Direct or Indirect Hot Water Cylinders
Direct or Indirect hot water cylinders relates to the way in which the cold water is heated inside the copper cylinder.
What is a Direct Hot Water Cylinder?
A direct hot water cylinder uses heat sources physically located in the cylinder, such as an electric immersion heater, to heat the water.
These plumbing heating systems tend to be located in premises where there is no access to gas, particularly upper level flats or apartments.
On occasion a direct hot water cylinder will feature two immersion heaters which will enable you to take advantage of off-peak energy tariffs and therefore minimise the overall running costs.
Check out our POWERflow Unvented Cylinder range or our wide range of standard Open Vented Direct Cylinders.
Direct cylinders have continued to advance over the years and leading manufacturer McDonald Water Storage now offer a choice of thermal stores, with MULTIflow providing mains pressure hot water, or the ELECTRAflow and ELECTRAstore, which can provide both hot water and heating using electric immersions all from one simple to use unit.

What is an Indirect Hot Water Cylinder?
An indirect hot water cylinder typically uses an external energy source, such as a traditional central heating boiler or a solar thermal system, which is fed into the cylinder via a coil or heat exchanger which then ‘indirectly’ heats the hot water.
Many indirect hot water cylinders also come with an electric immersion heater to act as a back-up should the primary energy source fail or be unavailable.
A direct or indirect hot water cylinder can be incorporated into vented and unvented cylinders depending on your project requirements.
For Unvented Indirect Hot Water Cylinders, check out our POWERflow Unvented Cylinders range or click here to view our range and price of Open Vented Indirect Hot Water Cylinders.

McDonald Water Storage Direct and Indirect Hot Water Cylinders
Can we help? If you have any hot water cylinder requirements, we would be delighted to help. Simply contact us today online or talk to one of our technical sales team on 01592 611123.
POWERflow: Direct and Indirect Hot Water Cylinders from McDonald Water Storage – Ireland and UK wide distribution.
Frequently Asked Questions
A hot water cylinder is a type of water storage tank used to store hot water for use in various applications. It is typically made from copper or stainless steel and is designed to hold a certain amount of hot water.
The cylinder utilises either an electric immersion heater directly fitted to the cylinder or gas boiler, indirectly heating the cylinder via an internal coil.
A direct hot water cylinder is an efficient and cost-effective way to provide hot water for your home. A direct hot water cylinder is a type of water heater that heats water directly from the mains supply, without the need for a separate boiler or other heating system.
The main benefit of a direct hot water cylinder is that it is energy efficient.
A direct hot water cylinder is a type of water heater that uses a direct heat source to heat water stored in a tank.
The heat source is an electric element, with the water stored in the cylinder being heated by the direct heat source and then circulated through pipes to the various taps and showers in the home.
The maximum temperature and pressure for a hot water cylinder will depend on the type of cylinder, as well as the type of fuel being used to heat the water.
Generally speaking, the maximum temperature for a hot water cylinder is around 60°C (140°F), however a thermal store can run either at 75 degrees, or as high as 90 degrees based on the associated controls.
The type of insulation used on a hot water cylinder depends on the type of cylinder and the location of the cylinder.
For example, if the cylinder is located in an unheated space such as an attic or basement, then an insulation material such as polyurethane foam should be used. This type of insulation is designed to prevent heat loss and keep the water in the cylinder at an even temperature.
