Guide written by:
Dennis, self-taught DIYer, Bristol
From convection to radiation, storage heaters to thermal inertia radiators, it's easy to lose your way when looking for a new electric heating system. Luckily, we have a range of tips and tricks to help you find the best electric heater or radiator to warm up your home.
- Heat transfer
- Energy consumption
- Programming and smart control
- Room type
- Room volume
Choosing an electric heater or radiator: the essentials
If you're looking to purchase several heaters, take the time to carefully weigh up your options, compare models, and make use of a programming system (pilot wire, energy management system, etc.). Finding the right heater or radiator will depend on a combination of factors.
- The room where it will be installed: a bathroom won't be heated the same way as a bedroom, for example.
- Thermal comfort: important for general well-being, this will depend on the type of heat transfer provided by your system.
- The time a device takes to heat up will depend on the room in which it is used as well as the habits of the user.
- The volume of the room you want to heat and how well your home is insulated: large, poorly insulated homes will require a lot of energy to heat.
- Budget: there can be a discrepancy between the perfect model and your bank balance!
Thermal inertia radiators work best for living spaces as they are cost-effective and distribute heat evenly. If you do not have a timer for your bathroom heater, pick a model with a fan system. A heated towel rail fitted with a fan heater, for example, will ensure faster heat-up times. Hallways and kitchens can usually get by with a radiant or convector heater as they are not in constant use. Nonetheless, thermal inertia heaters will generally provide a more efficient option, regardless of room type.
To calculate how much power you need from your heater, multiply the surface area in m² by 100 W for poorly or moderately insulated homes or by 60 W for homes that are very well insulated. For bathrooms, multiply the surface area by 125 W.
Thermal comfort is linked to the way in which the heater or radiator distributes heat. The greatest level of comfort is provided by thermal inertia radiators, both in terms of heat and energy consumption. Convector heaters are inexpensive but use a lot of energy and do not provide the most pleasant form of heat. A fan heater will be able to heat a bathroom or small room in around three minutes flat. But pay attention your energy bill because these devices can really rack up on the meter! With this in mind, these devices should only be used occasionally. A radiant heater can be installed in a room that is only used from time to time. These devices produce a similar kind of heat as sunlight: the closer you are to them, the warmer you'll be.
For a point of reference, a constant temperature of around 19°C is recommended for living rooms while 16°C is best for bedrooms. Bathrooms should ideally be kept at around 17°C while not in use and 22°C when they are.
Types of electric heaters and radiators
Electric heating systems are split into three categories according to the type of heat transfer used: convector heaters, radiant heaters and thermal inertia radiators.
Electric convector heaters
Convector heaters heat the air directly using an electric element. The heated air rises and is replaced by incoming cool air which, in turn, is then heated. The heat is distributed through the room by the movement of this air in a process known as convection. As a result, the air dries out somewhat. What's more, the space will heat up unevenly and the circulation of air can move around dust.
Convector heaters are best suited to well-insulated hallways as they heat up quickly. Opting for a model equipped with a fan will ensure very fast heat-up. As convector heaters tend to dry out the air, it is recommended to use them alongside a humidifier to increase the humidity rate of the room. These devices may also reduce the amount of negative ions in the air, which are thought to enhance well-being.
Electric panel heaters
Electric panel heaters produce infrared waves which provide a similar type of heat to sunlight exposure. These heaters therefore work by radiation but also transfer heat through convection. Electric panel heaters heat up any objects surrounding them including furniture, walls and people, which may not provide the most comfortable sensation.
The primary method of heat transfer is, therefore, radiant heat. If the heat is released by an aluminium panel heated by electric elements, it is referred to as far-infrared; if the heat is produced by a halogen lamp, it is known as near-infrared. The downside of these heaters is that they stop producing heat as soon as they are switched off. However, some models are therefore equipped with a device used to store heat and release it over time. These heaters are called thermal inertia heaters.
