Unvented Cylinders vs. Vented Cylinders and Combi Boilers

We’ll start with traditional vented cylinders. These must be installed at the top of the home, as the hot water is gravity fed. That immediately means two things. First, you won’t have great pressure at the taps, and you’re going to sacrifice attic space to install the water cylinder.

Vented cylinders are also exposed to the outside air, which makes them more susceptible to threats like mould and bacteria. Once those invade your cylinder, it can be very difficult to eradicate them.

Combi boilers are popular with some UK residents who have smaller properties. It allows you to remove the water tank and vented cylinder in the attic and instead install a combi boiler that provides all-in-one heating for your washing up, as well as for warming your home. However, these systems have their drawbacks. They’re really only designed for smaller setups, so if you have more than 10 radiators and more than one bathroom, you’ll want to consider something else.

Unvented offer the flexibility that vented cylinders don’t and the ability to supply hot water to multiple bathrooms that combi boilers don’t. These are sealed, pressurised systems and they can offer a host of advantages over the other options on the market, including:

• Mains pressure hot water at every tap in the home
• No need to take up attic space as they can be installed anywhere in the home
• Less risk of mould/bacteria because the cylinder is sealed
• Less risk of frozen pipes during the winter since there is no need for tanks or pipes in the attic
• Does not create a gurgling sound like vented cylinders
• Can supply water for more than 10 radiators and multiple bathrooms
• Unvented cylinders can usually be combined with solar panels to reduce energy consumption

However, there are a few drawbacks to consider with unvented cylinders. For instance, if the mains water is off, you’ll have no hot water in the home. There’s also the fact that your unvented cylinder must be professionally serviced every year. Failure to do this could void your home insurance. Finally, only G3 qualified plumbers can install unvented cylinders.