Your guide to system boilers.
What are system boilers?
A system boiler is made up of two parts. The normal boiler you’re used to seeing in your kitchen or air cupboard, and a separate cylinder for storing hot water. This means that system boilers are capable of providing a constant supply of hot water throughout your home, and are commonly found in larger homes which have a greater demand for heating and hot water.
How do system boilers work?
System boilers provide hot water and central heating slightly differently depending on whether they’re a gas-fired system boiler or an electric-powered system boiler.
For gas-fired system boilers which are connected to the mains gas, firstly a flame heats up water in an enclosed hot water system. A coil in the water cylinder carries the central heating water at high temperatures through the cylinder, heating its contents and getting the hot water to where it needs to be.
Electric-powered system boilers work in the same heat but use an electric heat exchanger to warm up the circulated water rather than a gas flame.
This means that the water that comes out from the taps is from the cylinder, rather than the boiler, as it’s constantly being pumped through the coil in the hot water cylinder and the radiator system.
What’s the difference between a system boiler and a combi boiler?
Whilst system boilers have a water storage cylinder which can store hot water for when it’s needed later, combi boilers are a stand-alone heating system and only heat water on demand. This means that combi boilers take up much less space than system boilers, ideal in smaller homes.
Because they don’t store hot water, new combi boilers are suitable for homes with one to three bedrooms and one bathroom as they’ll struggle to meet the needs of a larger household.
System boilers are able to manage the requirements of a large home as they can manage the hot water requirements of multiple radiators, taps and even underfloor heating.
What’s the difference between a system boiler and a regular boiler?
Regular boilers, or heat-only boilers, are similar to system boilers in that they also store hot water for later use. They are often found in large houses, such as four bedroom homes, and come with a header tank, or feed and expansion tank, in the loft.
This header tank in the loft keeps the regular boiler artificially under pressure and also uses an external expansion vessel to maintain the water pressure. System boilers have a pressurised heating circuit and use an internal expansion vessel.
This means that regular boilers often take up more space than a system boiler and can require more complex piping between the water storage tank and boiler. Because of this, system boilers are more commonly installed in modern properties with multiple bathrooms.
What are the advantages of having a system boiler installed?
How much do new system boilers cost?
That depends on a number of factors including:
The size of heating boiler needed to warm your home.
If you need to move your boiler system.
If you’re switching from a different boiler type, such as a combi boiler, or keeping like-for-like.
Any installation costs.
To help you get started, E.ON can give you a quote for having a new boiler installed and recommend the best Worcester Bosch system boiler for your home.
All our boiler installation costs are included in the price for your new boiler.
Are system boilers expensive to run?
System boilers are designed for larger homes and properties, where they’ll be more cost effective than a combi boiler or regular boiler.
The boiler installation costs might be a bit higher, however the aim will be to save money over time as the heating system will be designed to make the use of the water cylinder and ensure you can use multiple hot water points at the same time.
However if you’re in a smaller home then it may be more cost effective to have a combi boiler or regular boiler.
Can I get a new boiler on finance?
Yes, you can pay with interest-free finance rather than paying the full price of your new boiler upfront. You can choose to spread the cost of your Worcester Bosch system boiler flexibly over monthly payments, at no extra cost, with interest-free credit (0% APR) for up to 2 years.
We also have other affordable options to help you finance your new boiler in a way that suits you. We’re a credit broker and not a lender.
Why choose a Worcester Bosch boiler?
What Worcester Bosch Greenstar system boilers do you offer?
We have three Greenstar system boilers currently available. We’ll help you choose the right one for your central heating system:
Greenstar 8000 Life System.
Greenstar 8000 Style System.
Greenstar 4000 System.
What are the disadvantages of a system boiler?
Like any type of boiler, there are several points to bear in mind before you pick a new boiler system:
More space is required for the cylinder.
Busier times (when you have lots of visitors for example) may mean you have to wait for the cylinder to reheat.
May need to add insulation to stop heat and energy loss.
How much space does a system boiler need?
How do I make sure I’ll have enough hot water from my new boiler?
How efficient are new boilers?
^An average household could save up to £540 on their annual gas bill. Savings information for boilers in the UK provided by the Energy Saving Trust, based on a detached house with a boiler rating of G.
E.ON Energy Installation Services Limited acts as a credit broker not a lender and work exclusively with Creation Consumer Finance Limited who acts as the lender. Credit subject to status, terms and conditions apply and can be found at eonenergy.com/terms-and-conditions/eon-installation, E.ON reserves the right to amend its finance offering at any time and may withdraw at short notice. E.ON Next Energy Limited is an Introducer Appointed Representative of E.ON Energy Installation Services Limited who are authorised and regulated by the Financial Conduct Authority in relation to credit broking services under number 750410. Registered in England and Wales under company number 09965944 with its registered office at Westwood Way, Westwood Business Park, Coventry, CV4 8LG.