Gas Boiler: Which Is the Best Type for Your Home?

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Gas boiler and bills

A gas boiler is a home heating system that uses natural gas as its main fuel and are the most popular boiler type in Ireland, which over 80% of Irish homes using one for their heating. In our Gas Boiler guide, we have a look at the different factors to consider when choosing a gas boiler, provide suggestions on the best ones, and look at other important tips so you can maximise your savings.

What Is a Gas Boiler?

gas boiler

A gas boiler is a home heating system that uses natural gas as its main fuel. Gas boilers are the most popular boiler type in Ireland, which over 80% of Irish homes using one for their heating. Since they rely on natural gas, they can often be a cheap and efficient way to get heat around your home, and there are a lot of resources and boiler servicing options to choose.

What Gas Boiler Types Are There?

When choosing a gas boiler, it’s important to know the different types of gas boilers that are available on the market. Below, we break down the three main types of gas boilers in Ireland:

  1. Combi Gas Boiler
    The combi gas boiler has two functions: it heats your water for domestic use and also works as your central heating system. These gas boilers tend to be more compact than other types as they do not need a tank to store the hot water. For more information, head to our complete guide on combi gas boilers.
  2. Traditional Gas Boiler
    This type of boiler needs to have a separate cold water tank to feed it as well as a cylinder to store the heated water. They are referred to as ‘regular’ as they are the most common type of gas boiler in Ireland and have been around for a long time.
  3. System Gas Boiler
    A system gas boiler is similar to a regular gas boiler in that it still needs a separate cylinder to store the hot water. However, it does not need to be fed by a cold water tank. This makes it less bulky and less expensive to install versus a regular gas boiler.

Which Is the Best Gas Boiler on the Market?

As a rule of thumb, any small home or flat with only one bathroom will benefit greatly with the use of a combi gas boiler. Its ‘on demand’ feature makes it incredibly efficient and has little to no waste. It is also compact, which many small homeowners will appreciate.

Any larger home of three bedrooms or more should consider at least a system or regular boiler. A system boiler does not require as much space, which can be an important advantage over the regular boiler.

gas flame

What's the Best Gas Boiler for Smaller Homes?

The Worcester Bosch 30kW is quite popular, has good customer reviews, and is priced at a little over €1,000. It is slightly more expensive than other brands but may be worth it for the longer warranty.

The Ideal Logic 30kW and the Glow-worm Combi 30kW are two other combi boiler brands with positive customer reviews. They are priced at around €2,300. Again, the main difference between the three brands is the length of the warranty.

What's the Best Gas Boiler for Larger Homes?

Once again in this category, we see the same brands come up, IDEAL Logic 18kW, currently priced at just over €1,900, versus the Worcester Bosch 18kW, which goes for a little over €2,000.

What Other Important Factor Are There?

Whether you should choose a system or a regular boiler depends on the existing system in your home. Staying with the same system is often easier and more economical.

What Size Gas Boiler Should I Get?


Gas boilers come in all sizes. While some experts may try to encourage you to get a gas boiler that is larger than necessary in order to compensate for the heat loss, it’s best to use the guidelines below when choosing which size gas boiler to get.

Note that a good thermal insulation blanket can address any concern for heat loss issues rather than paying for a larger size boiler.

  1. 15-18kw
    This is usually an ideal size boiler for smaller homes and flats. They can supply approximately ten average-sized radiators and a hot water cylinder.
  2. 18-24kw
    This size boiler is mainly found in three to four-bedroom homes. They can sustain energy for approximately fifteen average-sized radiators and a hot water cylinder.
  3. 30kw or higher
    These large gas boilers can furnish enough power for up to twenty average-sized radiators and a hot water cylinder.

Will gas boilers be banned?

The Irish Government has announced that by 2025, gas boilers, as well as oil boilers, will be prohibited in any new builds. This is part of an action plan to reach carbon net-zero emissions in line with the Paris Agreement.

man thinking lef

Are There Alternatives To Gas Boilers?

Since gas boilers will be removed in Ireland by 2050, one may want to start looking at alternatives to gas boilers.

Are Electric Boilers a Good Replacement?

The first obvious option is electric boilers. With the price of electricity continually on the rise recently, it may not sound too appealing at first. However, there is usually little energy loss compared to gas boilers and electric boilers do not require a flue or escape for the exhaust gases. These attributes make electrical boilers an attractive alternative.

What About an Oil Boiler?

One could also consider getting an oil boiler as these are the last few months one could do so. The Sustainable Energy Authority of Ireland (SEAI) offers boiler grants for upgrading to a condensing oil boiler. These have a lower carbon footprint than traditional oil boilers.

Are There Other Boiler Options?

Then there are LPG gas boilers. These will also be banned from being installed in new builds from 2025. They are similar in cost and efficiency to oil boilers.

With both gas and oil boilers set to be replaced by 2025, one may want to consider going ahead and replacing their existing boilers. For more information, check out our guide on our gas boiler replacements.

What Is Gas Boiler Maintenance Like?

Whichever gas boiler you end up choosing for your home, having it maintained yearly is key to ensuring that it will continue to operate flawlessly for many years. Whether you choose to have a maintenance plan or pay for the service as needed, the yearly savings on the quantity of gas used on a well-maintained boiler is considerable. For further savings, you will also want to ensure you have a good plan for your gas unit rates. For safety, you should also consider getting a carbon monoxide alarm.

What Are the Pros and Cons of Gas Boilers?

Since gas boilers have a lot of variety compared to other different boiler types, it's not easy to compare them as you would with other boilers. We've broken down the pros and cons of each gas boiler type to give you an overview of what each has to offer:

Combi Gas Boiler Pros and Cons


  • Compact and doesn’t occupy much space
  • Operates ‘on demand’ and is, therefore, economical to run
  • Easier to install and requires less pipework than other systems


  • The complex set-up makes it costly to repair in case of breakdown
  • Less efficient in homes with high hot water demand, i.e., running two showers at the same time
  • Will no longer be permitted in new builds from 2025

Pros and Cons of the Traditional Gas Boiler


  • Great for high hot water demand homes such as homes with multiple bathrooms
  • Good in low water pressure homes
  • Suitable with solar water heating panels


  • Higher risk of leaks and water damage with the need of two water tanks
  • Requires more space than the other two gas boiler systems
  • Not as efficient due to loss of water heat sitting unused in the water tank

System Gas Boiler Pros and Cons


  • Can supply hot water to multiple taps at the same time
  • Does not use any loft space like the traditional gas boiler
  • Suitable with solar water heating panels


  • Need for water tank increases risks of water leak and damage
  • Bulky as it still requires space for a cylinder tank
  • Not as efficient due to loss of water heat sitting unused in the water tank.

Need help comparing other types of boilers? Check out the following boiler guides for more information:

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