Fan heaters are electric heaters that are essentially only used as additional heat sources or as the sole heating source in a bathroom as they are able to heat up small rooms in record time. These heaters are equipped with a fan system which releases heat generated by an electric element. Some fan heaters are fitted with ceramic heating components which makes them more cost-effective to run. Often splash-resistant and equipped with a timer, fan heater technology may be used in combination with convector or radiant heaters to allow these devices to heat up more quickly; this is especially useful in bathrooms.
Thermal inertia radiators
Thermal inertia radiators offer the most cost-effective option. The energy produced by these radiators is stored in one of two ways: in a thermal fluid (glycol, oil, etc.), in which case the heater is referred to as a thermal fluid radiator; or by a solid material such as ceramic or soapstone in which the device is referred to as a dry inertia radiator.
This energy is created via a heating element which is stored within a material. The most common type of inertia heaters are storage heaters.
Modern inertia radiators
Many modern inertia radiators are made up of a radiant panel on the outside that is heated up by one element and a core heating component powered by a second element. The advantage of these devices is that they heat up quickly thanks to their radiant outer panel and are able to store heat using their thermal heating core. While they are powered by electricity, they do not dry out the air and produce a similar sensation as central heating. These heaters are usually made of cast iron or aluminium. Cast iron is very good at retaining heat while aluminium heats up quickly.
Storage heaters are made of a heat-resistant material. They are so efficient at storing heat that the heat that they gather overnight can be released throughout the next day without the heater having to draw any more power. Storage heaters work on the same principle as more modern inertia radiators: they stock heat that they distribute later on. The difference is that storage heaters usually have a much greater storage capacity than the average inertia radiator. These heaters store up heat during off-peak hours at night and release radiant heat at peak times during the day. The main drawback of these heaters is their weight and size.
Solid heating core or thermal fluid
The way thermal inertia heaters heat up and store heat will vary depending on the type of heating components they contain.
Some radiators that are filled with a thermal fluid. These models heat up faster than dry inertia heaters and are also lighter. This fluid may consist of glycol, mineral oil or a vegetable oil. Thermal fluids are, however, less effective at storing heat compared to solid materials. What's more, leaks can occur over time. Oil filled heaters are the portable versions of thermal fluid radiators.
Ceramic core electric radiators
Ceramic is better at retaining heat than thermal fluids but these radiators take longer to heat up. This material offers one of the most effective form of thermal inertia as it is very good at retaining heat. A ceramic core is used to store the heat and release it gradually and evenly. These radiators offer maximum thermal comfort and significant energy savings as heat loss is minimal.
Soapstone core radiators
Soapstone is a type of metamorphic rock with high thermal conductivity. It is able to store a lot of heat over a small surface. These heaters are cost-effective as they will continue to distribute heat even after they are switched off. Be wary of any soapstone mixed with cement , however, as this material does not have the same characteristics as pure soapstone and will not store heat as well.
Cast iron is an alloy of iron and carbon. A heavy material, cast iron is excellent at storing heat but is rather slow to heat up. This type of heater will help to maintain air quality. Nonetheless, these models must be set up with an insulating material fitted behind the radiator itself. This is due to the fact that this type of device does tend to heat up from behind and will heat up the wall.
Oil filled heaters
Comparing electric heaters and radiators
Convector heaters are not expensive to purchase but they will not heat up a room evenly. They rely on the circulation of cool air that is released as warm air when heated by electric elements.
That said, they will reach an ideal temperature in just a few minutes.
Nonetheless, the warm air generated by convection will release dust into the air. These devices are therefore not recommended for those with allergies.
Electric panel heaters
The infrared waves from radiant panels heat up all objects around them meaning they can reduce any humidity in the walls and transfer heat directly to people. This type of heat spreads evenly and is quick to achieve, but there is no air movement. The main advantages of these heaters is the pleasant form of heating they offer and the fact that they heat up quickly.
Electric panel heaters are, however, not recommended for use in bathrooms with tiles or in any room containing a lot of glazed surfaces, such as greenhouses or conservatories. In this case, it's best to use a halogen heater. These heaters are more direct, generally set up closer to people and are therefore less energy intensive.
