Cylinders & Kits | Plumbing Supplies

Discover our range of hot water cylinders and cylinder kits, designed to provide reliable hot water storage for modern heating systems. Whether you're replacing an existing cylinder, upgrading your hot water system or completing a new installation, our collection includes high-quality unvented cylinders, indirect cylinders, direct cylinders and complete cylinder kits from trusted manufacturers.

At JJ Building Materials, we stock a carefully selected range of unvented hot water cylinders, stainless steel cylinders, hot water storage cylinders and complete cylinder packages from leading brands including Vaillant, Everflo, Ideal Heating and Onyx. Available in a variety of capacities and specifications, our cylinders are designed to deliver excellent hot water performance while helping maximise system efficiency.

Whether you're installing a new boiler, upgrading a heating system or replacing an ageing cylinder, our range offers dependable solutions suitable for family homes, new build developments and renovation projects. Modern hot water cylinders are highly insulated, helping reduce heat loss and maintain hot water temperatures for longer periods.

What Is a Hot Water Cylinder?

A hot water cylinder stores heated water ready for use throughout the home. Unlike combi boiler systems that heat water on demand, cylinder systems store hot water so it can be supplied to multiple taps, showers and bathrooms simultaneously. This makes them particularly suitable for larger households and homes with higher hot water requirements.

Hot water cylinders are commonly used with system boilers, regular boilers and renewable heating systems, helping provide consistent hot water performance throughout the property.

Our Cylinder & Kit Range

Unvented Hot Water Cylinders

Unvented cylinders are one of the most popular choices for modern homes. Connected directly to the mains water supply, they provide strong water pressure and excellent hot water performance throughout the property. They are ideal for homes with multiple bathrooms and higher hot water demand.

Direct Hot Water Cylinders

Direct cylinders heat water using immersion heaters installed within the cylinder itself. They are often used where no external heat source is available or where electric water heating is preferred.

Indirect Hot Water Cylinders

Indirect cylinders heat water via a coil connected to a boiler or heating system. They are one of the most common cylinder types found in UK homes and offer efficient integration with central heating systems.

Cylinder Kits

Cylinder kits provide a complete package containing the essential components required for installation. Purchasing a cylinder and kit together can simplify installation while ensuring compatibility between components.

Heat Pump Cylinders

Heat pump cylinders are specifically designed to work efficiently with renewable heating technologies, helping maximise system performance and energy efficiency.

Why Choose a Hot Water Cylinder?

Hot water cylinders remain one of the most effective solutions for homes with higher hot water demand.

Benefits include:

• Excellent hot water storage capacity
• Strong hot water pressure
• Suitable for multiple bathrooms
• Reliable hot water supply
• Compatible with system boilers
• Compatible with regular boilers
• Suitable for renewable heating systems
• Energy-efficient insulation
• Long-lasting performance
• Available in a range of capacities

Who Are Hot Water Cylinders Suitable For?

Homes With Multiple Bathrooms

Hot water cylinders allow multiple showers, taps and bathrooms to be used simultaneously without significantly affecting performance.

Family Homes

Properties with higher daily hot water demand often benefit from the stored hot water capacity offered by a cylinder system.

System Boiler Installations

Most system boilers are designed to work alongside a hot water cylinder, providing reliable heating and hot water throughout the property.

Regular Boiler Systems

Traditional heating systems commonly utilise hot water cylinders to store and distribute hot water efficiently.

Renewable Heating Systems

Heat pumps and renewable energy systems often rely on specially designed cylinders to maximise efficiency and performance.

Unvented vs Vented Hot Water Cylinders

Unvented Cylinders

• Connected directly to the mains water supply
• Strong water pressure
• No cold water storage tank required
• Ideal for modern homes
• Suitable for multiple bathrooms

Vented Cylinders

• Work alongside a cold water storage tank
• Common in older heating systems
• Lower installation costs in some applications
• Traditional system design

For most modern homes, unvented cylinders are often preferred due to their excellent water pressure and space-saving benefits.

