Second shower install into power shower system

[Square Feet]

Hi all,

I'm currently renovating a property that has a power shower downstairs with a hot water tank upstairs.  I want to fit a second shower in an upstairs room next to the boiler/hot water tank. Does this need to be a power shower also? Is there anything I need to be aware of for fitting two power showers into a system?  I'm just renovating the property to sell so I don't want the expense of doing away with the original power shower, hot water tank etc -I just want to fit a second shower as cheaply as possible so that the place can be sold as a two-bathroom property. Many thanks

[Redbeard]

Quick fix - elec shower, but if you are selling then the costs of compliance may outweigh any savings. Is it a pressurised cyl? If so I cannot see any obvious problem. For various reasons I have only ever used elec showers, though, so others with more direct (or indirect?!) experience may come in.

[Mr Punter]

Fit a shower pump into the cylinder cupboard.  Single impeller if your cold supply is mains pressure, twin impeller if it is a cold water tank.  The negative head ones have a small air chamber that pressurises when the flow stops so the pump will be ready primed.

[Tetrarch]

You could fit a digital shower, but that would be >£500

 

Regards

Tet

[-rick-]

23 hours ago, Square Feet said:

I'm just renovating the property to sell so I don't want the expense of doing away with the original power shower, hot water tank etc

 

Who are you planning to sell to?

 

If you are targetting people who are moving from a city flat to a house then they may be actively looking for 'decent' showers that match those found in modern flats (almost always pressurised systems).*

 

Obviously dumping the tank and pump for a new pressurised system has a cost but it might be worth it if it attracts buyers. (While a pumped shower can work, my experience of them is that they are noisy and that in itself is a turn off)

 

* Showers came up amongst my very mixed income group of London adjacent friends recently and I'm sure we are a weird group compared to average but decent showers was one of the things we all actively looked for when looking for a new property. Just in case it matters, I'm the only one interested in the detail. The others were just wanting a nice shower not concerned how that happens.

[SteamyTea]

Assuming this is a pumped system (twin impeller shower pump) on a vented system  then you run the risk of emptying the loft tank and the DHW cylinder. This  at best caused an air lock, at worse, the cylinder can distort and fail.

If it is a mains pressure system (invented) then no need for a pump.

On a combi system (instantaneous), then most struggle to run one shower, two will give trouble.

 

So it all depends what you actually have already.

[Nickfromwales]

On 11/08/2026 at 12:38, Square Feet said:

Hi all,

I'm currently renovating a property that has a power shower downstairs with a hot water tank upstairs.  I want to fit a second shower in an upstairs room next to the boiler/hot water tank. Does this need to be a power shower also? Is there anything I need to be aware of for fitting two power showers into a system?  I'm just renovating the property to sell so I don't want the expense of doing away with the original power shower, hot water tank etc -I just want to fit a second shower as cheaply as possible so that the place can be sold as a two-bathroom property. Many thanks

With any pumped showers (your’s is likely to be a pumped unit with integral twin impellers by the sound of it) you have the huge problem of the volume of stored water in the CWS. 
 

This single body of stored aka gravity cold water feeds both the hot and cold, one going via the HWC, so you need to be careful here (or just not give a toss and just want it to work on the day?).
 

You’d need to run the existing shower for 10-12 mins and monitor the water level in the CWS, and this will let you work out if it’s capacity would cope if two showers were on simultaneously, and make your plans from there.

 

How is the hot water feed T’d off the HWS? Has a 22mm Sussex flange been added on top, or has someone added it fully properly and fitted a tank boss 2/3 of the way up the side of the HWS? 
 

You can’t connect both 15mm feeds together off a 15mm pipe, FYI.

 

The second shower should be chosen wisely, so don’t go fitting something that outguns the existing one, just match it and then the stored water volume in the CWS won’t become the end of your ‘quick fix’.

 

I used to fit walk in baths for folk and the salesman would brag about how they would fill in no time at all; due to the massive 3.0 bar 22mm twin ST pumps they would power-sell…..

 

Bath would get around 1/3 full, the CWS would go bone dry (with just the piddling cold mains float valve splashing a pint or two every minute back into the mud and feathers), and then you’d wait for the incoming water to the bath to turn to Bisto. Which they almost always did. 
 

£2-3k worth of upgrade then needed, to increase capacity for both CWS and HWS, plus changing all the 15mm pipework to 22mm, and a long list of people on the salesman’s voicemail. 
 

Didn’t do that for long as it was just shocking.

If you can add an electric shower, and add capacity to the CWS quite easily, then fit one of these:

 

https://www.plumbworld.co.uk/mira-elite-se-pumped-electric-shower-98kw-white-chrome-11941001-65-1261689?utm_source=organic&utm_medium=shoppingfeed&utm_campaign=googlebase&gad_source=1&gad_campaignid=22933019676&gbraid=0AAAAAD_lDOgr-ri4UN_SMQRQ_4_HsN5ab&gclid=EAIaIQobChMI4ObmsvqblgMVMZtQBh0qiAX5EAQYAyABEgJpCvD_BwE

 

10.8kw, and as it’s pumping out of a CWS it is absolutely NOT affected by how good a cold mains you have / if someone flushed a loo / if a washing machine fills / etc etc etc. 

 

IIRC there are jumpers inside which can be used to limit the shower-time, via audible beeping before automatic shutdown, to ensure the CWS cannot be drained.

 

Lots of angles here, none ‘cheap’, and if you tell me how cut throat you are happy to go then I can advise accordingly