- Content Guide
- » What is a Condensing Boiler?
- - How Does a Condensing Boiler Work?
- - Do Condensing Boilers Need a Drain?
- » What Is a Combi Boiler?
- - How Does a Combi Boiler Work?
- » What's the Difference Between a Combi Boiler and a Condensing Boiler?
- » Benefits of a Condensing Boiler
- » Best Temperature Settings for a Condensing Boiler
- » How Much Do Condensing Boilers Cost?
- » What Size Condensing Boiler Do You Need?
- » Comparison of Leading Boiler Models
- » Is It Time to Upgrade to a Condensing Boiler?
Heating your home efficiently is one of the most crucial considerations for homeowners and HVAC professionals alike. With high energy costs and an increasing focus on sustainability, condensing boilers have emerged as the most efficient and eco-friendly heating solutions available today.
But what is a condensing boiler, and how does it differ from other boiler types? This blog will break it all down for you, covering how condensing boilers work, their benefits, the best temperature settings, and how to choose the right size and type for your home or project.
What is a Condensing Boiler?
A condensing boiler is a high-efficiency heating system that runs on gas or oil.
The design is built to capture and reuse heat that would otherwise be lost through the flue in older, non-condensing boilers.
By cooling exhaust gases until they condense into water vapour, condensing boilers capture and reuse this heat to improve energy efficiency.
Modern condensing boilers can achieve energy efficiency ratings of over 90%, making them significantly more effective than non-condensing models.
If you're thinking about getting a new boiler installation done, knowing these differences can guide you in making a well-informed choice!
How Does a Condensing Boiler Work?
A condensing boiler operates by extracting heat from the flue gases. Then, use it to preheat the water before it enters the boiler.
The system burns gas or oil to create heat, which enters the primary heat exchanger and gets transferred to the water supply.
Flue Gases Enter the Secondary Heat ExchangerUnlike traditional boilers, condensing boilers feature a secondary heat exchanger. This component extracts additional heat from the flue gases, cooling them down to around 55°C, compared to the 200°C typical of non-condensing boilers.
Condensation FormationThe cooling process causes water vapour in the exhaust gases to condense, releasing latent heat. This heat is recycled, boosting efficiency.
Drainage of CondensateThe condensed water, or condensate, is removed through a drainpipe connected to the boiler. This dual-stage process ensures less heat is lost, and more energy goes directly into heating your home.
Do Condensing Boilers Need a Drain?
Yes, they do! All modern condensing boilers require a drain to dispose of waste condensation. This drain works alongside the external flue, which releases waste gases as steam. It's a vital part of how these boilers operate efficiently.
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What Is a Combi Boiler?
A combi boiler, short for a combination boiler, is a smart all-in-one system that takes care of your home's heating and hot water needs.
How Does a Combi Boiler Work?
Traditional boilers rely on a cold water tank (often found in the attic) to feed water into the system. The boiler heats the water, which is then stored in a hot water cylinder until you need it.
Combi boilers work differently. They take cold water directly from the mains and heat it instantly whenever you turn on a tap or shower.
There's no need for a hot water cylinder, so you save space in your home. Plus, you'll always have hot water on demand without worrying about running out, unlike with traditional boilers.
What's the Difference Between a Combi Boiler and a Condensing Boiler?
First, let's clarify: all combi boilers made today are also condensing boilers, but not all condensing boilers are combi boilers.
Confusing? Let's break it down.
This means you don't have to decide between a combi boiler and a conventional one based on energy efficiency—every combi boiler is a condensing boiler!
Combi Boiler:"Combi" stands for combination. These boilers combine heating and hot water in one unit, so there's no need for a separate tank or cylinder. They're perfect for small homes with one or two bathrooms and are quick and easy to install.
Condensing Boiler:Condensing boilers are designed with a secondary heat exchanger, which makes them much more energy-efficient than standard (or "heat-only") boilers.
System Boiler:System boilers are perfect for homes of all sizes, especially those with higher heating and hot water demands.
They store hot water in a cylinder, allowing multiple taps or showers to run simultaneously without losing pressure. However, you'll need enough space, like an airing cupboard or utility room, to house the cylinder.
