Or not when you are considering shower performance. Because then it’s the pressure of the water feeding the shower that is far more important than how big the shower head actually is. Hence the success of shower pumps in the UK market which, when connected to a water supply from a cold water storage cistern (cwsc) can change the pressure of water at the shower head from 0.2 bar to 3, 4, 5 or even 6 bar! As every 0.1 bar adds another metre to the head of pressure (effectively raising the cwsc another metre) instead of standing under a shower that has its water stored 2 metres above it, you could be showering under one where the water is stored 60 metres high! In the absence of a standardised height measurement like Wales represents for area, I did a quick bit of research. Niagara Falls (Canada/US border) is 57m high; Victoria Falls (Zambia/Zimbabwe border) is 108m high: Angel Falls (Venezuela) is 979m high. You have to admit that a shower pressure greater than Niagara Falls sounds pretty impressive (if totally unnecessary).

This aspect of size v pressure was clearly demonstrated this month. In early May we visited friends in Suffolk and I showered under a nine inch diameter (300mm) shower head (my first ). That was closely followed by a few days on my canal boat where the shower rose is just one inch (25mm) in diameter. Helen and Anne’s shower is fed from a combi boiler but the pressure in their street is low at about 1.2 bar. The flow rate from their shower was 9.6 litres/minute. This is 2 litres/minute more than our shower at home and yet both I and Suhith found it far less satisfying. To reduce the amount of water coming through a shower head that large the holes need to be further apart. This resulted in lots of cold bits in between the water stream.

The shower on Protea by comparison only provides a flow rate of 5.6 litres/minute, and yet that is coming through a tiny shower rose in a series of tiny streams of water with a pump delivering 2 bar pressure behind it. It is not just the fact that you are dirtier and colder in the winter or dirtier and hotter in the summer (I’m talking relative hotness here, it is the UK after all) than on dry land, that makes the shower on the boat so satisfactory…

I also got to see my cousin’s new power shower with its integral digital temperature gauge. I will be trying it out soon and report back (purely in the advancement of science you understand).

May 2012 – Size doesn’t matter!