Am I going to notice much difference? If I go for a 10.8kw shower, I’m going to need to spend £150 on fitting a 10mm cable.

Am I right in thinking that th extra power allows the water to be heated faster, so you can turn the flow up higher and achieve the same temperature?

I was thinking of getting a Mira Sports shower, with air boost – sounds like fun.

That’s a 20% increase in rated power so there will be a difference, although given that you can’t compare them side by side whether you will notice anything is another question.

Am I right in thinking that th extra power allows the water to be heated faster, so you can turn the flow up higher and achieve the same temperature?

Yes.

I went from 7.2kw to 8.4kw and it was noticeable but probably moreso as it was previously lower powered than yours, in a cold flat, in Scotland.

If you’re going to be in the property for a long time, I’d say do it.

20% more powerful, which I reckon would definitely be noticeable. I would pay the extra.

We’ve got a 10.5kW shower and in the summer it’s ridiculously powerful. In the winter, when the inlet water is that much colder it is perfectly fine, but it is a lot less powerful due to the reduction in flow rate through the element.

I wouldn’t want anything less than what we have now, purely for during the winter. In the summer, I often use it on eco mode, which reduces the power and it’s still hot (and powerful) enough.

was thinking of doing the same until i fould a little trick with our mira sport.

turn heating dial up to V hot, wait until water is v hot then back off heating dial slowly until desired heat vs flow is achieved. I seem to get better flow for same heat of water with that method.

sounds a bit daft but works well enough to not warrant replacing the shower!

I’m trying to think of some way that that would work, millhouse. Unless the shower has a massive heatsink to stabilise temperature then I can’t think of one. Electric showers of the type we’re talking about here are really simple.

They provide X energy per second (which is the kW figure) which allows you to raise the temperature of a quanity of water by a fixed amount. If you turn the dial to hotter, you let less water flow so it gets hotter (same energy, less mass of water) or if you turn it to colder, you get more water flow so it’s less hot.

In your example, as you turn it down, the water flow will increase, reducing the temperature but that’s directly linked to the water flow, not whether you started hotter or not.

Assuming you are staying there a while and the water pressure to the property is good then yes. If you have poor water pressure you may not notice any significant improvement anyway.

I think my water pressure is OK, so I’ll go for it. Or does anyone have a way of measuring water pressure? If this is the same a flow, then presumably you can see how long it takes to fill a litre container etc?

I believe it is the same. Plumbers have a nifty little cup (weir cup?) that calculates it.

Sorry for slight highjack but can anyone explain why the pressure to our shower is low (comparably) to the rest of the house please?

Could be anything – you haven’t supplied any details yet.

Power shower? Gravity fed? Mains pressure? Electric?

clubber:

slightly confused by it myself but it seems to work! go try it…

Electric shower (non-power), pressure-fed.

So direct from the mains (ie, not from a header tank?)

There may be a restrictor valve (ball valve) in the cold feed to protect the shower from too high a pressure. Check upstream from the shower.

Use a screwdriver to open it up a wee bit.

OP – if you’re there for any amount of time, get the 10.8kw.

get the most powerful one you can afford/power supply can handle.
you can always turn it down but if you have the less powerful one you cant turn it up if you are already on full!

I measured our water pressure using a screw-on hosepipe adapter with an old inner tube valve pushed through it and a shock pump with a gauge on. Nothing exploded, the pump still works and I didn’t die.

There may be a restrictor valve (ball valve)

From the mains. Yes there is a valve, it is all the way out (full flow).

One of these?

No, a stop-cock tiggs. (like a tap but with 2 lugs on it)

Can you replace the 10mm cable yourself to save money?
Mine was easier than I thought.
I would also make sure there’s a toggle pull-switch by the bathroom door.

suspect millhaus is also heating the hose and shower head before turning up the flow….

that could be part of it!