Your guide to gas boilers

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If you're confused about gas boilers, you've come to the right place! Discover everything you need to know about gas boilers with this comprehensive Padly guide.

As trusted boiler installers, it's our job to provide you with essential knowledge about all things boilers, so that you can make informed decisions about your home's heating system. In this comprehensive guide, our experts at Padly have explored the fundamental aspects of gas boilers to give you a well-rounded understanding and help you decide if a gas boiler is right for you and your home.

Gas boiler fundamentals

To help you gain a well-rounded understanding of gas boilers, it's important that first, you know the fundamentals:

What is a gas boiler?

A gas boiler is a heating system that uses natural gas to produce hot water and central heating. The gas is burned to heat the water, which is then circulated through the central heating system to provide warmth throughout the home.

What types of gas boilers are available?

There are three main types of gas boilers: combi boilers, system boilers, and heat-only boilers. Each type has its own set of advantages and disadvantages depending on the requirements of your home's heating system. It's important to choose the right type of gas boiler for your home, taking into consideration the size of your property, the number of occupants, and your hot water demands.

How do gas boilers work?

While there are different types of gas boilers on the market, they all work in a similar way - by heating gas to warm your home. There are two ways that the gas can enter the boiler: through a main or an LPG bottle.

To find out how the three types of gas boilers work, see below:

Combi boilers

Combi gas boilers are a popular choice for smaller homes as they don't require a water tank or cylinder. The hot water produced by the boiler is pumped directly through taps and showers, providing instant hot water on demand.

System boilers

System gas boilers require a separate water tank or cylinder to store the hot water produced by the boiler. This hot water is then pumped through the central heating system to provide warmth throughout the home.

Heat-only boilers

Heat-only boilers are the traditional type of gas boiler. They require a separate water tank and cylinder to store the hot water produced by the boiler. The hot water is then circulated through the central heating system to provide warmth throughout the home.

How long do gas boilers last?

Gas boilers typically have a lifespan of 10 to 15 years, depending on factors such as usage, maintenance, and the quality of installation. Regular servicing can prolong their lifespan and ensure efficient operation.


Here at Padly, your safety is our priority which is why we've answered some important safety questions that you may have surrounding gas boilers.

Are gas boilers safe?

In short, yes they are. Modern gas boilers have been engineered with advanced technology that is designed to ensure the safety of you, your loved ones and your home. The development of new, innovative safety features such as a sealed or balanced flue have made gas boilers a safe heating solution for homeowners.

However, gas boilers can still pose a risk if they are not installed or maintained by a certified Gas Safe engineer. Furthermore, it is important to have your gas boiler serviced regularly to help identify and address any potential issues, before they become a safety hazard.

What should I do if I smell gas near my boiler?

If you smell gas near your boiler, it is important to act quickly to prevent a potential gas leak. Follow these steps:

  1. Turn off the gas supply to your boiler at the mains.
  2. Open all doors and windows to ventilate the area.
  3. Do not use any electrical switches or appliances, as they could cause a spark and ignite the gas.
  4. Call a Gas Safe registered engineer immediately to check for gas leaks and make any necessary repairs.

Remember, if you suspect a gas leak, it is important to act quickly and seek professional help. Do not attempt to fix the problem yourself, call the gas emergency line on 0800 111 999.


When it comes to gas boilers, efficiency is a key factor to consider. A more efficient boiler means less energy is wasted, resulting in lower energy bills and a reduced carbon footprint.

Are gas boilers energy efficient?

Modern gas boilers, especially condensing ones, are designed to be very energy efficient. They can convert over 90% of their fuel into heat, reducing waste and lowering your energy bills. By choosing a high-efficiency gas boiler, you can save money on your heating costs while also reducing your home's carbon footprint.


When it comes to gas boilers, another important factor to consider is the cost. To give you a rough idea, the cost to fit a combi boiler usually starts at around £1,500. However, this price can vary depending on the brand and model of the boiler you select, as well as the complexity of the installation.

When getting a new gas boiler installed, it's also important to factor in any additional costs, such as installation fees, pipework, and any necessary upgrades to your heating system.

Signs you need a new gas boiler

As a homeowner, it's important to know when it's time to replace your gas boiler. Here are some signs that you may need a new one:

Age of gas boiler: If your gas boiler is over 10 years old, it may be time to consider a replacement. Even if it seems to be functioning properly, older boilers tend to be far less energy-efficient compared to newer models.

Frequent breakdowns: A clear sign you need a new gas boiler is if you find yourself frequently calling out an engineer for repairs. The cumulative cost of these fixes could easily exceed the price of a replacement.

Higher energy bills: If you've noticed that your energy bills are increasing, it can be a strong sign of an inefficient gas boiler. Newer boiler models are designed to meet higher energy efficiency standards, which can help you achieve lower energy bills.

We understand that replacing your gas boiler can be a big investment, but it's important to consider the long-term benefits. A new gas boiler can be more energy-efficient, reliable and safer than an older model. If you're experiencing any of these signs, it may be time to consider a replacement.

Our gas boiler recommendations

If you are considering replacing your gas boiler with a new one, our experts have shared their top recommendations:

Worcester Bosch Greenstar 4000: For an excellent all round gas boiler, our experts recommend the Worcester Bosch Greenstar 4000. This boiler offers exceptional performance, efficiency, and convenience. It is available in both combi and system versions, so it can meet different home requirements. The Greenstar 4000 has earned the Quiet Mark for quiet operation, so it ensures a peaceful home environment and with a standard 5-year guarantee (extendable up to 10 years), you can feel secure in your investment.

Glow-worm Energy: For a reliable and efficient gas boiler, our experts recommend Glow-worm's diverse Energy range. Available in combi, system and regular, there's an option for every household. With advanced features such as high efficiency condensing technology and user-friendly controls, as well as a 10-year warranty, the Glow-worm Energy range ensures comfort, convenience and peace of mind for your household.

Alpha E-Tec: For an excellent budget-friendly gas boiler, our experts recommend the Alpha E-Tec range. This range of gas boilers offers homeowners remarkable budget-friendly heating solutions, that are still able to provide exceptional performance, energy efficiency, and reliability. Choose the Alpha E-Tec range to experience savings on your energy bills as well as peace of mind with Padly's exclusive 10-year warranty offer.

Browse our entire, extensive boiler catalogue here to find the perfect match for your home.

At Padly, our commitment to providing you with the knowledge and guidance you need to make well-informed decisions about your home's heating system is unwavering. Throughout this guide, we have delved into the fundamentals of gas boilers, exploring what they are, the different types available, and how they operate. We've also emphasised the importance of safety when it comes to gas boilers, expressing the need for certified Gas Safe engineers and regular maintenance.

We understand that choosing the right gas boiler for your home or replacing your current one, is a significant decision but, we're here to support you every step of the way. Our certified Gas Safe engineers are on hand to install and maintain your boiler, ensuring its optimal performance and your peace of mind. Get a gas boiler quote today to find the perfect match for your household.