Gas Boiler: Which is the best type for your home?

Gas boiler and bills

With so many gas boilers on the market, it can be difficult to choose the right one for your home. In this article, 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 maximize your savings.

Gas Boiler Types

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:

  • 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 (coming soon!).

  • Regular or 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.

  • 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.

What are the pros and cons of the different gas boiler types?

Let’s examine some of the advantages and disadvantages of the different gas boiler types.

Combi Gas Boiler Pros and Cons

We break down some pros and cons of having a combi gas boiler below.


  • 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 Regular or Traditional Gas Boiler

Here are the advantages and disadvantages 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

The main attributes of the system gas boiler here.


  • 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:

Which is the best gas boiler on the market?

gas boiler

As you can see from the above advantages and disadvantages, the best gas boiler to have will largely depend on the size of your home and the usage.

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.

Best gas boiler for smaller homes

The Worcester Bosch 30kW is quite popular, has good customer reviews, and is priced at a little over €2,500. 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.

Best gas boiler for larger homes

Once again in this category, we see the same brands come up, Ideal IDEAL Logic 18kW, currently priced at just over €1,900, versus the Worcester Bosch 18kW, which goes for a little over €2,300.

Other important factor

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.

  • 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.
  • 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.
  • 30kw or higher – These large gas boilers can furnish enough power for up to twenty average-sized radiators and a hot water cylinder.

A combi boiler would require a slightly higher size to work efficiently as it provides ‘on demand’ hot water. Most combi boilers would start at 24kw.

Are gas boilers going to 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.

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.

The first obvious option is electrical 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.

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 grants for upgrading to a condensing oil boiler. These have a lower carbon footprint than traditional oil boilers.

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.

Gas Boiler Maintenance

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.

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