What is the difference between direct and indirect unvented cylinders?

What’s the Key Difference between Direct and Indirect Unvented Cylinders? – It all comes down to how the water is heated. They’re both sealed systems that draw water straight from the mains supply that facilitates hot water at high pressure, but when it comes to heating those cylinders, it’s left to two very different methods.

Direct Unvented Cylinders

A direct cylinder runs entirely on electricity. They’ve got powerful electric immersion heaters in the tank that produces and stores your hot water. Because of these features, this system is independent of your home’s central heating system, and since it doesn’t have any internal heat exchanger that a boiler needs to connect to, you can install it anywhere. A direct unvented cylinder is a fantastic option if your property is one of those places that can’t get a gas supply, such as an apartment or a remote location. It’s easy to get installed, but keep in mind that electricity is generally pricier than gas; however, you can mitigate the cost difference by heating your water up at night, using cheap-rate electricity or even producing your own electricity via solar PV panels or water or wind turbines for zero-cost electricity. This also means your DHW heating can be carbon emissions-free. Our range of stainless steel direct unvented cylinders is detailed here – Unvented direct cylinders 

Indirect Unvented Cylinders

Now, on the other hand, an indirect cylinder is heated by an external heat source – like your central heating boiler, for example, or maybe solar panels or even a heat pump. It all happens inside the cylinder – an internal heat exchanger, usually in the form of a coiled pipe, that’s located at the bottom of the hot water cylinder. An external boiler heats a separate closed loop of water, and that hot water is then pumped through this coil and into the water you’re drawing from. This way, the two supplies never actually mix. And just as a precaution, most indirect cylinders have a backup electrical immersion heater to keep the water hot if the main boiler were ever to fail. Our range of stainless steel indirect unvented cylinders is detailed here – Indirect unvented cylinders 

In a Nutshell

So basically, a direct cylinder is a straight-up electric-powered-only operation, ideal for homes without a central heating boiler, whereas an indirect cylinder is all about tapping into that external heat source via an internal coil, meaning it’s a more cost-effective option for homes with a standard boiler.