Table of Contents
What is a system boiler?
In today’s UK, the recommendation often leans towards using combi boilers for fulfilling hot water requirements. However, there are instances where system boilers prove to be a more suitable alternative.
To begin, let’s delve into what a system boiler entails and understand its functionality. We’ll also highlight some key factors that make opting for a system boiler the optimal decision in specific scenarios. Don’t hesitate to request a quote for a prompt System Boiler Replacement.
The difference between system boiler and combi boilers
To start, combi boilers serve a dual purpose by providing both hot water and heating for your home through a single unit. They’re ideal for flats or homes with limited space since there’s no need for a separate header tank or hot water cylinder.
However, combi boilers may not be suitable for residences with high hot water demand as they’re designed to supply only one water outlet at a time. This means that when hot water is needed, the boiler switches from heating to supplying hot water, potentially affecting central heating performance. For those situations, consider getting a quote for a System Boiler Replacement promptly.
On the contrary, a System boiler includes a separate cylinder for storing hot water while housing the main heating and hot water system components within the boiler. This setup allows the hot water supply to accommodate multiple taps and showers simultaneously, making it ideal for homes with multiple bathrooms.
The difference between system boiler and regular boilers
The distinction between a system boiler and a conventional boiler (also known as a regular or traditional boiler) can sometimes be subtle, primarily due to the presence of a separate hot water storage cylinder. However, there are key differences.
A conventional boiler typically requires a header tank to draw water from and maintain water levels in the radiator, while a system boiler operates as a sealed system with only a cylinder.
This is why some individuals lean towards choosing a system boiler. However, in certain scenarios, a conventional boiler may be more appropriate for specific household requirements. This is particularly true for homes with low water pressure or older radiator systems that may not be compatible with the higher water pressure of a system boiler.
The Advantages of System Boilers
Abundant Hot Water Supply: System boilers offer the convenience of storing large quantities of hot water for simultaneous use across multiple taps, showers, and radiators.
Harness Solar Energy: By connecting the appropriate cylinder to the system, you can utilize solar panels, promoting eco-friendliness while reducing costs.
Space Efficiency: System boilers require less installation space compared to regular boilers, eliminating the need for expansion tanks or external vessels.
Efficiency and Speed: Equipped with a pump, system boilers deliver rapid responses and boast economical running costs, making them a practical choice.
Important things to consider in System Boiler
There are also some drawbacks to installing a system boiler that you should keep in mind. Here are a few of them:
System boilers need more space than combi boilers
While system boilers are more compact than regular boilers, their requirement for an external cylinder means they still occupy more space compared to combi boilers. This can pose significant challenges, particularly in smaller homes, during the installation process.
Read more: New Boiler Cost
Busier times means more patience
Initially, your cylinder is sized in advance to meet your household’s water needs, typically allowing for around 50 liters of hot water per person. However, during periods of increased usage, such as when hosting extra guests, your hot water supply might deplete. Consequently, you may experience a 30-40 minute wait while your boiler reheats the cylinder to replenish the hot water supply.
Read more: Electric Boilers v Gas Boilers
Finding what you need
In order to find the most suitable boiler for your home and needs you should take the time to compare different models. The question remains as to what to look for and what to compare.
Output Rate: The output rate, measured in kilowatts (kW), indicates the boiler’s power. For regular boilers, this rating specifies how many radiators the unit can effectively heat.
Efficiency: Efficiency refers to how effectively the boiler utilizes the fuel it consumes. Higher efficiency ratings indicate less wasted energy.
Cost Considerations: Explore options that fit within your budget, as prices for regular boilers typically range from £500 to £2,000 (excluding cylinder and installation costs).
Warranty Coverage: Manufacturers provide warranties covering post-installation issues. Each boiler’s warranty differs in coverage and duration.
Heating Controls: Effective heating controls help manage energy consumption, with modern options allowing control via smartphones or tablets.
Customer Reviews: Reading homeowner reviews offers insights into a boiler’s reliability and performance over time, helping you anticipate potential problems before purchase.
Engineer Reviews: Heating engineers possess expert knowledge of boilers and can provide valuable guidance in selecting the right model for your needs. Take the time to consider their recommendations.
Read more: Best Heat Only Boilers
The cost of installation
A lot of factors can impact the cost of installation. These might be:
Accessibility
Installation Complexity
How much rates the installer would charge
Your place of living (for instance, London can be more expensive).
Generally speaking, having a boiler installation might cost you between £800 – £1,500. Here is an idea of how much it might cost you.
Read more: Types Of Reliable Boiler Systems
| Model | Boiler price | Approximate boiler price with installation |
| Baxi 800 | £900 – £1,000 | £1,400 – £2,000 |
| Vaillant ecoTEC Plus | £1,000 – £1,250 | £1,500 – £2,250 |
| Ideal Vogue Max | £1,000 – £1,250 | £1,500 – £2,250 |
| Worcester Bosch Greenstar i | £900 – £1,100 | £1,400 – £2,100 |
| Viessmann Vitodens 200-W | £1,250 – £1,500 | £1,750 – £2,500 |
The right size for you
When discussing boiler size, we’re referring to its power output, measured in kilowatts (kW), not its physical dimensions.
Simply put, a higher output indicates greater power, but opting for the highest output isn’t always ideal. Oversized boilers can lead to increased energy bills, while undersized ones may struggle to meet your demands.
To determine the right output rating, consider factors like the number of bathrooms and radiators in your home. This helps gauge your domestic hot water and central heating needs.
For personalized advice, seek a quote from a Gas Safe registered engineer. Additionally, check manufacturers’ websites for guidance; many offer resources to assist in selecting the right boiler for your requirements.
Here is a table to guide you through what you need to know:
| No. of bathrooms | Radiators | Recommended Output |
| 1 | 10 | 9-15 kW |
| 2-3 | 15 | 18-26 kW |
| 3+ | 20 | 27-40 kW |
To point out, small homes with one bathroom and little or no space for a cylinder should consider getting a combi boiler.
Read about:
Important Tips Before Buying A New Boiler
FAQ’s
Do system boilers run out of hot water?
This factor is determined by the capacity of your hot water cylinder. You should consider how much water you need for taps, baths and showers when choosing the right size. However, you should keep in mind that the size of your cylinder will rely on the space available.
How do system boilers function?
Firstly, a heat exchanger heats the water. Then it moves energy from the gas jets to the water. Once the water is heated, it is moved to the hot water cylinder where it will be stored. Even when you are using multiple taps and showers, a constant supply of hot water is always available.
How much space is required for a system boiler?
There are many things to consider but one of the most crucial points is how much space do you need for a system boiler. In general, a system boiler is larger than a regular boiler so you need to make sure that you have sufficient space. What makes a system boiler bigger is the fact that it has a pump and an expansion tank.