Gas boilers are a common type of central heating system in the UK.
Using gas, the boilers heat water and use it for space heating or send it to the taps and showers.
The system can also store the heated water in the hot water tank for future use.
The system contains a combustion chamber that burns the gas and produces the heat needed for heating the water to 70°C using a heat exchanger.
Are Gas Boilers Dangerous?
Whether gas boilers are dangerous or not depends on the condition that they’re operated.
Natural gas generally burns yellow when burned without enough oxygen.
Burning of ‘yellow’ emits carbon monoxide, a dangerous toxic gas that can be deadly if haled for long.
To prevent this, it’s usually best to install a carbon monoxide detector for safe use of the boilers.
Also, regularly checking the boilers helps keep it in good condition.
Types of Gas Boiler
Gas boilers are classified into four: combination, system, regular, and combined heat and power boilers.
The combination boiler, also known as a combi boiler, differs with the absence of a water tank to store water.
The system can only supply hot water to the tap and shower immediately the water is heated.
System boilers: these have two tanks: a cold water tank and a hot water tank that stores hot water for later hot water needs.
Regular boilers: regular boilers are very similar to system boilers but have variants – vented and unvented. While vented regular boilers have one cold water tank, the unvented variant has two cold water tanks.
Combined heat and power (CHP) boilers: though it’s not common, it’s a boiler type. This is a dual-purpose system that functions as a heater by generating hot water for the home and generating electricity for the home.
We’ll talk more about the common types of boilers later in this guild.
Are Gas Boilers Efficient?
Gas boilers are efficient but require adequate maintenance.
They should be replaced every 12 years since not all spare parts are available.
Also, since gas boilers’ efficiency reduces with time, replacing them means higher efficiency.
Your gas boiler’s efficiency also depends on its type.
Condensing gas boilers are more efficient (90%) than non-condensing boilers (90%).
Gas boilers installed before 2002 are commonly non-condensing gas boilers.
Owners can program their gas boilers to work only at specific times.
This ensures that your boiler doesn’t run when there’s no demand for hot water.
You can also install a thermostat to monitor the temperature in your property and trigger the boiler to run.
It’s also common to maximize the system’s efficiency by installing a thermostatic radiator valve in each room of the home.
The major advantage of a condensing boiler over a non-condensing boiler is higher efficiency.
Condensing boilers have higher efficiency than their non-condensing counterparts.
Ever since they hit the UK about 20 years ago, condensing boilers have been the most energy-efficient gas boilers.
Benefits of Condensing Gas Boilers
High energy efficiency: they help save money than non-condensing boilers since the former have higher efficiency than the latter.
Environmentally friendly: the UK is gradually shifting from high-carbon emission systems, and therefore, condensing gas boilers with lower CO2 emissions are preferred.
Less cycling: condensing boilers work with the home’s heat demand. With this, they turn off when the home doesn’t need heat, reducing gas consumption.
Lower fuel bills: though the initial installation cost might be high, condensing gas boilers help save money in the long run by burning less fuel.
Compact size: these boilers are smaller in size, and the use of modern materials makes them a suitable option for homeowners looking for something aesthetically pleasing.
How Condensing Gas Boilers Work
High efficiency is achieved with condensing gas boilers in two ways: the boiler consumes less gas to produce heat and minimises heat loss.
Condensing gas boilers don’t lose as much heat as in traditional condensing gas boilers.
They recover much heat and reduce heat loss through their bigger heat exchangers.
Market Developments of Gas Boilers
For decades, gas boilers have been the ‘talk of the day’ in Europe, dominating heating technologies.
Non-condensing gas boilers were the first to hit the market and had a great welcome.
They enjoyed a great time not until 2002 when condensing gas boilers were introduced, and before 2002, the new boilers earned 18% of the total gas boiler installations in the UK.
In 2016, condensing boilers had taken the lead and were having 80% of the installations, thanks to their high efficiency (90%).
Hybrid Heat Pumps and Gas Boilers
A Hybrid heat pump is a combination of gas boiler heating and ASHP (Air-Source Heat Pump) to make a single unit.
With this, the gas boiler can act as a backup for the ASHP.
This helps generate heat for the home at a lower cost and reduces the home’s chances of running out of heat when needed.
An electric control system is added to this combination to maximize efficiency.
The control ensures that the combined systems only run when there is heat demand in the home.
While this maximizes efficiency, it also helps save money on fuel.
Types of Gas Boilers
There’re many types of gas boilers on the market, and the right one for your home depends on certain factors, such as the size of your home, the number of showers, bathroom, baths, and the age of the house.
However, there’re three common types of gas boilers on the market.
Though your installer would know the best type of gas boiler for your home and demands, it’s worth knowing the available types of gas boilers and their advantages, so you know what to expect.
Also worth noting is that the law only allows condensing gas boilers in Ireland.
