How To Tell If A Boiler Is Condensing Or Not

Boilers play an important role in maintaining a warm and comfortable home, especially during the colder months.

Understanding the type of boiler you have can significantly impact both your energy efficiency and heating bills.

Here’s a guide to help you figure out whether your boiler is condensing or non-condensing, along with the benefits of each type.

What Is A Condensing Boiler?

A condensing boiler is a highly efficient heating system that reuses the heat from the gas produced during combustion.

Unlike non-condensing boilers, which can lose up to 40% of their heat through the flue, condensing boilers recover most of this heat, thereby improving efficiency significantly. This process not only reduces carbon emissions but also lowers energy bills.

Condensing boilers can run on either gas or oil and are by far the most common type of boiler found in homes across the UK.

One of the main reasons for their prevalence is the legal requirement since April 2005 for all newly installed gas-fired boilers to be condensing models. A similar requirement has applied to oil-fired boilers since 2007.

How Does A Condensing Boiler Work?

To understand a condensing boiler’s efficiency, it’s helpful to compare it with a non-condensing boiler.

In any central heating system, hot water flows out to the radiators and returns to the boiler. A non-condensing system typically heats water to 80°C, and as the water circulates through the radiators, it cools to around 60°C before returning to the boiler.

A condensing boiler operates at lower temperatures. For it to condense, the return water temperature needs to be below 54°C. When the temperature drops to this level, the water vapour in the boiler’s exhaust gas condenses back into liquid, releasing additional heat.

This extra heat boosts the boiler’s efficiency, potentially reaching over 90% if the return water temperature is around 45°C.

The process is called condensing because the heat needs to turn back into water before it leaves the flue via the secondary heat exchanger.

When the temperature of the water returning to the boiler is less than 54°C, the boiler runs in what is known as ‘condensing mode’. This is when the boiler starts to recover its lost heat.

Even this is a sliding scale; at 54°C, the boiler is 87% efficient in perfect testing conditions. The boiler does not reach 90%+ efficiencies until the return temperatures are around 45°C.

This means water must exit the boiler at a maximum of 65°C, impart 20°C of heat to the room via the radiators, and return at 45°C. This makes radiator balancing very important to ensure enough heat is given off to the room to lower the return temperature sufficiently.

To source spare parts for boilers visit Trade Parts Finder today.

What Makes A Boiler Condensing?

The distinguishing feature of a condensing boiler is its ability to recover and reuse otherwise lost heat. This process involves a secondary heat exchanger that captures the heat from the condensing vapour.

In simple terms, a condensing boiler not only uses the heat generated from burning fuel but also extracts additional heat from the condensation process.

Since very few boilers last 17+ years, you can see why condensing boilers largely rule the roost when it comes to household boilers nationwide.

This technology makes condensing boilers much more efficient than their non-condensing counterparts, making them a popular choice for homes across the UK.

How Can I Tell If I Have A Condensing Boiler?

Identifying whether your boiler is condensing can be straightforward if you know when it was installed. Here are some practical steps to determine if your boiler is condensing:

1. Check the Installation Date: If your boiler was installed after April 2005 (for gas boilers) or after 2007 (for oil boilers), it is likely a condensing model due to legal requirements. These dates mark the point when it became mandatory for new boilers to meet higher efficiency standards.
2. Look at the Flue: Condensing boilers typically have a white plastic flue, whereas non-condensing boilers have a metal flue. This is because condensing boilers need to handle the acidic condensate produced during operation, and a plastic flue is better suited for this purpose.
3. Examine the Drainpipe: A key indicator of a condensing boiler is the presence of a white plastic pipe leading to a drain. This pipe carries away the condensate produced during the condensing process. If you have a plastic pipe running to a drain outside your home, it’s a strong indication that you have a condensing boiler.
4. Observe for Steam: During operation, if you see steam coming from the flue, it is another sign that you have a condensing boiler. This steam is a by-product of the condensing process, which releases heat as the water vapour condenses back into liquid.

Conclusion

Determining whether your boiler is condensing or not is crucial for understanding its efficiency and potential cost savings. Condensing boilers are designed to be more efficient by capturing and reusing heat that would otherwise be lost. By checking the installation date, examining the flue and drainpipe, and observing for steam, you can easily identify if you have a condensing boiler.

This knowledge not only helps in maintaining your heating system but also ensures you’re making the most of your energy usage, ultimately reducing your carbon footprint and saving on heating bills. If you discover that your boiler is not condensing, it might be worth considering an upgrade to take advantage of the improved efficiency and cost savings offered by modern condensing boilers.

To source spare parts for boilers visit Trade Parts Finder today.