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Reduce your energy bills, never run out of hot water and increase your water pressure.

Why upgrade your old water cylinder to a pressured unvented water cylinder?

Installing a low energy consumption hot water cylinder can significantly reduce your energy bill and improve bath filling times and increase shower pressure. Control your water temperatures to the exact degree with smart controls and 24/7 dayd timers . Heating hot water can account for over 50% of your energy consumption so choosing the right hot water cylinder can save you £100s per year. We offer a range of low energy consumption electric hot water cylinders for your or business.

Our hot water cylinders are incredibly well insulated and have an extremely accurate thermostat which means less temperature variation. Less temperature variation means less energy used. They are also designed to take advantage of economy 7 tariffs & renewable energy sources.

Benefits of pressured unvented water cylinders

  • Much faster heat up time. 
  • Space Saving designs- slimline for narrow airing cupboard and horizontal version for lofts 
  • Super insulation meaning less energy needed to maintain heat.
  • Long guarantee for peace of mind (up to 25 years).
  • Reduced noise levels - pressured system completely silent.

Greenvision can install your water cylinder in one day for a stress-free replacement. Plus we’ll even check you’re on the right tariff for your energy needs to make sure you’re getting the best deal from your energy provider

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Improved Water Pressure

Pressured cylinders free up valuable space in your property and provide stronger water pressure than an old standard cylinder, also known as an open vented system. This is because pressured cylinders are directly supplied by the mains water. Invigorating showers and quick filling baths are achieved.

Space Saving

Pressured hot water cylinders are also perfect space-saving options for your home or business. A pressured hot water cylinder doesn’t require a feeder tanks in the loft and which frees up valuable space in your property. Unlike old cylinders the pressured cylinder doesn’t rely on gravity to function, so it can be installed almost anywhere in your home or business. This makes it easier to store in a place more suitable for you. Greenvision Energy can remodel your airing cupboard to create more space or move your cylinder in to your loft.

Reduced Noise Levels

Other advantages of installing a pressured system include reduced noise levels. No more waking up to cold water filling up the water storage cistern. The pressured system completely silent and sealed, so not at risk of contamination and won’t freeze in winter months.

Other Benefits

  • Much faster heat up time. 
  • Horizontal unvented cylinders available for lofts 
  • Slimline unvented cylinders available for narrow airing cupboards 
  • Super insulation meaning less energy needed to maintain heat. 
  • Stainless steel construction that will eliminate any future rust or corrosion. 
  • Long guarantee for peace of mind (up to 25 years). 
  • A holiday mode setting allowing shut down and restart of up to 30 days.

Book your free survey call 0115 854 7498 or email

Guide to hot water cylinders

If you are considering the purchase of a new hot water cylinder, there are some basic facts that will help you decide which one is right for you. Hot water cylinders are available ‘vented’ and ‘unvented’, and we explain the difference between the two.

Vented hot water cylinders

This type of water cylinder needs a water storage (header) tank to store water piped in from the mains. The tank is usually installed in the loft (or in the highest point in the property) and the system relies on gravity to create a reasonable pressure for the hot water to circulate throughout the property.

Vented cylinders are easier to install than unvented, but they do need a vent pipe to deal with water expansion issues. Households most likely to benefit from vented water cylinders would be properties with an electric shower only, no bath and just one or two people living there.

Unvented (Pressured) hot water cylinders

With this type of cylinder there is no need for a storage tank as water comes straight into the cylinder via the water mains. Mains pressure means gravity feed does not apply, so the cylinder (minus storage tank) can be positioned virtually anywhere at any height, and you get a much more powerful flow than from a vented system. Also, you don’t have to worry about water freezing in a header tank during very cold snaps.

In an unvented installation the system won’t suffer contamination because it is sealed and bypasses areas were impurities could get into the water. With regards to water expansion, the unvented cylinder has either a permanent air bubble infused at the top of the cylinder, or a fitted expansion vessel.

Both vented and unvented hot water cylinders can use either direct or indirect heating systems. With the indirect method the cylinder is heated by a gas boiler or other external source. Hot water passes from the heat source through a copper coil built into the cylinder. In this case it’s a good idea to fit a reserve emersion heater in case of boiler breakdown, so you still have hot water.