Thermal inertia radiators
These radiators are slow to heat up but once they have reached their peak they will distribute heat constantly and and durably, even after they are turned off.
A modern inertia radiator will usually be your most cost-effective option. They also provide the best solution if you are installing electric heating in a new building or overhauling your whole heating system. Up-to-date models are recommended for the most thermal comfort.
Advantages and disadvantages of electric heaters
Electric heater or radiator
Quick heat-up; pleasant form of heat;
Inexpensive; quick heat-up;
Even and steady form of heat; powerful radiant heat;
No thermal inertia; dries the air;
Takes a long time to heat up; thermal fluid has potential to leak; heavy and bulky; heats from two sides
Different types of thermostats
The purpose of a thermostat is to turn your electric heating on and off according to a set temperature. Electric heaters will all come with a thermostat; however, the accuracy of the device will differ from model to model.
Mechanical thermostats are able to maintain a set temperature and are accurate to around 2°.
These thermostats are best suited to convector heaters.
Electronic thermostats maintain a set temperature with an accuracy of 0.5°. This is a great option as you won't waste any energy. The temperature settings are also more precise.
Digital thermostats are even more accurate and temperatures can be set with an error margin of just 0.1°.
Smart control: a new way to use your electric radiators
Thermostats can be controlled manually via a built-in control panel or remotely using a programmer.
Smart control allows you to control your heaters using more advanced functions such as open window detection, motion detectors, consumption data, etc. This option allows you to manage your energy consumption from each electric heater.
In addition to enhanced user comfort, smart control can allow you to make savings of up to 45% compared to use of a basic convector heater alone.
Manage your energy consumption
Wireless control allows you link up your heaters to create a centrally controlled heating zone using either Bluetooth or Wi-Fi.
The latter easy-to-use system allows you to control your heaters online.
Choosing the right electric heater for your room
You should think about how comfortable the type of heat transfer is, the distribution of warmth throughout the room, how quickly the space is heated and how well the temperature is maintained, and the quality of air. If you're feeling flush, there's nothing stopping you from getting top-of-the-line smart heaters throughout the house! Otherwise, you should think about the heating needs of each room.
Hallways and spare rooms
Hallways and lesser used rooms (entrances, corridors, guest rooms, etc.) can be fitted with radiant heaters. Heating up evenly and quickly, this type of heater will suffice for these spaces.
For rooms that you spend more time in (living rooms, offices, bedrooms, etc.) opt forgreater comfort with a thermal inertia heater. If possible, go for a smart control system. As these rooms will be heated often, it is advisable to go for economy heaters.
A heated towel rail is a great option for a bathroom. These devices can even be combined with fan heater technology to heat up a smaller room in less time â€“ which will make getting out of the bath all the more pleasant!
Choosing a heater for your room type
Type of heater
Thermal inertia radiators
Modern inertia heater
Heated towel rail
Thermal comfort is achieved by an efficient and well-proportioned heating system. There are a few different criteria to consider:
- Heating quality: radiation vs. convection
- Air quality: depends on the type of heat transfer; convection dries out the air and reduces negative ions which are thought to be necessary for general well-being.
- Temperature control: an over- or under-heated house on a daily basis will prove unpleasant; temperature rise should be quick and heat should be maintained evenly.
Fan heater technology
Calculating the wattage of your electric heater
It's important to choose the right power rating for your electric heater or radiator. This is given in watts (W) or kilowatts (kW); 100 W= 1kW. Wattage is linked to the surface area of the room which is indicated in square metres (m²); this is calculated by multiplying the length and width of a room. The power rating can also be referred to in terms of volume in cubic metres (m3) and is calculated by multiplying the surface area by the height of the room. Calculating the correct wattage for your heaters is important for your comfort as well as your wallet!
