New Shower Options

[leccyblue]

Hi All,

We've recently created a new ensuite, and have moved the existing electric shower circuit from the main bathroom into this.

We are now looking to refit the main bathroom and considering our shower options. I've spoken to a local electrician who says we could have a second electric shower if we used a shower priority unit to ensure only one was used at once. This would be satisfactory however we'd like to explore other options that would allow two showers running at the same time.

We live in a bungalow and have a gravity fed hot water cylinder (120L) in the airing cupboard with a header tank in the loft. This is heated by our oil fired boiler up to 60oC. The distance between the bottom of the header tank and a new shower outlet will be around 800-900mm approximately. We have very good mains pressure cold water.

I've looked into a million options from venturi mixers to a new unvented pressurised tank and roughly understand the differences between them all but am finding it difficult to know what to do for the best.

What we're looking for is the least cost option that would provide a decent shower that is at least as good as a 9kw electric shower. We're not afraid to replace the tank etc if this is necessary. We don't want the hot water depleted after a few minutes, my wife likes to take long, hot showers (15 mins).

What would be the best option in your opinion and a rough estimate of cost? What would you do if this was your house?

Thanks

 

[terryplumb]

If your happy with the flow from your electric shower ,and would be just as happy with second shower having similar performance ,fit a micro pump on the hot supply from cylnder to a thermostatic shower valve. The cold supply to it must be from the loft tank.

 

[flameport]

a decent shower that is at least as good as a 9kw electric shower.

Electric showers are not decent - they are the absolute minimum in terms of flow, and far worse than other options. Generally recommended if there really is no other choice.

Options:

1 Pump used with the existing cylinder. Cheapest, but pumps are noisy so that may be a problem depending on where the cylinder is and when showers are used. Old cylinder may not have sufficient capacity particularly if it is old and full of scale.
There are some variants to this such as showers with the pump built in or showers with a remote mixer/pump unit.

2 Replace cylinder with an unvented - significantly more expensive, but no noise and would also allow a larger size cylinder to be fitted, and the new one is likely to reheat far quicker than the existing one, and will certainly have far better insulation which will reduce heat losses. However this does require a good mains water supply with decent pressure and flow, testing is required before going with this option.
If this is a suitable option, you would also benefit from decent pressure hot water to all other outlets and the loft tanks would be removed.

3 A second electric shower used with the priority unit. By far the worst option but still likely to be relatively expensive both to install and use.

What would you do if this was your house?

If pressure and flow were suitable, option 2, and also dispose of the other electric shower and have both from the cylinder.
Cylinder would also have an electric immersion heater fitted to provide hot water in the event the oil boiler failed.

 

[leccyblue]

If your happy with the flow from your electric shower ,and would be just as happy with second shower having similar performance ,fit a micro pump on the hot supply from cylnder to a thermostatic shower valve. The cold supply to it must be from the loft tank.

Thanks Terry! Is that something like the SP2B? I did see those on Amazon, but the reviews were very mixed. I also wasn't sure if our cold header tank was large enough to supply both the cold side of the shower valve and the hot water cylinder? It's not very big, I'd estimate 50 or 60 litres. Would the new cold feed from the header need a micro pump too?

 

[terryplumb]

Yes that's a micro pump. They will boost your flow to similar to electric shower ( which are not great as flameport said above ,typically around 5/6 litres per minute at best) but if your happy with that it's a cheap fix. As most showers water usage is hot ,with a little cold ,it's the amount of stored hot water thats important. 15 mins at 6 Lt/ minute
Would use 90 litres of water and most of it hot !!
Compared to larger pumps , at 3 bar for instance ,there is no comparison ,they will give miles better performance,so anyone who is / was expecting a micro pump to give them a deluge would be disappointed !! So it's horses for courses. What you stated that you wanted ,and cheaply ,is what I responded to.
Boosting the hot only ,works with a micro pump ,but sometimes you have to boost the cold also. Last one I did only had the hot boosted. If you found the cold is needed ,after fitting just one to hot ,the second pump is cheaper and can be fitted later.
As you told us your cold mains pressure is very good ,I doubt you would have a problem with tank replenishment whilst electric shower was running at the same time. But would need confirmation of actual pressure.

 

[leccyblue]

Thanks Terry and Flameport.

I guess we are used to an electric shower as it is all we have had for the last 10 years. We find it adequate, obviously it's much better in the summer than winter. Whatever happens, we would likely keep the electric one in the ensuite so that we have an instant option in the event of hot water depletion etc.

It's sounding more and more like our existing hot water cylinder and header are unlikely to be sufficient for a 15 minute hot shower. We might have to bite the bullet and go for an unvented cylinder. Any idea what me might expect to pay for the installation of one assuming we have a decent enough flow? We are in the east of Lincolnshire.

I guess the other option would be to look at replacing our existing boiler with a combi. It is very old - probably about 20/25 years - it's an HRM wallstar but has been extremely reliable for us and the guy who does our servicing recommends we should keep it running as long as we can as parts are still widely available and newer boilers, especially combi, are not as reliable and more expensive to repair?

Thanks to you both for taking the time to reply.