In the past, gas boilers were the only home heating option available, but now, there are plenty of options to choose from, including electric boilers, heat pumps and hydrogen-ready boilers, each of which have their own advantages and disadvantages.
If you’re thinking of replacing your old gas boiler with something else, you may want to consider an electric boiler. But before you jump into this decision, it could be a good idea to do some research around the differences between these two types of systems and the impact each one could have on your home’s heating and efficiency.
Fig 1. Electric Boiler
The main (and most obvious) difference between gas boilers and electric boilers is the type of energy they use in order to produce heat.
A gas boiler takes in natural gas from the main supply and burns it in the heat exchanger. As the gas is burned, it heats up and can be passed through pipes that are surrounded by cold water. When the hot gas moves through these pipes, the surrounding water is heated up and either pumped around your radiators or directed to the hot water tank.
For properties that aren’t connected to the mains gas supply for any reason, LPG tanks can be installed somewhere on the property. These tanks contain liquified petroleum gas (LPG), essentially a liquid that a gas boiler can burn, and need to be refilled when they’re low in volume.
Gas boilers can either heat the water and store it in a tank for when it’s needed (conventional systems) or heat the water on demand without the need for storing it (combi boilers).
Electric boilers, on the other hand, use electricity to heat cold water. The energy is applied to an internal heating element that gets very hot, heating the surrounding water much like a kettle. This makes these appliances good for homes without a gas supply.
Each of these systems has its own advantages and disadvantages, and the choice you ultimately make can depend on your heating demands, your home and running costs.
It’s generally thought that gas boilers are cheaper to run because the cost of gas is currently around four times lower per kilowatt hour (kWh) than that of electricity. Gas currently costs around three to four pence per kWh, whereas electricity costs around 14 to 15 pence per kWh although prices seen rising to 17 pence per kWh in September 2021.
|Electric boiler size||Run time (hours)||kWh usage per day||Run time (days)||Total heating usage|
|2 kW||*||7.5||=||15 kWh||*||150||=||2,250 kWh|
|6 kW||*||7.5||=||45 kWh||*||150||=||6,750 kWh|
|10 kW||*||7.5||=||75 kWh||*||150||=||11,250 kWh|
|14.4 kW||*||7.5||=||108 kWh||*||150||=||16,200 kWh|
Using this information and an assumed electricity cost of 14.4 pence per kWh, it would cost around:
Based on the above, we can see that it’s cost-effective to run a small electric boiler, but that large electric boilers can be very expensive to run.
Below, we’ve worked out the total usage in kWh of the four main sizes of boiler.
|24 kW||*||7.5||=||180 kWh||*||150||=||27,000 kWh|
|30 kW||*||7.5||=||225 kWh||*||150||=||33,750 kWh|
|35 kW||*||7.5||=||262.5 kWh||*||150||=||39,375 kWh|
|42 kW||*||7.5||=||315 kWh||*||150||=||47,250 kWh|
You can see here that the kWh usage per year is much higher with a gas boiler than an electric boiler, however, as the cost of gas is cheaper, it doesn’t work out that much more expensive.
Using this information and a gas cost of 3.80 pence per kWh, it would cost around:
What we can take from this information is that electric boilers may be cheaper to run for smaller homes or homes that have a lower demand for heat, whereas for larger homes that use a lot of hot water, a gas boiler is likely the cheapest option. These things will also depend on your provider and the standing charge amount.
Now that we’ve established the running costs of each type of system, it’s important to understand some of the other advantages and disadvantages of gas boilers vs. electric boilers.
Generally, electric boilers are cheaper to install than gas boilers because there’s less work involved and they don’t require a flue or connection to a gas supply.
An electric boiler is a good choice for one of the two million homes in the UK that aren’t connected to a gas supply.
Electric boilers are highly efficient because no gas or other waste products are produced, keeping the energy usage focused purely on creating heat. For this reason, electric boilers have a very high efficiency rating of up to 99 per cent.
Electric boilers are generally more environmentally friendly than gas boilers as they don’t produce fossil fuels from the burning of energy. However, it’s still worth noting that fossil fuels are still burned in order to generate electricity, so electric boilers aren’t completely carbon-zero.
If your home has solar panels or a domestic wind turbine, the energy created by these renewable sources could be used to power your electric boiler, and therefore heat your home.
Electric boilers are often smaller than their gas counterparts and run much more quietly, too, as they have fewer moving parts.
As an electric boiler uses electricity, there’s no risk of unburned gas or waste gas entering your home.
As an electric boiler has no flue or gas pipe, it can be installed almost anywhere in your home.
While the benefits above sound amazing, it’s worth nothing that there are some downsides to an electric boiler.
As we revealed earlier, electric boilers may not be suited to large homes or homes that have a high heat demand. This is because they can become very costly to run.
An electric boiler might not be able to fully meet your heating needs at all. They don’t cope well with large outputs and so your radiators may not reach the temperature you require, or you might run out of hot water sooner than expected.
Gas boilers are still a viable option for your home if you’re unsure whether an electric system is for you.
Gas boilers are still the most popular home heating option in the UK, and so there’ll be a wide range of Gas Safe Registered engineers who can install them and these appliances might be more readily available. There may also be more choice when it comes to gas boilers, with more models and manufacturers to choose from.
If you already have a gas boiler, it’s likely going to be easier to replace it with another similar, newer model with little disruption at home.
Gas boilers may be better at coping with high heat demands, so for homes that have lots of bathrooms and/or numerous radiators, a gas boiler is likely the appliance for you. As we’ve already uncovered, gas boilers are cheaper to run than electric boilers in larger properties.
It can be more expensive for a gas boiler to be installed as it needs to be connected to a flue and a gas supply and tested for gas leaks.
Gas boilers can be bigger and noisier than electric boilers. They have more moving parts, which means there’s a higher chance of something breaking or going wrong, which can cost money to fix.
If you do choose to make the switch from a gas boiler to an electric boiler, your old heating system will need to be removed and replaced with the new one. While any water pipes can stay in to deliver hot and cold water around the property, the gas boiler and gas pipes will need to be removed, and the boiler will need to be decommissioned too. These things should only be done by a qualified heating engineer with the proper credentials.
In some cases, the old gas pipes might be capped off rather than removed completely, which could save a lot of mess.
Once the gas engineer has taken care of removing the old boiler and decommissioning the system, an electric technician will be required to come and install the new electric system. It can be installed in the same place as the old boiler, but you can also choose a new location for it as it doesn’t need to be connected to a flue.