Shower heads and pressure

[H F]

We have decent water pressure in the house, which does suffer a tad when you’re showering and someone else opens a tap. That aside, is there a metric for showers that we can look for that shows the amount of pressure a shower head can generate?

[PeterW]

Pressure or flow ..? 
 

Pressure is perceived by the “blast” from the shower head but is easily modified with a new shower head with less or more holes. 
 

9l/min is a decent flow, just then need to ensure you have the static and dynamic water pressure behind it to give you the “experience” you want. 

[H F]

Is the 9l/min metric determined by the shower head?

[SteamyTea]

It is a combination of pipe diameter, cumalative resistance and pressure.

There are two pressures, static (tap closed) and dynamic (tap open).

 

https://www.copely.com/tools/flow-rate-calculator/

 

Edited November 18, 2019 by SteamyTea

[Temp]

A shower head cannot improve water pressure over that from the supply, All a shower head does is trade off pressure for flow and change your perception ...

 

a) With no holes in the shower head you would get best pressure but no flow.

b) With lots of holes or one large one you would get no pressure but best flow.

 

In between there are a range of possibilities. Shower heads with a few small holes tend towards a) where as big rain type heads tend towards b). 

 

A "good" shower generally needs adequate pressure AND flow rate, a combination that may not be possible from the supply. In which case improvements to the supply can be made (fatter pipes, pumps, accumulators depending on the cause). Before going down that route measure the static pressure and separately the flow rate (in L/Min) with NO shower head connected. If they are both good then it should be possible to find an acceptable shower head without needing to improve the supply. 

 

Some/many heads have restrictors or restrictions in them that effect both perceived pressure and flow. Some can be removed some not. In one case I took apart a shower head and drilled out a hole in the swivel ball to reduce the restricting effect it was having. Last time I looked a few advertiser's on Amazon mentioned they had removable restrictors. Some heads also have filters in them that get blocked/scaled.

 

 

 

Edited November 19, 2019 by Temp

[Onoff]

Do the claims for venturi type shower heads / valves stack up or is it snake oil?

[Ferdinand]

3 hours ago, Onoff said:

Do the claims for venturi type shower heads / valves stack up or is it snake oil?

 

Build one and find out ?

[SteamyTea]

5 hours ago, Onoff said:

venturi type shower heads

Are these the ones that use the mains water pressure to draw the hot from a vented cylinder.

The sort the cheapskate don't buy as we get the cheapest pump from Screwfix.

Or the ones that pull in air?

Edited November 19, 2019 by SteamyTea

[Onoff]

39 minutes ago, SteamyTea said:

Are these the ones that use the mains water pressure to draw the hot from a vented cylinder.

The sort the cheapskate don't buy as we get the cheapest pump from Screwfix.

Or the ones that pull in air?

 

I thought they pulled in air.

 

Seem to remember a Victorian fountain in some stately home using the system to great effect...

[SteamyTea]

25 minutes ago, Onoff said:

I thought they pulled in air.

These were a water saving idea.  They should have been a soap saving idea as you learnt the first time that there was not enough water to wash it all off.

 

[Temp]

Two different things...

 

1) Aerated Heads - suck in air to make a low flow rate feel larger that it is by adding bubbles.

2) Venturi Heads - try to improve the flow from a gravity fed hot using energy from the mains pressure cold.

 

I've no experience of venturi heads.

 

Aerated heads don't really do it for me. I'd rather have a full pint of beer than one with a large head on it ?  

 

PS: Aerated heads also use a venturi but it's to suck in air instead of hot water.

 

 

Edited November 20, 2019 by Temp

[Temp]

Not actually sure who makes venturi showers (of the type designed to boost the hot flow). Ideal Standard used to make one called the Trevi Boost but I think its out of production.

 

 

 

 

[Gone West]

1 hour ago, Temp said:

Ideal Standard used to make one called the Trevi Boost but I think its out of production.

We had a Trevi Boost in the old bungalow which lasted getting on for ten years without any problems.