An unvented hot water cylinder stores hot water directly from the mains water supply. Unlike traditional vented systems that use a cold water tank in the loft, unvented cylinders deliver high-pressure hot water to all your taps and showers. This means you can say goodbye to those weak trickles and enjoy a much more invigorating experience.

Because unvented cylinders are fed directly from the mains water supply, the pressure and flow rate at your taps and showers are generally much stronger than with older, gravity-fed systems. If you’ve been dreaming of powerful showers and baths that fill up faster, an unvented system could be the perfect solution. We always check your incoming mains pressure first to make sure an unvented cylinder is the right choice for your Liverpool home.

The biggest difference is the water pressure. Vented cylinders rely on gravity (the height of your cold water tank), while unvented systems use mains pressure, which is usually much higher. This leads to better flow rates. Also, unvented cylinders don't need a cold water storage tank, freeing up space in your loft. They are sealed systems, which can also improve hygiene as the water isn't stored in an open tank.

Yes, modern unvented cylinders are built to last. Most high-quality options are constructed from robust stainless steel, which offers excellent corrosion resistance and longevity. Brands like Telford and Gledhill, among others, produce excellent stainless steel cylinders that are designed for efficiency and durability.

Good question!

• Direct unvented cylinders heat the water using electric immersion heaters directly inside the cylinder. These are often used in properties without access to a gas boiler, or as a backup.
• Indirect unvented cylinders are more common in homes with a gas boiler. The boiler heats water which then circulates through a coil inside the cylinder, transferring heat to the stored domestic hot water. Some indirect cylinders also have an immersion heater for backup.
  We can help you decide which design is best for your property and heating setup.

The size of the cylinder depends on your household's hot water demand – how many people live there, how many bathrooms you have, and your typical hot water usage (e.g., number of baths and showers). We offer various cylinder options and can calculate the right capacity to make sure you always have enough hot water without wasting energy on an oversized unit.

Absolutely. While vertical cylinders are common, there are also horizontal unvented cylinders designed for properties where space is at a premium, such as in lofts with limited headroom or in airing cupboards. There are various design options to suit different installations, and we can advise on the best fit.

Yes, they do. Because they operate under pressure, unvented hot water cylinders must be installed and serviced annually by a G3 qualified engineer. This is a legal requirement for safety. The annual service involves checking safety devices like the pressure relief valve and expansion vessel, ensuring the cylinder is operating correctly and safely. Our Gas Safe registered engineers at Response Boiler Repair Liverpool are G3 qualified to carry out these essential checks and services.