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  

[Square Feet]

Thanks for all the replies. Sorry I wasn't able to respond yesterday, cos I know it's annoying when someone asks a question and then disappears.

I'm not sure if I know how to answer all of your questions but I will try.

 

I live in a wee town in southern Scotland, so nobody here is a shower snob. It just needs to be there so that I can call it a 2 bathroom property when I sell.  If there are flow issues with having both showers on at once then I think that would be for the new owner to find a work around - ie not using them both at once mebbe...  That wouldn't be tested as part of the Home Report survey. It does need to work properly on its own merits though.  The flat is a double-upper on an upside down layout so most of the bedrooms are downstairs, but I am creating a new bedroom upstairs, for which the second shower would be logical. 

 

I don't know a great deal about the hot water system as I didn't get it fitted. I've also only had combi systems in the past. I can do plumbing ie fit new things, adjust pipework etc, but the bigger picture here is a bit beyond my understanding, hence the question. There's a pressure vessel that needs topped up from time to time so I would say it's a pressurised system.

 

The cold water tank sits directly above the hot water cylinder in an airing cupboard type arrangement. It's a substantial size ie 950l x 550w x 600h.  The hot water tank is 1080mm tall by 480mm dia. It copes with two consecutive showers quite easily before the hot water is depleted.

 

The shower downstairs is pretty much what you have linked to @Nickfromwales I think. I remember replacing it like-for-like a few years ago and it costing north of £200.

 

Most of the pipework in the boiler cupboard is 22mm, with the exception of the pipes going to and from the expansion vessel. The pipes feeding the downstairs shower are 15mm. It takes its cold feed from the header tank, not the mains.

 

I'm thinking that I will just need to pony up for another power shower like the linked one. It would be the easiest re electrics too now that I think it through. I don't think a mixer shower would work as I don't reckon there's enough pressure.

Edited 6 hours ago by Square Feet