Factors to consider when calculating heater power
Strictly speaking, the power rating of your heating system will also depend on:
- the temperatures over the winter where you live (i.e. it will be colder in regions of high altitude);
- the quality of your home's insulation;
- the desired average temperature;
- the volume of the rooms to be heated.
Power rating according to surface area or volume
In order to calculate the right power rating for your electric heater, you have several options:
- 100 W/m² or 0.4 kW/m3for well-insulated homes;
- 70 W/m² or 0.28 kW/m3 for very well-insulated homes;
- 60W/m² or 0.24 kW/m3 forhouseholds with low energy needs.
For ceiling heights over 2.5 metres, calculate your wattage based on room volume rather than surface area.
Exposure and location
- Add an extra 5 to 10% to your calculations for homes with large glazed surfaces and/or north-facing properties.
- Add an extra 10% to your calculations for each 500 metres of altitude.
Why choose two electric heaters over one?
No matter which calculation method you go for, if the room measures over 30 m², opt for two electric heaters for better heat distribution.
Overestimating your energy needs
The majority of heaters are rated 500 W, 1,000 W, 1,500 W, and so on. It is better to overestimate your energy needs. If you have any doubts as to the quality of your insulation, you can get an Energy Performance Certificate. If necessary, you can take measures to improve the energy efficiency of your home. A properly insulated home will considerably reduce your energy bill.
Electric towel rails for maximum comfort
Heated towel rails work to heat up your bathroom and dry your towels.
Their large surface area means that they will heat up your room quickly and evenly. Manufacturers offer a range of different designs. From round to flat bars, there's something for everyone! Electric towel rails are generally good at retaining heat. They may contain solid heating components or thermal fluid.
Some heated towel rails are fitted with a fan to heat up more quickly. A great alternative to traditional heaters, these devices have become more or less standard in most modern bathrooms.
Heated towel rails
Additional options for electric heaters
Regardless of whether they are portable or fixed in place, electric heaters can be equipped with a range of options to improve safety, enhance user comfort and help you save money:
- anti-mark system: heat is diffused from the front of the device only to prevent dark marks from forming on the walls;
- open window detection which will automatically turn off your heater;
- consumption data, allowing you to keep an eye on your energy bill;
- motion detection: the temperature of the heater will change automatically if the room is occupied;
- smartphone control for easy programming;
- child lock protection: allows you to lock the controls;
- anti-tip protection for portable oil-filled radiators and panel heaters;
- overheat protection;
- frost protection setting for secondary homes;
- remote control to control your heat settings from a distance.
Don't forget to keep an eye on your electric heaters. Programming your system to align with your heating needs can help you to save a lot of money.
Choosing the right heater shape
The layout of your room may mean that you need to install a horizontal, vertical, baseboard or skirting board heater.
Electric heaters and radiators are generally horizontal in form, meaning they are wider than they are tall.
These are generally suited to most rooms and are the most commonly found models.
Vertical heaters and radiators are best suited to rooms where horizontal space is limited. However, they tend to have a maximum height of around 180 cm.
Baseboard heaters are designed for spaces that are very limited in height.
They measure up to around 40 cm in height.
Skirting board heaters
Skirting board heaters are installed at the same height as your skirting boards and generally won't be any taller than about 20 cm.
Electric heater price comparison
Thermal fluid inertia
Dry inertia radiator
Cast iron radiator
Modern inertia heater
Heated towel rail
Oil filled radiator
Guide written by:
Dennis, self-taught DIYer, Bristol, 18 guides
I started doing DIY 10 years or so ago, when I bought a house that needed to be renovated. After having installed loft isolation, and having refurbished the bathroom, the toilets, the kitchen, the bedrooms… I built an extension, installed a new fence with a gate and kitted out the house with a solar panel to make hot water. I have poured tens of tonnes of concrete into slabs or into the foundations and renovated the roof… I can say that building materials and tools are no stranger to me! If I had a pound for every hour spent looking up information in forums and DIY magazines to find solutions to my problems, I'd be a millionaire! So passing on my knowledge on tools and home equipment is natural, as it is just giving back what I borrowed.