So, whether you’re installing a combi, system, or regular boiler in Ireland, ensure it’s a condensing boiler.
This can perhaps be attributed to the high efficiency of condensing gas boilers.
Again, condensing boilers have 90% efficiency, meaning that they utilize 90% of the energy supplied and only 10% is wasted.
Here’re the common types of gas boilers.
Regular gas boilers are also known as heat only boilers and can supply hot water to many taps and showers simultaneously.
They contain a hot water tank and a cylinder. Being able to carry the hot water needs of several rooms, they’re a great option for large families.
Regular boilers are more suitable for homes with a traditional heating system connected to a separate hot water cylinder.
To maintain the water level in the central heating system, regular gas boilers require a cold-water storage tank and a traditional tank.
If you own a regular boiler and are considering replacing it, it’s best to replace it with the type you’re currently having.
Replacing your old regular gas boiler with a different type might be costlier and with reduced efficiency.
Also worth noting is that regular boilers work with all types of solar heating systems.
Advantages of a Regular Boiler
- Allow more than one hot water source at a time
- Compatible with areas with low water pressure
- Works with solar systems
Disadvantages of a Regular Boiler
- It requires a storage tank and a hot water cylinder
- There is a delay when waiting for the water to heat up
- It can run out of hot water
System boilers are another common type of gas boilers in the UK.
While they also use a hot water cylinder, system boilers don’t require a water tank.
Also, since they have a pump and expansion vessel, they don’t need a header tank.
They’re more suitable for homes without an attic but with many bathrooms with large hot water demands.
Advantages of a System Boiler
- It has low running costs
- It can supply water to many taps and showers at a time
- It doesn’t require an attic or storage tank
- It can work efficiently with solar systems
Disadvantages of a System Boiler
- It might be delaying having to wait for the water to boil
- It can run out of hot water
- How much water to supply depends on the tank
- It requires a cylinder
As the name sounds, ‘combination’ boilers are a combination of a central heating boiler with a high-efficiency water heater.
These boilers heat water coming directly from the mains only when hot water is needed.
This also means that the system doesn’t need hot water storage, such as a hot water cylinder.
Since the system doesn’t require storing water in the hot water cylinder, it also means no heat is lost in the cylinder, hence high efficiency.
Today, most UK homes choose combi boilers for their high efficiency.
Advantages of a Combi Boiler
- No need for a hot water cylinder
- It heats water immediately with no delay
- Limited pipework
- Compact size
Disadvantages of a Combi Boiler
- It requires high water pressure
- It cannot supply hot water to more multiple baths/showers at a time
- Not suitable for large families
- Water pressure reduces with leaks
- Not always suitable for power showers
- Reduced water flow when heating the water
What to Know Before Installing a Gas Boiler
A gas boiler is generally not a cheap investment.
Hence, it’s smart to do your research before investing your money in it.
If you’re planning on buying a gas boiler, here’re what to take with you.
Consider the Manufacturer
Different boiler brands now flood the market.
When looking for a gas boiler, you’ll come across many models.
Be wary of buying a cheap boiler, as most of them are from new brands in the industry.
Rather, choose a boiler from a renowned brand.
Buying from a renowned manufacturer means you’re investing your money in products that other people have used before and can vouch for.
This prevents frequent repairs of your gas boiler.
While you can use the internet to search for information, you can also ask your neighbours about their gas boiler’s brand and how efficient and how long they’ve been using them.
What Is The Right Boiler Size For My Home?
The right gas boiler’s size for your home depends on a number of factors, such as your home size and demand.
Choosing a boiler smaller than your energy demands lets the boiler overwork, gradually shortening its lifespan.
Also, you don’t want to choose a gas boiler too large than your energy needs, as this consumes much energy, running up your electricity bill.
Gas Boiler Maintenance Tips
Although inviting a professional to inspect your boiler is key, there’re a few tasks you can carry out on your boiler yourself.
Here’re a few maintenance tips to keep your boiler in good condition and help maintain its lifespan:
- Invest in an annual boiler service
Though your system may look good on the outside, regularly hire a Gas Safe registered engineer to inspect it for you. Doing this alerts you of possible future faults that your boiler is likely to develop.
- Turn your heating on regularly
Grit always gathers in the boiler pump that is kept unused for long. To avoid this, ensure you use your boiler at least once in a month. Even in summer, turn the system on for about 15 minutes. This helps reduce the chances of a breakdown.
- Check the boiler pressure
Also worth doing is to check your boiler’s pressure gauge level regularly. This lets you know if it needs topping up. The reading should be at least above one bar. When the reading is below one bar, it calls for depressurizing your boiler.
- Bleed the radiators
Bleeding your boiler’s radiator before the cold weather hits is important to ensure that your heating system runs efficiently. If you notice any cold spots on them, air might be trapped inside, hence the need for bleeding.