Gas Shower

ic

https://forums.moneysavingexpert.com/discussion/comment/82125678#Comment_82125678

Fair point - we had to install a PRV as the pressure is very high without. I think we're at its default 3 bar.

victor2

https://forums.moneysavingexpert.com/discussion/comment/82125661#Comment_82125661

With only two of us in the house, the problem with somebody else running hot water is minimal - only used to make a point after a "discussion"!

We both love the "gas" shower compared to the old electric one, but we did at the same time go from one over the bath to a proper shower cubicle. One possible downside is that if you have a failure on the combi boiler, you can't have a hot shower, but that hasn't happened since we had it installed over 3 years ago (touches wood). Assuming you go that route, do get a good shower with a thermostatic valve.

DiamondLil

Our shower runs off the combi boiler. We frequently have 7 people staying here and, once we understood how it works, using the hot water elsewhere hasn't been a problem.

oldernonethewiser

Currently have an electric shower but when the bathroom is getting redone it will be replaced by one using the combi boiler.

Much better.

Albermarle

https://forums.moneysavingexpert.com/discussion/comment/82125683#Comment_82125683

I have an unvented hot water tank, but only 1.5 bar pressure. One shower on its own is quite strong, but if the washing machine/dishwasher is on, the flow varies. If someone else has a shower the flow drops considerably.

bjorn_toby_wilde

https://forums.moneysavingexpert.com/discussion/comment/82125817#Comment_82125817

@Albermarle is quite right. The most important thing to check is your water pressure and flow.

We had good pressure but an old 1/2” copper water main. Our shower’s performance from an unvented cylinder was affected by running other taps until we upgraded the main.

casper_gutman

We have a shower fed by a 30 kW gas combi boiler. It's fine. The drops noticeably when someone opens another hot tap fully, but it's no more than a minor annoyance. The temperature doesn't change though - just the pressure. You should find the temperature stays pretty stable as long as you have a good quality thermostatic shower.

I wouldn't try to run two showers off it at once though - our second shower is electric, a choice we made in the interests of using up excess solar generation in summer and still having a source of unlimited hot water in case of a problem with the boiler or gas supply.

FreeBear

https://forums.moneysavingexpert.com/discussion/comment/82125817#Comment_82125817

I had a gravity fed vented hot water system. Pressure & flow rate was [redacted] at the best of times. Having switched to a combi, flow rate is still poor (9-10l min), so a shower fed by the boiler is not going to be brilliant. And should someone turn on a tap elsewhere in the house, flow rate will drop even further…

I'll stick with the thermostatic electric shower for now. Still suffers from the issues above, so no real advantage to replacing it. Keeping it does mean I can still take a shower should the gas boiler develop a fault.

Bigphil1474

We have an electric shower and it goes cold if someone turns a tap on downstairs. Thinking about it, we've always had an electric shower going back 30 years. They are usually cheaper and easier to install, but cost more to run. I'm in and out in a few minutes so cost isn't huge for me though.

WIAWSNB

https://forums.moneysavingexpert.com/discussion/comment/82130685#Comment_82130685

Goes to show that if mains water pressure and flow are borderline, neither shower type will work successfully at times. In fact, I think the gas combi is less likely to fully shut down with poor flow compared to the electric one.

(For anyone lucky enough to have a powerful combi - say 35kW and above, like IC's - with a decent mains F&P, and folk regularly wishing to use more than one shower at a time, I think a useful thing to do could be to fit quality isolating valves to each mixer - lever or thumb-turn type - and throttle down each supply to provide a 'good' shower when shower is set on 'max', as opposed to a crazy one. That way, even at max control flow, each shower will draw less than what the combi and supply is capable of, so there should be spare. Some folk jump into a shower, and just slam the valve to max without a thought. If two folk do that, then, well, you know…)

Cordie, as mentioned, you should get these F&P figures from your plumber before considering a 'combi' shower. Having said that, assuming you currently have a bath installed, you will get a very good idea by placing a pan under each bath tap in turn - it'll be interesting to see how the H&C compare - and running it FULL ON for a timed 6 seconds each. Measure the number of litres from each tap, and 'times' that figure x 10 to get 'litres per minute'. Please report back.

Will this shower go over an existing bath, or will it be a separate cubicle?

Both types will require pipes to be run (two for the mixer type - but together, so no biggie), but a cable for the electric plus a new MCB in the CU and a sparky. The thermo mixer will likely be more tricky to install at its location, tho' - two pipes come through, and it all needs neat and careful mounting (the electric unit is just a box stuck to the wall that hides everything).

The actual shower units - a good electric for around £120, and a similar quality named-brand thermostatic mixer for around £150. Ie, nothing really betwixt them.

So, unless the cable run is really awkward, there shouldn't be that much difference in cost between them, and it could go either way.

As for which one to choose, to me there's no contest - combi mixer every time for the quality of shower. A 30kW combi will give three-plus more water flow, at the same running cost (gas being three times cheaper). A combi-driven shower will also give you the option of a 'diverter' - rain head and handset. And, a thermostatic shower just looks better…