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System Boilers: The Complete Guide
Welcome to Master Gas London’s complete system boiler guide. We will cover everything you need to know about system boilers, including their history, effectiveness, advantages, disadvantages, and crucial elements to take into account before making a decision. This guide will give you important information to help you decide if a system boiler is the right choice for you or your property.

System Boiler Offers
Looking for a new system boiler? Master Gas London has got you covered with our latest offer starting from £2320 including installation.
About System Boilers
A system boiler is similar to conventional boiler but eliminates the need for a separate cold water and feed and expansion tank when installed in combination with an unvented cylinder. With a sealed system design, it offers improved energy efficiency and reduced fuel consumption. System boilers provide fast and even heating and work best alongside unvented cylinders. They are a good option for large properties, ensuring ample hot water supply.
Worcester 4000 24kw
£2695
- 10 Year Warranty Included
- Price Includes Materials and Installation
- Hive Mini Smart Thermostat Included
- Worcester Magnetic System Filter Included
- MagnaCleanse System Flush Included
- Disposal of old Boiler and any Tanks Included
Hisory of System Boilers
System boilers have a fascinating history that showcases the evolution of heating technology. In the past, central heating systems relied on gravity-fed hot water systems, which were less efficient and required extensive pipework. However, as demands for efficiency and convenience grew, engineers sought innovative solutions.
The breakthrough came in the late 20th century with the introduction of sealed system boilers. By doing away with the requirement for a separate cold water tank and supplying a more effective heating solution, these boilers revolutionised the sector. By incorporating advanced controls and technology, system boilers improved heating efficiency and reduced fuel consumption.
Vaillant Ecotec Plus 24kw
£2710
- 10 Year Warranty Included
- Price Includes Materials and Installation
- Hive Mini Smart Thermostat Included
- Vaillant Magnetic System Filter Included
- MagnaCleanse System Flush Included
- Disposal of old Boiler and any Tanks Included
Efficiency of System Boilers
Due to their high efficiency, system boilers are a great option for both homes and businesses. The sealed system design minimizes heat loss and ensures consistent hot water availability. Additionally, system boilers often incorporate advanced controls and technology to optimise energy usage and reduce fuel consumption, resulting in lower energy bills.
Baxi 800 24kw
£2185
- 10 Year Warranty Included
- Price Includes Materials and Installation
- Hive Mini Smart Thermostat Included
- Adey Magnetic System Filter Included
- MagnaCleanse System Flush Included
- Disposal of old Boiler and any Tanks Included
Pros of System Boilers
Space Saving
System boilers eliminate the need for a separate cold water and expansion tank, making them a more suitable option than conventional boilers for properties that require a hot water cylinder but have limited space .
Energy-Efficient
System boilers provide rapid hot water delivery and distribute heat evenly throughout your property, ensuring a comfortable living environment.
Hot Water Supply
With a dedicated unvented hot water cylinder, system boilers offer hot water supply at high pressure to multiple outlets simultaneously, accommodating the needs of larger households.
Cons of System Boilers
Higher Upfront Cost
System boilers typically have a higher upfront cost compared to combi boilers as they require a hot water cylinder and external components.
Maintenance Cost
A system boiler will have higher maintenance cost as both the boiler will require servicing and external components are not covered by thw boiler warranty.
Worcester 8000 Life 30kw
£2849
- 12 Year Warranty Included
- Price Includes Materials and Installation
- Hive Mini Smart Thermostat Included
- Worcester Magnetic System Filter Included
- MagnaCleanse System Flush Included
- Disposal of old Boiler and any Tanks Included
Things to Consider
When choosing a system boiler, there are a few other things to consider:
Size: Make sure you choose a system boiler that’s the right size for your home and your hot water needs.
Brand: Choose a reputable brand with a good track record for reliability and performance such as Worcester Bosch, Vaillant or Baxi.
Maintenance: Make sure you have your system boiler serviced regularly to keep it running smoothly and efficiently.
Our Guarantee
At Master Gas London, we take pride in our work and are dedicated to giving our clients the finest support we can. We provide a 12 month guarantee for all of our services, parts and workmanship.
Summary of System Boilers
System boilers offer efficient heating and fast hot water delivery, making them an excellent choice for many homes and businesses. With their design, improved energy efficiency, and convenient hot water supply, system boilers provide reliable heating solutions. However, consider the initial cost and hot water cylinder size before making a decision. Consult a professional heating engineer from Master Gas London for expert advice and installation services tailored to your requirements.
Who are our Engineers?
At Master Gas London, we only employ Gas Safe and G3 qualified engineers. Every engineer is highly experienced with a minimum of 5 years experience. All engineers have undergone thorough vetting to ensure that we only provide the best gas services in the UK.
What Our Customers Say...
FAQ'S
A system boiler is a type of central heating appliance that provides both heating and hot water for your home or business. It works alongside a hot water cylinder, ensuring a constant supply of hot water to multiple outlets simultaneously.
Unlike conventional boilers, system boilers do not require a separate cold water or expansion tank. They have a built-in expansion vessel and operate with a sealed system, which improves efficiency and eliminates the need for a loft or attic space to accommodate a cold water tank.
Yes, system boilers are known for their energy efficiency. The sealed system design minimizes heat loss, ensuring efficient heating and hot water delivery. Additionally, many system boilers incorporate advanced controls and technology to optimise energy usage and reduce fuel consumption.
Yes, system boilers work best alongside unvented cylinders. Unvented cylinders are pressurised, allowing for higher flow rates and more efficient hot water delivery. When combined with a system boiler, they ensure a consistent supply of hot water to multiple outlets simultaneously.
The size of the system boiler required depends on various factors, including the size of your property and your hot water demands. It is best to consult with a heating engineer or professional installer who can assess your needs and recommend the appropriate boiler size.
The installation time for a system boiler can vary depending on the complexity of the project. On average, a system boiler installation can take a day. However, this can be longer depending on the specific circumstances of your property.
Like any heating appliance, system boilers require regular maintenance to ensure optimal performance. It is recommended to have your system boiler serviced annually by a qualified heating engineer. Routine maintenance helps identify and resolve any potential issues before they become major problems.
In many cases, it is possible to replace an existing boiler with a system boiler. However, the feasibility will depend on the specific circumstances of your heating system and property. It is best to consult with a heating engineer or professional installer to determine the compatibility and requirements for a system boiler replacement.