What is a power Shower?
In a normal plumbing system where there is a hot water storage tank (normally in an airing cupboard) and a cold water storage tank (normally in the roof space) the "power" or pressure is determined by the capacity of the cold water tank and the height it is between the shower outlet (spray) known as "head " simply put the higher it is the better the pressure, there are other factors involved, such as pipe sizing, the amount of bends or elbows in the pipe and the distance the tank is away from the shower, as any horizontal pipe runs will reduce the pressure.
In most cases by having a good sized cold water storage tank, at the right height with a good quality shower mixing valve and rose, you should get a really good shower without the extra complications of extra pumps and valves.
The term Power showers has different meanings to many people, so this would be a good time to look at the different meanings.
The term Power Shower has been used for many years to describe an electrically heated shower, where the water is heated independently from the rest of the hot water system, and used mainly where there is inadequate pressure or flow of water from the normal plumbing, that means in real terms the cold water storage tank in the roof space is not high enough above the head of the shower.
The main problem with this type of shower/heater is that to get enough water heated to get a "Power shower" you also need a powerful electrical supply, so that means running a heavy power cable directly from the consumer unit to the heater and a "mains" water supply pipe taken directly to the "power" heater, water flow is then controlled to determine how much water can be heated (instantaneously) for you to have a shower with.
The hotter the shower, the slower the flow, reduce the temperature and you will get a more forceful shower, in the summer you can experience a warmer shower with more pressure, because the incoming water to the house is already warmer than in the winter, so the shower heater doesn't have to work so hard!
Shower pumps.
More recently the term "Power Shower" has meant having a "booster" pump fitted, and this works in line with your existing "gravity" plumbing system, normally this means that you have a cold water storage tank situated in your roof space with a hot water storage cylinder in your airing cupboard, and if this doesn't give enough pressure in your shower, then a pump can be fitted to give more flow and more pressure.
Fitting a pump can give you a very good pressure at your shower and by choosing different strengths of pump you can have a very powerful shower capable of of pumping larger shower heads and multiple body sprays, however it is very important to understand that a pump can not solve bad plumbing, so it is important to have the overall design checked first to make sure that the chosen pump is going to be compatible with your plumbing system.
Combination boilers.
If you are having major plumbing and heating work done, you could choose to do away with with the hot and cold storage tanks and have a combination boiler fitted instead, and as this works directly from the incoming water pressure, with the water being heated instantaneously by the combination boiler, you will then have balanced pressure at the hot and cold taps, and at your shower mixing valve. So, depending on the water pressure that you have at your kitchen tap, you should get a pretty good "power shower" without the need of a pump.
The disadvantages of a combination boiler is the flow rates that you will achieve, although the pressure is high enough to give a good power shower, the actual flow rate is low, and that's fine for your shower where you do not need high volumes of water, but when it comes to running a bath, you may need to wait up to twenty minutes to get a decent bath full!
A Water Softener is a must with combination boiler.
Because a combination boiler heats water directly from the incoming water mains pipe it is very susceptical to Hard Water and in exactly the same way as your kettle "scales up" so will your combination boiler, the main difference however is your kettle costs very little compared with a boiler and can be descaled or replaced easily, your boiler cannot, it will also start to use more and more costly energy to heat your water and will also slow down the flow to your hot water taps and shower.