Regular Boiler:Regular boilers are ideal for medium to large homes with high hot water needs, as they can supply multiple taps or showers simultaneously without losing pressure. However, you'll need space for a hot water cylinder (like in an airing cupboard) and a cold water tank in the loft.
Here's how they compare to standard boilers:
- Efficiency: Condensing boilers recover more heat from waste gases, while standard boilers release these gases at a much higher temperature (over 200°C!).
- Technology: Condensing boilers have advanced heat exchangers that retain more heat, making them eco-friendly and cost-effective.
Benefits of a Condensing Boiler
There are several reasons to install a condensing boiler in your home:
- High Efficiency
With energy efficiency ratings exceeding 90%, condensing boilers reduce energy waste, making them cost-effective and eco-friendly. - Lower Energy Bills
By recycling heat, condensing boilers use less fuel, helping you save money on energy bills. - Environmentally Friendly
Their reduced carbon footprint means condensing boilers align with efforts to combat climate change. - Space-Saving Designs
Condensing boilers, such as the Worcester Bosch Greenstar 30i ERP Condensing Combi Boiler, are designed to be compact, making them suitable for fitting into tight spaces. - Safe and Reliable
Condensing boilers are sealed systems, reducing the possibility of leaks and exposure to harmful substances.
Best Temperature Settings for a Condensing Boiler
To maximise efficiency, your condensing boiler should be set to the correct temperature:
Central Heating | Hot Water |
---|---|
The ideal flow temperature is around 70°C. | Your hot water should be set to 60°C. |
How Much Do Condensing Boilers Cost?
The cost of a condensing boiler varies depending on the brand, type, and installation.
Here's a breakdown:
- Entry-Level Models
Starts at around £1,000 for simple combi boilers. - Premium Options
High-end models, such as the Viessmann Vitodens 100-W, can cost upwards of £2,500, excluding installation. - Installation Costs
The cost of a boiler installation typically ranges from £500 to £1,500, depending on the job complexity and location.
Explore our blog: Things to Consider Before Installing a Boiler!
What Size Condensing Boiler Do You Need?
Choosing the right boiler size is critical to ensure it meets your home's heating and hot water demands. Boiler size is measured in kilowatts (kW), indicating its output capacity.
Small Homes | 1-2 bedrooms, 1 bathroom | A 24–27 kW combi boiler is usually sufficient. |
Medium Homes | 3-4 bedrooms, 1-2 bathrooms | A 28–34 kW combi boiler would suit this setup. |
Large Homes | 4+ bedrooms, 2+ bathrooms | A 35–42 kW boiler might be needed for sufficient heating and hot water supply. System boilers or conventional boilers may also be better suited for larger properties with higher demand. |
If you're unsure, consult a heating engineer to assess your specific requirements.
Comparison of Leading Boiler Models
You can't go wrong with reputable brands when considering a condensing boiler.
Brand | Model | Energy Efficiency | Key Features | Environmental Impact |
---|---|---|---|---|
Vaillant | ecoTEC Plus | A-rated | Quiet operation, eco-friendly | Reduced carbon emissions |
Viessmann | Vitodens 100-W | A-rated | Compact design, smart controls | Advanced low-emission technology |
Alpha | E-Tec Plus | High efficiency | Compact, cost-effective | Energy-saving performance |
Ideal | Logic Plus | A-rated | Easy installation, user-friendly | Optimised energy efficiency |
Worcester Bosch | Greenstar i | A-rated | Durable build, smart controls | Environmentally conscious design |
Is It Time to Upgrade to a Condensing Boiler?
Switching to a condensing boiler is a smart choice for anyone looking to upgrade from an old or inefficient system. Not only will you benefit from low energy bills, you'll also make a positive impact on the environment.
Whether you're a homeowner considering an upgrade or an HVAC professional recommending the right system for a client, condensing boilers are the clear choice for efficiency, reliability, and sustainability.
Need help finding the perfect boiler?
Get in touch with Serviceteam's experts for personalised heating services and professional installation.