Are electric heaters eco friendly?

Portable electric heaters don't keep the whole house warm like central heating systems do, but they do provide you with a heating boost exactly when and where you need it. 

But are they eco friendly? And will you run up needlessly high bills? This comes down to whether you've bought a good heater that suits your needs and how you use it. Read on to find out more. 

Check out our reviews of the best electric heaters to find a top-quality heater for the cold months. 

Are electric heaters sustainable?

The conversion of electricity into heat doesn't produce harmful by-products, such as carbon emissions at the point of use. This is why you sometimes hear electricity being described as 'clean'.

But while the electricity you draw from a power outlet can be generated using renewable energy sources, electricity generation can still put a lot of CO2 into the atmosphere. 

It depends where you live, but the electricity you use in your home is generated from a variety of sources, including renewables (around 41%, on average), gas (38%) and nuclear (21%). You can't guarantee that you're using renewable power when you switch on your heater because electricity from all sources is mixed-up in the grid. 

Find out more by reading: What is renewable energy and differences between green energy suppliers.

How to use an electric heater frugally

• Set your heater's thermostat to a setting that works for you - it doesn't always have to be on full blast. This will mean that the heater will reach a stable temperature and only generate what's needed to maintain it.
• Use it in conjunction with central heating if you can find the right mix. It can be wise to keep your home heated at a baseline level and use an electric heater to provide warmth during the coldest hours and only in the room you're in.
• Use the controls that are built into heaters. Your heater might go up to 2kW or 3kW (more on this below), but that doesn’t mean you always need it at that level of heat output. Instead of blasting heat out on max all the time, toggle it to a low setting, such as 1kW or 1.5kW, then crank it up when you need to. 
• Consider how insulated your space is. You don't want a convector heater warming up your garden because the air is leaking from your home: this will leave you cold and out of pocket. Take a look at our guides to insulating your home.

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How much do electric heaters cost to run?

Most electric heaters have a maximum rated output – usually 2,000 watts (2kW) or 3,000 watts (3kW). Most heaters also have settings where you can adjust heat output – the more choices, the more control you have over getting the correct temperature without using too much energy.

To work out your approximate costs, multiply the hours you're using the heater with the energy output you're using in kilowatts to get the kilowatt hours used (kWh). This is what utilities companies use to calculate your costs.

Find out what your tariff charges you per kWh and multiply this and you'll arrive at the figure your heater will cost you to run.

For example, if you use a 2kW fan heater for an hour every morning and you pay 24.5p per kWh, then you can expect to spend roughly £3.50 every week on electricity for your heater.

However, our tests showed the maths isn't often exact. Most of the electric heaters we tested are listed 2kW but they often have moments of using slightly more power to get going, and after monitoring how much energy they used from being used on full blast for an hour, the costs varied from 8p to 76p.

Read our full explainer about how much electric heaters cost to run and if they're cheaper than using central heating.

Why does a thermostat matter?

It hasn't always been mandatory for electric heaters to have temperature sensors, but now it is. This is because of EcoDesign Lot 20, legislation that affected the design of electric heaters in order to create a minimum standard for energy efficiency. 

Because of this, every heater you buy can detect the temperature of the room and adjust its output to ensure a stable room temperature.

However, it's not easy to manufacture a heater that can detect the temperature easily because the thermostats on heaters are so close to the heat source (ie them). 

Thermostats have to account for this when they sense the ambient temperature of the room. There's a lot of room for failure.

A poor thermostat can lead to a range of bad consequences which increase wastefulness.

• Poor sensors mean the heater doesn't adjust its output according to the ambient temperature because it will struggle to detect it. This might mean that it's generating too much heat or not even generating heat at all. 
• Poor temperature stability will mean that the heater's output drifts from too low to too high, which is not only uncomfortable but will see your bills running up.

It's also tricky to tell what setting you've got the thermostat on on most cheap electric heaters. The thermostat tends to be a dial that goes from cold to hot, rather than listing specific temperatures in degrees 

Effective thermostatic control gives you heat when you need it, in the correct proportions. This reduces waste and maximises energy efficiency.

We've tested smart radiator valves to help you get the perfect temperature for your central heating. Read our smart radiator valve reviews to find the best.

Which is the least wasteful type of electric heater?

There are four types of electric heater: fans, convectors, oil/oil-free radiators and halogen heaters. They each have different strengths and weaknesses. 

The truth is that no type is automatically more sustainable than another and they're all capable of converting electricity into heat efficiently. 

But different heaters suit different users and you can avoid waste by using the heater that best suits your needs.

• For quick heating you want to use a fan, which generates heat and then blows it around. This means you're warmed up while you're getting ready in the morning, or if you need a boost after coming in from the cold. It would be wasteful and unhelpful to turn a radiator on which takes half an hour to warm the room up if you just need a quick blast.
• For longer heating convectors, oil and oil-free radiators excel, and warm the whole room evenly. Oil radiators even provide heating when they're turned off because their oil, which functions as a heat reservoir, retains heat.
• For heating that makes you toasty you'll want a fan that blows hot air on you, or an oil/oil-free radiator or a halogen heater that provides thermal radiation that heats objects (including your body) directly.
• For quiet heating you'll want a radiator or convector, because a fan could make such a racket that you don't want to use it.

How do I buy an eco-friendly heater?

• Consult our electric heaters reviews. Our test programme values heaters that heat quickly and thoroughly with minimal energy consumption. This means that our recommended heaters are most likely to be the least wasteful and our lowest scoring will have you wanting more while they guzzle electricity.
• Buy a heater with heat outputs you can toggle between manually You don't want to be stuck with a heater running at 2kW if 0.8kW would do for a small room. The more settings there are, including a timed switch-off, the more control you'll have to optimise your usage.
• Be wary of so-called 'eco' settings because these are often just a lower kW settings This is good to have, but a heater with four adjustable outputs is better than a heater with two where one is called 'eco'. It's better to look beyond the marketing hype here.
• Be careful if you're thinking about buying a second-hand heater. This requires trust in the seller and checking on your rights, because faulty or broken heaters can be wasteful at best and dangerous at worst. We've seen heaters being recalled because they're a fire risk when their components fail.

Find out how to make savings throughout your home with our guide to 10 ways to save on energy bills.

Can I repair my electric heater?

There's a market for spare parts for some electric heaters. Components such as bezels, heating elements, thermostats, castor wheels and more may be available.

But knowing what has gone wrong with your heater can be hard to work out – disassembling it can be harder yet. 

And, if it's within warranty, then taking your heater apart will affect your rights depending on the terms of use. 

If you aren't confident repairing your heater, you should hire an electrician or take it to a repair shop to have it looked at.

Right to repair laws don't cover electric heaters at the moment, so spare parts and access to components aren't guaranteed by law.

How do I dispose of an electrical heater?

According to Recycle Now, around one million tonnes of electrical and electronic waste are generated every year. Every item that has either a plug, a charger, batteries or carries a crossed-out wheelie bin logo can be recycled - this includes electric heaters.

You can take your old heater to your local recycling centre or see if your local council offers a household collection service for small electrical items. Double check the weight and dimensions of your electric heater to see if it qualifies. Some heaters are small desk-sized gadgets, while others are large units.

It's especially important to dispose of an oil radiator carefully because oil pollution is ecologically destructive and oil that leaks on to the ground will have a suffocating effect on plants and creatures. 

Oil is treated as a hazardous waste and needs to be disposed of locally at your nearest recycling centre that accepts it. Your council should offer advice online about where you can drop it off.

If you bought a used electric heater, read our guide to your rights when buying second-hand goods. 

Or, find out more about how to recycle electrical items.