young heating engineer

With the prevailing climate changes, it is known that winters are more severe and so are the summers. In such a scenario, hot water cylinders are not a luxury but work out to be a necessity. These hot water cylinders are for storing warm water and, also in heating systems that are gravity-based and mains-pressure. There are two types of cylinders,

  • Direct and
  • Indirect

Most of the hot water cylinders are heated through a heat source that is external, like the solar thermal or the gas boiler.

Functionally, this is very much like the electric jug. Hot water cylinder uses an element and a thermostat for heating the water in the tank to a specific temperature. As you keep on using the water in the cylinder, this is replaced by cold water. This triggers the thermostat and activates the element, heating the water.

Types of Hot Water Cylinder

You can choose from 4 different types of hot water cylinders.

  1. Direct hot water cylinders
  2. Indirect Hot water Cylinders
  3. Vented hot water cylinders
  4. Unvented Hot water cylinders.

Direct Hot Water Cylinders

The direct cylinders are designed specifically with the immersion heaters within the given cylinder. This heats the water directly. Some of the cylinders make use of multiple water heaters for keeping the water warm, and offer maximum performance.

Indirect Hot Water Cylinders

These hot water cylinders need an external source for heating. This is, most often, the boiler. These indirect systems can also be fitted with a back-up heater, that is, the immersion heater. This can also be used for boosting the functions.

Vented Hot Water Cylinders

The vented cylinders are those cylinders that are connected to any cold water tank. The water supply for these is not from the main source but from the tanks.

Unvented Hot Water Cylinders

These cylinders are connected to the main water supply source. There is no requirement of any tank. These tanks can be installed anywhere in the house as these do not depend on gravity but depend on pressure.

Tips on Choosing Hot Water Cylinders

Before investing in any hot water cylinder, it is advisable to follow the listed tips. This can ensure that you make the right choice of the hot water cylinder.

Check the Size of the Household

As there are different sizes of hot water cylinders available in the market, it is important to determine the number of people who will be using this. You can select accordingly. At an average, a single individual uses 50L of hot water. This might increase if other chores are also done with warm water. This includes washing clothes and the vessels.

This can be calculated with the help of a supplier of hot water systems.

Identify the Hot Water System

There are five criteria before you make a choice of hot water systems. This includes continuous flow or storage, method of heating, cost, and size and energy efficiency.

All these factors have an impact on the cost of utility and use of energy.

Methods of Heating

A hot water system can run on natural gas, electricity or even solar energy. Each of these methods has their own set of benefits.

For example, a system that runs on electricity can be affordable for installing and affordable, but the cost of running is quite high.

Continuous Flow or Storage

There are quite a few hot water systems that instantly heat water, while the others use storage tanks.


The hot water needs of a home can determine the exact size of the hot water tank. This cannot be too large as it gets difficult to maintain water temperature to the optimal. A size that is too small can also be problematic.


It is important to consider the annual operating and maintenance costs before making a choice of any hot water cylinder. Heaters with tanks that are not insulated right tend to waste energy. Each model of hot water systems has different factor of energy. This is based on standby losses, efficiency of efficiency, and the cycling losses.

Insulation of Hot Water Cylinders

The best way to save on energy and money is to ensure that the hot water cylinder is well insulated. This not only speeds up the process of heating but also can maintain the temperature of operating. Insulation helps in preventing the escape of heat. This makes it cheaper to use and also, reduces the heat that escapes.

You need to be aware that a good quality water heater can last for almost 8 to 12 years.  This can even last longer if you make an effort and maintain this well. This is then replaced. The size of a household is essential for determining the right size of the water heater.

A broken dip tube, a buildup of sediment and a heating element that is faulty can be the cause of the supply of hot water running out fast.