A couple of variations of hot water cylinders can be fitted in the home, below are the two most popular.Direct:This direct water cylinder uses an electrical heating element to provide its hot water. This is generally termed an immersion heater and requires an electrical supply to be connected, usually fed from the domestic consumer unit or fuse box. A wise choice option for installation in a small flat or apartment. When the heating is done, the hot water is used perhaps to fill a bath. There are quite large versions of this type of cylinder available on the market, which can be fitted internally with up to three heating elements. This will obviously greatly increase the volume of hot water that is supplied. They are available in vented or unvented examples. Chislehurst Plumbers understand these systems. The direct type has an advantage, which is to exploit the different additives fed into the boiler water which can prolong its life.Indirect:Slightly different from the direct, this type of indirect cylinder include something called a heat exchanger that sits inside the shell. A heat exchanger is a copper coil through which the water will run. This system usually receives its heat from a boiler or it can even use solar powered technology. The cold water enters the bottom of the cylinder, and there is normally a small drain cock fitted. The hot water then returns to the hot water cylinder via a connection on the top of the cylinder. There is a heat transfer that takes place between the coil and the water that is inside the cylinder. The two never physically interact. So the name indirect refers to the relationship between the coil and the cylinder water, so the heat is indirectly transferred to the water. A Chislehurst Plumber is well trained in this type of system. This type is available both as a vented or unvented cylinder. Hot water leaves the tank at the top.