Choosing The Right Cylinder Size

Selecting the correct cylinder size is important to ensure sufficient hot water capacity.

120–180 Litre Cylinders

Often suitable for apartments, smaller homes and households with lower hot water demand.

180–250 Litre Cylinders

A popular choice for average family homes with one or two bathrooms.

250–300 Litre Cylinders

Ideal for larger homes with multiple bathrooms and higher daily hot water usage.

The correct cylinder size will depend on the number of occupants, bathrooms and daily hot water requirements.

Popular Cylinder Brands

We stock hot water cylinders from trusted manufacturers, including:

• Vaillant Cylinders
• Everflo Cylinders
• Ideal Heating Cylinders
• Onyx Cylinders

These brands are recognised for their quality, efficiency and reliability.

Why Upgrade Your Hot Water Cylinder?

Replacing an older cylinder with a modern insulated model can offer significant benefits:

• Improved hot water retention
• Reduced heat loss
• Better energy efficiency
• Improved hot water pressure
• Greater reliability
• Lower running costs
• Enhanced compatibility with modern heating systems

Modern cylinders feature advanced insulation technology that helps keep water hotter for longer while reducing energy consumption.

Benefits of Hot Water Cylinders & Kits

• Reliable hot water storage
• Excellent hot water pressure
• Suitable for multiple bathrooms
• Available in direct and indirect models
• Compatible with system and regular boilers
• Suitable for renewable heating systems
• Highly insulated designs
• Stainless steel construction options
• Long service life
• Fast UK delivery

Why Choose JJ Building Materials?

At JJ Building Materials, we supply high-quality plumbing and heating products from trusted manufacturers at competitive prices. Whether you're replacing a hot water cylinder, installing a new heating system or sourcing products for a large-scale project, our range offers reliable solutions backed by expert support and fast UK delivery.

Frequently Asked Questions

What is a hot water cylinder?

A hot water cylinder stores heated water ready for use throughout the home, providing a reliable supply of hot water to taps, showers and bathrooms.

What is an unvented hot water cylinder?

An unvented cylinder is connected directly to the mains water supply and provides strong water pressure without requiring a cold water storage tank.

What's the difference between a direct and indirect cylinder?

A direct cylinder uses immersion heaters to heat water, while an indirect cylinder uses a coil connected to a boiler or heating system.

Are unvented cylinders better than vented cylinders?

For many modern homes, unvented cylinders provide better water pressure and eliminate the need for a loft tank, making them a popular choice.

What size hot water cylinder do I need?

The correct size depends on the number of occupants, bathrooms and your household's daily hot water usage.

Can a hot water cylinder supply multiple bathrooms?

Yes. Correctly sized cylinders are designed to provide hot water to multiple bathrooms simultaneously.

Are hot water cylinders energy efficient?

Modern cylinders feature high levels of insulation, helping minimise heat loss and improve energy efficiency.

How long does a hot water cylinder last?

A quality hot water cylinder can often provide 15–25 years of reliable service when correctly installed and maintained.

Do unvented cylinders need special installation?

Yes. Unvented cylinders must be installed in accordance with UK regulations by a suitably qualified installer.

Can hot water cylinders be used with heat pumps?

Yes. Many modern cylinders are specifically designed for use with heat pumps and renewable heating systems.

What is included in a cylinder kit?

Cylinder kits typically include essential installation and safety components required for a compliant installation.

Why are stainless steel cylinders popular?

Stainless steel cylinders offer excellent durability, corrosion resistance and long-term reliability.

Are hot water cylinders suitable for family homes?

Yes. Hot water cylinders are particularly well suited to family homes with higher hot water demand and multiple bathrooms.

Can I replace my existing cylinder with a larger one?

In many cases, yes. However, the suitability of a larger cylinder will depend on the available installation space and system requirements.

Why buy hot water cylinders and kits from JJ Building Materials?

We offer a carefully selected range of cylinders and kits from trusted manufacturers, backed by competitive pricing, expert support and fast UK delivery, helping you find the right hot water solution for your home or project.