Hot water cylinders or combi boilers? That’s the question. A new boiler might be one of the most expensive household purchases you’ll make.  It’s important to choose wisely. In this article, you’ll find a brief explanation of the most common ones.

Combi Boiler

Combi, or combination boilers, are the most used type of boiler in the UK. They’re an economical option since combi boilers only heat the water you use.

Why get a new combi boiler?

You get hot water whenever you need it as it heats water straight from the mains.
You need no cold water tank or hot water cylinder – you save space.
They work particularly well if you live in a smaller house or flat.
They’re usually quicker to install because they’ve got fewer boiler parts than other heating systems.

Things to consider

If you use more than one tap at a time, it may divide the flow of hot water.
It depends on the strength of your mains water pressure.
The water might take a few seconds to heat up.


Hot Water Cylinders

Hot water cylinders store hot water for domestic use. Cylinders are heavily insulated and may retain heat many days. Hot water is heated in the cylinder using a coil heated by another source. (A gas boiler or an electric immersion heater within the cylinder itself.)

Hot water cylinders are two main types:

Vented Cylinder

Vented hot water cylinders are fed by cold water from a header tank (normally located in the loft), and they use gravity to drive the hot water around the home. A vent pipe links the vented hot water cylinder and the cold water in the header tank.
The hot water pressure is often influenced by the height of the tank above the tap. On the ground floor, the pressure is excellent – on upper floors, the pressure might be lower. Showers in houses with vented hot water tanks often use electric pumps to drive the hot water to the shower at higher pressure.
They’re cheaper when compared to the unvented system.


Unvented Cylinders

In an unvented system, there is no cold-water tank. The sealed hot water cylinders are fed directly by the cold water mains. They’re operating at mains pressure. It offers much better flow rates, so your shower and bath performance is higher. It has expansion providing hot water flow.
You don’t need to maintain a cold-water tank in the loft (which vented systems require). It frees up space and removes the potential freezing issue during winter.
The unvented cylinder can be located much anywhere as you don’t have to rely on gravity.
There is also reduced noise in the system. Why? There’s no cold water filling of the water storage cistern.
There’s no water storage cistern, and it’s essentially sealed. The cold water is not at risk of contamination.


So… Hot water cylinders or combi boilers?
Feel free to leave us a comment.