What Is a Condensing Boiler and How Does It Work?
If your goal is to have a warm, cosy home without high heating bills, an efficient boiler is a must. As part of the complete guide to installing an energy-efficient boiler, this article reveals the inner workings of condensing technology so you can better understand how it keeps your home warm for less. You can also find out about other boiler types in our complete overview.
How Does a Condensing Boiler Work?
Like any boiler, condensing models burn gas or oil to generate heat. Once ignited, the heat is channelled through a primary heat exchanger, where it gets a temperature boost before being distributed to your radiators. In a non-condensing system, the process ends with 200°C exhaust gases releasing into the atmosphere.
However, condensing boilers have a secondary heat exchanger, where warm exhaust air travels through and condenses, forming droplets that are collected and disposed of via a drain. This secondary heat exchanger allows the condensing boiler to recover heat that would otherwise be lost through the flue. The condensing process reduces the temperature of exhaust gases to around 55°C, making it a brilliant method for recycling heat back into your home.
Condensing Boiler Efficiency Rates
Condensing boilers boast excellent ratings, with new models reaching over 90% efficiency. Compare this to non-condensing boilers, which lag behind with ratings no higher than 85% efficiency. This stark difference translates to substantial savings on heating bills and significantly reduced emissions, making condensing boilers cost-effective and eco-friendly.
Are All New Boilers Condensing?
Since 2005, all new gas boilers installed in the UK have been condensing boilers due to a government mandate. The same regulation was applied to oil boilers in 2007. This regulation was intended to combat climate change, as households contribute to around 40% of the UK’s total emissions.
What Are the Advantages of a Condensing Boiler?
The government’s decision to mandate condensing boilers in the UK was not made lightly. While reducing the country’s carbon footprint was the primary goal, individual homeowners benefit in numerous ways as well. Here’s how:
Monetary savings: The impressive energy efficiency rate of over 90% translates to lower energy bills, which add up quickly over time.
Wireless programming: Modern condensing boilers come with wireless thermostats for easy control and automated temperature adjustments.
Space-saving units: These boilers can be tucked away easily without taking up too much space.
Condensing Boiler Pros & Cons
Pros
Higher Energy Efficiency: Condensing boilers are designed to capture heat that would otherwise escape through the flue, leading to energy efficiencies of over 90% and lower energy bills.
Reduced Carbon Emissions: By making more efficient use of the fuel consumed, condensing boilers emit less carbon dioxide than traditional boilers, resulting in a reduced carbon footprint.
Quieter Operation: These boilers tend to operate more quietly, providing a more comfortable environment without the constant noise of older heating systems.
Enhanced Temperature Control: With advanced temperature and heating controls, users enjoy a more consistent and comfortable indoor climate tailored to specific needs.
Cons
Higher Initial Installation Cost: The upfront cost of a condensing boiler can be higher than that of non-condensing counterparts. However, the long-term savings on energy costs can offset this initial investment over time.
Reduced Efficiency in Cold Weather: In extremely cold weather conditions, the efficiency of a condensing boiler can drop as it works harder to maintain heat, though it remains more efficient than traditional boilers overall.
Increased Maintenance and Servicing Needs: The complex systems and technology behind condensing boilers may require more regular maintenance to operate at peak efficiency.
Corrosiveness of Condensate: Condensing boilers produce an acidic condensate due to the cooling of flue gases. This condensate has to be managed properly to prevent corrosion, especially in components made from aluminium, which is particularly susceptible.
Does a Condensing Boiler Need a Water Tank?
The answer depends on what type of condensing boiler you install. There are three to choose from: system boilers, regular boilers and combi boilers. Condensing system boilers and condensing regular boilers require a water tank. However, combi or combination boilers provide heating and hot water directly from the mains without needing a separate cold water tank or external hot water cylinder.
How Long Do Condensing Boilers Last?
The lifespan varies based on build quality, model and usage. With proper annual servicing, you can expect your condensing boiler to last at least 10 years. Check the warranty of any boiler you install to ensure you’re getting a quality product.
How Do I Know If My Boiler Is Condensing?
Identifying whether your boiler is a condensing model is fairly simple. Here’s how:
Consider the installation date: Any boiler installed after April 2005 should be a condensing boiler, as per government regulation.
Examine the flue: Non-condensing boilers typically have a metal flue, while condensing boilers have a plastic flue that goes through an external wall or the roof.
Look at the steam and drainpipe: Condensing boilers produce visible steam from the flue and have a white plastic drain pipe to dispose of the condensate.
Are Condensing Boilers Reliable?
An outdated myth is that condensing boilers are less reliable than their non-condensing counterparts. Modern condensing boilers are engineered to operate smoothly under varying weather conditions, providing consistent heating and hot water. Their superior technology and design ensure fewer breakdowns and longer operational life. In addition, many manufacturers offer extended warranties and support services for your peace of mind.
Are Condensing Boilers Safe?
Condensing boilers are subject to stringent safety checks to ensure suitability for home use. The sealed combustion chamber significantly lowers the risk of carbon monoxide leakage into your home, a common concern with non-sealed boilers. Also, the enclosed system prevents contact with harmful gases. As long as the flue terminates in a safe location and condensation is pumped outside, you can rest assured that you’re investing in a safe home heating system.
What Size Condensing Boiler Do I Need?
Condensing boilers come in different sizes, with heating outputs measured in kilowatts (kW). The size you need depends on your home’s heat and hot water requirements. For example:
A 1- to 2-bedroom home with 0 to 10 radiators and 1 bathroom may need a 24 to 27 kW boiler.
A 3- to 4-bedroom home with 10 or more radiators and 2 to 3 bathrooms may need a 28 to 34 kW boiler.
A 4-bedroom home with 20+ radiators and 3 or more bathrooms may need a 35 to 42 kW boiler.
Always consult a heating professional to accurately determine the boiler size you need based on your household’s requirements.
How Much Do Condensing Boilers Cost?
Depending on the brand and model, a condensing boiler can be between £450 to £2,500. This can pose a financial burden for low-income individuals, vulnerable groups or those on benefits. Thankfully, the UK government has put forth several schemes to alleviate this burden, such as the Energy Company Obligation (ECO) scheme to help eligible individuals afford energy-saving improvements, including condensing boilers. Government-led energy efficiency schemes and other financial aid options are crucial for making condensing boilers accessible to everyone.
Upgrade to a Condensing Boiler Today
MPC Energy Ltd has over 30 years of combined experience in the energy efficiency industry, making us one of the UK’s most trusted condensing boiler installers. Our dedicated and qualified teams have completed thousands of home improvement projects across the UK, providing insulation, heating and renewable installations with top-notch manufacturer products. We also offer free energy and grant advice to guide you in making informed decisions. Contact us today at +44 141 951 7887 for more information or to request a quote for a condensing boiler.
