The amount of water available is an important factor to consider when choosing to buy a new tap. The cold water feed is usually supplied by mains pressure and so generally not of importance as not much can be done to improve this.
It is important however to make sure that you have the correct amount of hot water pressure to get the best functionality from your tap. Although all taps would work, to get the best flow from your tap you need to check the pressure of the tap and that of your system match.
Water pressure is measured in three common ways:
- head (m)
1 bar = 10 metres head = 14.5 psi.
Domestic hot water systems generally fall into three categories:
- Mains pressure combination boiler
- Low pressure gravity system
- Mains pressure unvented system
For more information on types of water systems view our blog post here.
A mains pressure boiler output is typically around 20 psi = 1.8 bar = 18m head (refer to your boiler instructions manual for full details). This available pressure means most taps should give good flow rates on the hot side with this type of water system.
With a low pressure gravity system, the pressure it offers is determined by the height at which the base of the cold water tank (the bottom of the tank) is situated above the outlet (shower head/tap). The amount of pressure is calculated in bar and is worked out to be roughly 1m fall = 0.1 bar of pressure, so if the vertical distance was 5m this would roughly equate to 0.5 bar maximum available pressure, the route that pipes take though and the amount of bends can reduce the available pressure. With this kind of system you will need to install a low pressure tap to get the maximum flow on the hot side. You should also check the available cold water pressure if you live on the higher floors of a tall building or draw water from a private supply.
Mains pressure unvented systems are normally around 1.5 - 1.8 bar (refer to system manual for full details) so would be suitable for most taps.
The pressure a system offers gives you a rough idea of the type pf pressure that you have. If you want to check in more detail or find out your specific water flow rate, view our blog information guide to water pressure here.