Don’t get too hung up on calculating running costs though – if you choose an underpowered radiator for your home, you can end up spending even more on energy as your heater struggles to warm a room it’s not suited for. Use our handy radiator calculator to find the right wattage to suit your home. Compared to traditional central heating, electric radiators are low maintenance and can be fitted DIY, eliminating costly callouts and installation expenditures. When you consider how energy-efficient our electric radiators are and how little electricity they require to maintain their heat levels, you could be saving more money than you realise. 

Electric radiator calculator