How to make sure I can run 2 showers at once

[Soooodenim]

In the process of converting loft to a bedroom with en-suite. Have bought a good shower which is half installed (building team are on hols at the mo) but it’s just a normal shower (not electric).

We’re also redoing our existing bathroom and will get a new shower for that too. Plus we’re getting a new boiler and an indirect hot water cylinder (must be honest, I don’t really understand boilers /cylinders etc). Plumber has also replaced our water mains to increase the flow/pressure.

I’m a bit worried that we should have bought a particular shower for the loft en-suite - perhaps electric? - and that we should buy an electric one for the bathroom we’ve yet to start work on to ensure that both showers can run at the same time (family of 5). Is the type of shower important for this or is the new boiler/cylinder/mains the most important factor for making sure the pressure/heat won’t drop?

It’s too late to change the shower in the loft so I’m worried we’ve made a mistake but I’ve not yet bought the one for the existing bathroom so if I should be looking at an electric one for that bathroom, that’s what I’ll do. Any wise words please??

Is your new system entirely mains water fed (i.e. no header tanks in the loft)?

If so I think you're best off with normal i.e. mixer or bar showers.

An electric shower (i.e. electric heater only - no pump) will not have a good flow rate compared to a normal shower, and you can't use a power shower (with pump) with a mains fed hot water cylinder.

Best way to get large volume of hot water all at once is a megaflow system (unvented cylinder). Probably the cheapest as well as water heated by gas is 1/3 the price of electric (at the moment).

We now have a 300 litre cylinder and can run two showers with no drop in pressure!

You need a bigger mains pipe feeding your house (in a non tank system) via contacting your water company.

if you are in a hard water area I would avoid an electric shower - they really aren;t fit for purpose unless you want to get an engineer out a couple of times a year.

Yes, I'm absolutely fed up with ours and can't wait to see the back of it.

Mega flow cylinder- they are brilliant (particularly if you have a child that likes to take long steamy showers to decompress)

To answer some questions:
I don’t have any header tank in the loft.
We are having a bigger mains pipe put in too.

Is Megaflow a brand name? Because I know we’re getting some sort of big cylinder but I’m not sure what it’s called (sorry to be so clueless!!).

But it sounds like from what you’re all saying that it’s not about the shower, it’s the cylinder and size of the feed into the house that will determine how well the two showers work? So I don’t need to panic that I’ve got the wrong type of shower for the loft???

Thank you all for your comments by the way!!

We had this issue- 2 shower rooms and a bathroom. Unvented cylinder and no tank for lots of hot water. Make sure thermostatic valves on showers so temperatures aren’t affected by other taps/showers.

You don’t need electric one. We have a water tank. And can easily run all three showers, and hot water at sink at once if needed. So if you have tank added shouldn’t be a problem

I’m sorry to be thick - but what’s the difference between a tank and a cylinder???

Also, the shower in the loft isn’t thermostatic -was that a mistake??

Actually - think it is thermostatic. It’s not clearly labelled as “thermostatic” in the brochure but when I look at the installation guide, it refers to “thermostatic.”

Mega flow is a brand.
A large unvented (I think ours is 300) cylinder will give you what we need.
We have this and have 2 bathrooms and run both showers with no issues.
We live in a hard water area and have a water softener system in the utility so maybe that helps

Thank you @TrudyProud !

We have megaflow too, a huge cylinder in the basement. We can have both showers running taps on in thr kitchen to do washing up and flush the loo and everybody still has perfectly good pressure.

That sounds perfect @OakleyStreetisnotinChelsea !

I think ours is 500l, also in cellar. But 300l should be fine for most houses

The real key to multiple showers is to make the best of the pressure and flow you have. If possible use 22m diameter pipe, not the usual 15mm pipe. If possible avoid elbows and joints and use nice smooth curves. Every bit of thin pipe, elbow and joint saps a bit of flow, and lowers pressure at the shower.
22mm tube is more expensive though.

We have a unvented cylinder, widened pipes and water main and we still struggle running 2 showers simultaneously. DH was absolutely fixed on being able to do it so did loads of research and it's only 'ok'. Maybe that's just the comparison between the really good water pressure of one shower!

Aaargh @Oigetoffmylawn that sounds so annoying!! And exactly what I’m worried about!!

It's disappointing. Especially as we were very specific about wanting it. Don't get me wrong, it's doable, and fine if we have guests and all need to be getting ready at the same time, but if you want a powerful, hot shower, then you're best off waiting!

We have a large hot water tank, I love it as now have an airing cabinet that drys clothes overnight

@Oigetoffmylawn so do you have any idea why it hasn’t worked?

Not really. Our unvented cylinder is in the cellar so we do lose slight pressure as we go up the house. And we often moan (to each other) that when we stay with friends/family/in a hotel that their shower isn't as good as ours, so maybe we just have high standards!

If you can accept the water pressure from an electric shower, perhaps a 35kW+ Combi Boiler could meet your needs without the need for installing a large water cylinder.