Is it cheaper to use an electric heater or central heating?

I am self-employed, work from home and spend most days alone in the house. I am trying to avoid putting the heating on during the day to save money, but really feel the cold at times.

Would it be cheaper to turn the heating on for a bit to warm up, or use a fan heater that we have?

We have a 2000W fan heater, with a thermostat and temperature control, that we used to use in the unheated laundry room, but stopped as running it all the time was costing a small fortune. It is quick and good at warming up a room, though.

I thought if I put this in the room with me then it could provide a cheaper alternative to putting the heating on, but I don’t know what the rough cost of running the central heating would be. Our home is a three bedroom, detached, not very well insulated 1960s house.

Angharad Carrick of This Is Money replies: The weather has turned cold and we’re all now reluctantly having to think about turning the heating on a bit more – or on at all for some of those who have been braving it out so far.

But with bills going up, even with the energy price guarantee, we need to consider the most efficient way to stay warm.

In a typical household, over half of the energy bill is spent on heating and hot water, according to the Energy Saving Trust.

Given your home is not well insulated you’ll be losing a lot of that heat if you turn on the heating for every single room, so you’re right to consider using a portable heater rather than central heating.

Fan heaters are a popular solution to keeping yourself warm if you’re in just one room, particularly if your home is not well-insulated. You can buy a basic one for as little as £14, so the outlay is fairly small. 

However, it is worth noting that spending a bit more will get you a much better and potentially more efficient heater, ideally with a timer and thermostat. 

Fan heaters give off short-term heat so you’ll be able to feel the benefit almost immediately, but once you switch it off the heat will disappear.

You should also consider how effective a fan heater will be if you have a big room or high ceilings. It will be harder to warm the room, and yourself, with a fan heater and it might have to stay on for longer to do so.

If you want to heat a room for an hour or two, then a fan heater is a good option. However if you’re working all day in the room and running it all day too, it will not be as cost-effective.

You say you don’t have a very well-insulated home, so if you do use a fan heater you will also want to maximise the warmth by finding ways to trap the heat in the room.

You’ll want to make sure your door is shut to retain the heat and you might want to consider a draught excluder. If you really want to retain as much heat as possible you could close the curtains, but this may not be ideal if you plan to work there all day.

You can work out much it costs to run your fan heater, and other appliances, with a quick calculation.

How much do fan heaters cost to run?

Every appliance has a power rating, usually given in watts (W) or kilowatts (kW) and 1000W equals 1kW. 

This tells you the amount of electricity it uses – and how much it costs you will depend on how long it’s turned on.

Electricity is sold by kWh, which tends to come up as ‘units’ in your bill.

You can work out how much an electrical appliance costs to run by multiplying the device’s wattage by the number of hours you use it and then by the cost of electricity.

Electricity is capped at 34p per kWh under the energy price guarantee that limits the energy price cap. If you are on an energy price cap standard variable tariff this means your 2000W or 2kW fan heater will cost 68p an hour to run. (2kW x 34p x 1 hour).

If you’If you just use it for an hour long blast, or even a shorter period of time, then you won’t run up too big bills. But if you are working a full day and running it for that, say 9 hours, that will cost £6.12 a day.

Whether this saves you money compared to using the central heating will depend on how efficient your boiler is. Boilers use gas, which is cheaper than electricity at 10p per kilowatt hour, but not all models cost the same to run. 

Boilers are measured in kW too and modern combination boilers tend to range from 24kW to 40kW. Combi boilers heat water on demand and so are more powerful than system boilers (those that work with a separate hot water tank) and these tend to range between 9kW and 40kW.

You can find out how powerful your boiler is by looking at the details on it, or by finding its model description and looking that up on line. 

With gas currently fixed at 10p/kWh, an average three to four-bedroom house’s 35kW combi boiler would cost £3.50 to run for an hour. 

With a less powerful 26kW system boiler for a similar size house, it would be £2.60 per hour.  

But these are just rough estimates and the actual cost depends on lots of different factors. However, you can see that an hour of the fan on in one room would definitely seem to be cheaper than an hour of the central heating on.

One of the key things to remember is that even if you put your heating on for an hour, if you have a thermostat set to a not too high setting then the boiler may not be running for an hour. So, for example, if your thermostat is set to 18 or 19 degrees, the boiler should run to keep the house at that temperature and once it has reached it, then it will not run constantly.

I’m not sure what kind of boiler you have, but a modern boiler is, unsurprisingly, more efficient than an older one. Their main advantage of the most efficient is that they are condensing which means they recover more heat.

One way to cut costs when using your central heating is to adjust the your boiler flow temperature.

Charity Nesta says households using combi boilers should set the ‘flow temperature’ lower to use energy more efficiently and save £112 a year, without compromising on the temperature of their home.

You might also want to consider switching off radiators in other rooms or getting thermostatic valves to cut some costs. 

> Read our guide on how and why you should consider changing your boiler flow temperature 

Is a fan heater cheaper than the central heating?

Joanna O’Loan, knowledge manager at Energy Saving Trust says: ‘There are several factors that will affect this, but if you have gas central heating, it is generally advisable to use this over individual electric heaters, if you’re looking to keep costs low.

‘Despite the recent price rises, gas is still roughly three times cheaper than electricity per unit. To use your central heating just for heating one room, we’d suggest using your radiator valves if you have them. Turn the radiator valve high in the room you’re in and low or off in the rooms you’re not using. 

‘Minimise heat losses to the unheated spaces by keeping doors closed and using draught excluders to block the gap between the door and floor.

‘However, if your boiler is old and inefficient, your room is especially large or you don’t have radiator valves, and your fan heater only needs to be on a few hours, then it may mean your boiler would use fewer units of energy than the electric fan would.

‘You’ll get less heat from the electric fan but may be cheaper to use the fan heater sparingly.’

Other ways to save money on your bill

We’re often told to turn off lights, use the tumble dryer sparingly and have quick showers which all contribute to keeping your energy bill down.

There are other things you might want to consider to keep warm in the winter months. A hot water bottle is a popular way to keep warm and it costs very little to fill.

An average 3000W kettle costs £1.02 per hour to run but it should only take a minute or two for each boil. It would cost less than 9p to boil your kettle for a total of five minutes per day, and your hot water bottle should keep you warm for a few hours.

> Read our guide on how much other appliances cost to run 

There are also a number of products like an electric blanket, a hooded blanket or other things you can buy. We recently tested items that warm the body, including  a wearable sleeping bag.

If you’re keen to cut costs further you should look at energy efficiency labels on your devices.

Understanding energy efficiency labels can help consumers make some serious savings in the long run, or stop them overspending on an ‘energy saving’ device that will never pay for itself.

Appliances are tested for how much energy they consume at a ‘typical’ level of use and are then rated on a scale of A to G, with A being the most efficient and G the least efficient.

The label should also tell you how much energy your device will use in kilowatt hours, but this will vary between appliances.

As the weather turns colder, older people are also being urged to apply for pension credit by 18 December in order to unlock £324 in cost of living support.