If you have a larger family home with multiple bathrooms and high hot water demand, a system boiler could be the ideal heating solution. At Paul Caton Gas Services, we’ve installed hundreds of system boilers, and we’re experts in helping homeowners choose and install the right system for their needs.
What Is a System Boiler?
A system boiler heats water that’s stored in a separate hot water cylinder (tank), while also providing heating to your radiators. Unlike a combi boiler which heats water on demand, a system boiler keeps a tank of hot water ready to use, giving you excellent pressure and flow even when multiple people are using hot water at the same time.
It’s a popular choice for larger homes where you want powerful, consistent hot water throughout the property.
Why Choose a System Boiler?
Excellent Hot Water Pressure Because water is stored and ready, you get strong, consistent pressure from all outlets simultaneously. Multiple people can shower, run baths, and use hot water elsewhere without any drop in pressure or temperature.
Perfect for Larger Homes If you have 3 plus bathrooms or a large family home, a system boiler ensures everyone has hot water when they need it.
Works with Unvented Cylinders System boilers pair beautifully with modern unvented hot water cylinders, giving you mains-pressure hot water throughout your home, a luxury that combi boilers can’t match.
Familiar Technology System boilers use proven, reliable technology that’s been working in UK homes for decades. They’re robust and straightforward to maintain.
Lower Installation Costs Than You Might Think If you already have a hot water tank (or your plumbing is set up for one), installation can be relatively straightforward, often costing less than replacing an entire conventional heating system.
Great for Renewable Energy System boilers integrate beautifully with heat pumps, solar thermal panels, and other renewable heating systems. If you’re thinking green, this is a smart choice.
Flexibility You can upgrade just your boiler without replacing the entire heating system, which often makes it a cost-effective solution.
System vs. Combi Boilers: Which Is Better?
The answer depends on your home and lifestyle.
Choose a System Boiler If:
- You have 2 plus bathrooms with heavy hot water demand
- You want powerful, consistent pressure from all taps and showers
- You have a larger family home
- You’re interested in renewable heating systems
- You like the reliability of proven technology
Choose a Combi Boiler If:
- You have 1-2 bathrooms with lower hot water demand
- You want to save space (no hot water tank needed)
- You prefer lower installation costs
- You like the simplicity of an all-in-one unit
- Your home is smaller
Our Gas Safe engineers will discuss both options during your free survey and recommend what suits your property best.
How a System Boiler Works
Here’s the simple breakdown:
The boiler heats water and sends it to your hot water cylinder (tank), where it’s stored ready to use. When you turn on a hot tap, water flows from the cylinder at mains pressure. The boiler also heats your central heating system on demand.
This two-part approach gives you the best of both worlds: powerful hot water pressure and reliable, efficient heating.
System Boiler Brands We Install
We’re accredited installers for all leading manufacturers:
- Worcester Bosch – Industry-leading reliability and efficiency. Our most popular choice.
- Vaillant – Premium German engineering with exceptional performance.
- Baxi – Reliable and affordable option.
- Ideal Heating – Great value with solid reputation.
Each brand offers models at different price points, so we can find one to suit your budget and home size.
Our System Boiler Installation Process
We handle everything professionally from start to finish.
Step 1: Free Survey We visit your home, assess your heating needs, check your existing hot water cylinder and pipework, and discuss which system boiler would suit you best.
Step 2: Detailed Quote You’ll receive a transparent, itemised quote explaining exactly what’s included, boiler, cylinder (if needed), installation, testing, and commissioning.
Step 3: Expert Installation Our Gas Safe registered engineers will remove your old boiler, install your new system boiler, and connect everything correctly. We can also upgrade your hot water cylinder if needed (like moving to a modern unvented system). Installation typically takes 1-2 working days depending on the scope of work.
Step 4: Full Commissioning We test your system thoroughly, ensure all controls are working, show you how to use everything, and provide all paperwork and safety certificates.
Step 5: Warranty Registration Your boiler is fully registered with the manufacturer, so you get the complete warranty (typically 5-10 years).
Step 6: Ongoing Support After installation, we’re here for annual servicing, and repairs to keep your system running perfectly.
Hot Water Cylinders: Vented vs. Unvented
With a system boiler, you’ll also consider what type of hot water cylinder to use.
Vented Cylinders (traditional)
- Require a cold water tank in the loft
- Lower pressure (gravity-fed)
- Older technology
- Lower upfront cost
Unvented Cylinders (modern)
- No tank needed in the loft
- Mains pressure hot water throughout your home
- More efficient
- Works beautifully with heat pumps and renewable energy
- Higher upfront cost but better long-term benefits
We recommend unvented cylinders for most larger homes, as they give you the best performance and work brilliantly with modern heating systems.
Cost of System Boiler Installation
System boiler installation costs depend on:
- Which brand and model you choose
- Your existing pipework condition
- Whether you need a new hot water cylinder
- If you’re upgrading from vented to unvented cylinder
- Any additional work required
For a new boiler alone, expect £1,500–£3,500+. If you’re also upgrading your hot water cylinder to an unvented system, add £1,500–£2,500+.
We offer 0% interest finance options from 2 to 10 years, making it affordable to upgrade.
Frequently Asked Questions
How long does installation take? Usually 1-2 working days. We’ll give you an exact timeframe after our survey.
Do I need a new hot water cylinder? Not necessarily. If your existing cylinder is in good condition, we can work with it. However, upgrading to a modern unvented cylinder gives you better pressure and efficiency.
What warranty do I get? Typically 5-10 years on the boiler depending on the brand and model. Cylinders usually have 7-10 year warranties. We’ll explain all options.
Can I install a system boiler if I currently have a combi? Yes. We’d need to fit a hot water cylinder, but this is straightforward. Our survey will confirm exactly what’s involved.
How does a system boiler save money compared to a combi? System boilers aren’t necessarily cheaper to run than combis. The savings come from avoiding pressure issues in larger homes (you don’t waste water waiting for hot water to arrive) and from integrating with renewable energy systems.
Will a new system boiler reduce my energy bills? If your current boiler is old, a modern A-rated system boiler will reduce bills by 20-30%. The real savings come when combined with a heat pump or solar thermal system.
Is a system boiler more reliable than a combi? Both are equally reliable. System boilers use simpler, proven technology, but modern combis are just as dependable. Choose based on your home’s needs, not reliability.
How often should I service my system boiler? Annual servicing is recommended to maintain efficiency and keep your warranty valid. We can arrange this for you.
Why Homeowners Choose Us
With over 25 years’ experience installing system boilers, our Gas Safe engineers know these systems inside out. We’re not just installers, we’re advisors who help you make the best choice for your home. Our customers love our friendly service, transparent pricing, and professional workmanship. Much of our work comes through word of mouth recommendations.
We serve customers throughout Bolsover, Shirebrook, Tibshelf, South Normanton, Clay Cross, Chesterfield, Derbyshire, Nottinghamshire and surrounding areas, from Worksop to Ripley, Mansfield to Newark.
Ready to Install a System Boiler?
Get a free, no-obligation quote today. Our friendly engineers will assess your home, discuss your hot water needs, and recommend the perfect system for you.
Call 01246 854 668 or 07976 839 052
Or request a callback and we’ll be in touch within 24 hours.
Paul Caton Gas Services – Over 25 years of expert system boiler installation.