The direct method involves one or two heating elements inside the cylinder that heat the water directly. Using the two element option can be very cost effective because it is specifically designed to be used with the Economy 7 tariff - one element for peak day time use and one for off peak where the water is heated cheaply at night and used when needed.

When should I install a new hot water cylinder?

  • If you get constant leaks or breakdowns it could work out cheaper to replace rather than to keep repairing. 
  • Your new boiler will be much more energy efficient and could pay for itself quite quickly. 
  • If you have a big family or use lots of water a new professionally fitted boiler will be sized correctly for your needs, which may not be the case at present. 
  • If you have an old boiler with a red jacket you will be paying higher energy bills than you need to. You would be better off upgrading to a new cylinder and better tariff. The off peak tariff in conjunction with the two element cylinder could save you lots of money. 
  • If your water pressure is low and it takes forever to run a bath or the shower is just a dribble, a new unvented hot water cylinder will give amazing improvements.

Unvented Book your free survey call 0115 854 7498 or email

How do pressured water cylinder work?

In an unvented system there is no cold water tank – instead a sealed hot water cylinder is fed directly by the cold water mains. An unvented cylinder is kept under pressure from incoming water supply and is heated by either immersion heaters (a direct model) or by a heat source located outside the vessel such as a boiler or wet solar system (an indirect model).

Who can install a pressured water cylinder work?

You should only have an unvented hot water system fitted and serviced by a qualified person holding a current G3 Unvented Qualification. All installations of unvented hot water cylinders have to be notified to Building Control as required by Building Regulations. If your installer is a member of a Competent Persons Scheme, this will happen automatically and you will receive a Building Regulation Compliance certificate.

How long do pressured water cylinder last for?

A hot water cylinder should last for more than 20 years if fitted correctly and to the highest standard. However, the life expectancy of a hot water cylinder can be shortened by water leaks.

Where can you install a pressured water cylinder?

They can be installed in almost any location – the garage, upstairs, downstairs, loft or even in a basement. An unvented hot water cylinder needs a safety discharge pipe. Therefore in some basement locations, a sump and pump may be required.

How do I know if I Need pressured water cylinder?

You should consider replacing your hot water cylinder if it is leaking water, but drying at the same time. Leaking water can get worse over time and cause damage. Small leaks can be hard to detect so you should always check for any damp patches surrounding a hot water cylinder. Consult your plumber or call Greenvision Energy if you are unsure about whether your hot water cylinder has a slow water leak.

Why has my old cylinder started to turn green?

Copper corrosion is the cause of the green on your hot water cylinder. The corroding copper is most likely the result of an acid attack of flux or there is water surrounding the area. Copper corrosion may also be the result of a high amount of moisture in the air.

Can I control pressured cylinder using Wi-Fi?

Yes, Greenvision has a range of cylinders that you can control via a smart app.

Unvented Book your free survey call 0115 854 7498 or email


Need a pressured hot water cylinder for apartments


The Benefits

  • Provides mains pressure hot water 
  •  Maximises the benefit of available off-peak electricity tariffs  
  • No annual maintenance or safety check requirement 
  •  Overcomes Part G Building Regulations discharge requirements for unvented cylinders 
  •  No discharge pipework 
  •  Hot water is generated by passing mains cold water through a plate heat exchanger, eliminating any risk of Legionella 
  •  Option to use secondary heat source No G3 qualification requirement for installation

Unvented Book your free survey call 0115 854 7498 or email

Book your free survey

Sit back & relax with our award-winning electric heating installation service

Let us take away the pain & stress of installing your new pressured hot water cylinder

  • Free Survey 
  • Free planning and design service 
  • Free advice on how achieve the best efficient from your new cylinder
  • Installed by an improve manufacture installer.
  • Disposal of your old equipment

Plus we’ll even check you’re on the right tariff for your energy needs to make sure you’re getting the best deal from your energy provider

Call on 0115 854 7498. or email

Reducing energy bills since 2011

With years of experience we work closely with homeowners, tenants, commercial clients, trade partners, and landlords and letting agents to provide everything needed to be more energy efficient, reduce energy bills and also the carbon footprint.

We can help with every aspect of energy efficiency and we’re passionate about offering customers a comprehensive range of the latest products, expert advice, fantastic value and the very highest levels of service.

Need some help or require a quote?

T:- 0115 854 7498   E:-