water tank installation in London (26)

Unvented hot water cylinders provide strong, consistent water pressure throughout your home and are a popular choice when upgrading older hot water systems.

If you’re looking to improve flow rates or support multiple bathrooms, you can find a checked unvented hot water cylinder installation service in London with Checkatrade.

Benefits of installing an unvented hot water cylinder

Unvented cylinders provide strong, reliable hot water by drawing directly from the mains. Key benefits include:

• Higher pressure and faster flow to taps and showers
• Suitable for homes with multiple outlets running at once
• No need for a loft cold-water tank, freeing up storage space
• More consistent performance than traditional vented systems

If you'd like to see cost comparisons, read our guide to unvented hot water cylinder costs.

How much does unvented hot water cylinder installation cost in London?

Here are some average estimated costs:

• Unvented hot water cylinder (supply only) – £400-£2,000
• Installation cost – £500–£1,500 depending on system complexity

Some of the most important factors that will affect the cost of an unvented hot water cylinder include:

• Size and capacity of the cylinder
• Whether the system is replacing an existing unvented cylinder or upgrading from a vented setup
• Additional pipework or electrical requirements
• Brand and efficiency rating
• Access to the existing system

You can use our Job Value Estimator for a tailored indication of installation costs. Or read our guide to unvented hot water cylinder costs.

Installation requirements for unvented cylinders

Unvented systems must be installed by a specialist with a G3 qualification due to the safety components involved. A trained installer in London will check:

• Mains pressure and flow rate
• Space available for the cylinder
• Required safety valves and expansion vessels
• Temperature and pressure relief arrangements
• Electrical and discharge pipe requirements

These checks ensure the system meets UK Building Regulations.

Signs you may need a new unvented hot water cylinder

You might consider a replacement or upgrade your hot water cylinder if you notice:

• Poor hot water performance during peak times
• Cylinder age approaching 15–20 years
• Leaks from valves or pipework
• Inconsistent water temperature
• Difficulty maintaining pressure across multiple outlets

A hot water specialist in London can assess whether repair or replacement is the most suitable option.

What should be included in your quote?

When comparing quotes from unvented hot water cylinder installers in London, look for:

• Cylinder capacity and model details
• Labour and material costs
• Any additional electrical or plumbing work
• Disposal of the old cylinder where relevant
• Information on safety components
• Commissioning and system testing

Clear, itemised quotes make it easier to compare options on a like-for-like basis.

Maintaining an unvented hot water cylinder

Unvented cylinders require regular servicing to keep them performing well. Routine checks typically include:

• Inspecting safety valves
• Checking pressure and expansion vessels
• Testing temperature controls
• Looking for any signs of leaks or corrosion

Many manufacturers recommend an annual service to maintain efficiency and extend the lifespan of the system.