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Search for a Mira Sport review and every result on the first page belongs to somebody selling it. Mira's own site takes five of the ten slots, the rest are Amazon, B&Q, Screwfix and a PDF of the installation manual. Not one page tells you the thing that actually decides whether you should buy one, which is whether your bathroom can take it and whether your consumer unit can feed it.
Three things came out of putting this page together. The same unit sells for £209.99 at one merchant and £267.99 at another on the same day. The two-year guarantee only exists if you register it, which is stated in the small print and almost nowhere else. And the model people most often buy, the Sport Dual with the big drencher head, needs a full bar of mains pressure where the rest of the range will run on 0.7.
The basis for this review: manufacturer specification, current retailer listings and the installation documentation, plus 16 years of selling electric showers over a plumbers merchants counter. I have not fitted one of these and I am not a plumber or an electrician. Where the job needs a qualified person I say so rather than talk you through it.
Which Mira Sport are you actually looking at?
This is the question behind most of the confusion, and it is the second most asked question on the search results page. "Mira Sport" is not one shower. It is four distinct units at four very different prices, sharing a case and a name.
Mira Sport specifications compared
| Model | Min pressure | Flow at minimum | Head | Temp control |
|---|---|---|---|---|
| Sport Max with Airboost 9.0kW | 0.7 bar | 4 L/min | 120mm handset | Manual |
| Sport Thermostatic 9.0 / 9.8kW | 0.7 bar | 4 L/min | 120mm handset | Thermostatic |
| Sport Dual 9.0 / 9.8kW | 1 bar | 6 L/min | 250mm drencher plus handset | Manual, pressure stabilised |
| Sport Multi-Fit 9.8kW | 0.7 bar | 4 L/min | 120mm handset | Manual |
One thing worth flagging, because it is the sort of thing that gets a shower blamed unfairly: the retailers do not agree on the maximum flow figure. Toolstation quotes up to 12 litres a minute for the Sport Max, Screwfix quotes 8 for the same unit. The honest reading is that the higher figure is a best-case with the eco setting and full mains pressure behind it. Budget on the lower one and you will not be disappointed.
Will it work in your house?
Two separate questions, and people usually only ask the first one.
The water side
An electric shower takes cold water straight off the rising main and heats it as it passes through. That means it needs a cold mains supply at the shower, not a tank-fed cold, and it needs at least 0.7 bar of pressure at the unit (1 bar for the Sport Dual). If your cold taps upstairs dribble rather than run, that is the number to check before anything else. Our guide to water pressure and how to measure yours covers how to test it properly.
The upside of the cold mains arrangement is the one people forget: an electric shower works when the boiler is dead. That single fact is why merchants sell so many of them into second bathrooms and en suites, and it is a genuine argument for having one in the house even if your main shower is a mixer fed off the hot supply.
The electrical side, which is where the money usually goes
A 9kW shower pulls roughly 39 amps. It needs its own dedicated circuit from the consumer unit, its own suitably rated breaker, RCD protection and a means of isolation, usually a 45A ceiling pull cord. The cable has to be sized for the load, the length of the run and how it is installed, which is an assessment against BS 7671 rather than a number anyone can quote you off a web page.
The trap is going up in power. People replacing an old 7.5kW or 8.5kW unit with a 9.8kW one assume it is a like-for-like swap. Often the existing cable and breaker were sized for the old load and are not adequate for the new one, and then the cheap shower has a few hundred pounds of electrical work attached to it. If you are increasing the kW rating, get the circuit assessed before you buy, not after.
If you are still deciding on a power rating, our breakdown of electric shower wattage sets out what each step up actually buys you in flow, and the most powerful electric showers covers the 10.5kW and above end where the circuit question gets sharper still.
What the Mira Sport actually costs
This is where the page earns its keep. The spread between merchants on identical stock is large enough that it is worth ten minutes of checking, and buying direct from Mira is consistently the most expensive route.
| Model | Screwfix | Toolstation |
|---|---|---|
| Sport Max with Airboost 9.0kW | £209.99 | £267.99 |
| Sport Thermostatic 9.0kW | £279.99 | Not stocked at time of checking |
| Sport Dual 9.0kW | £349.99 | Not stocked at time of checking |
A £58 difference on the same box, on the same day, from two merchants half a mile apart in most towns. That is not a clearance line or a damaged carton, it is simply how electric shower pricing works. Check both before you order.
The model worth buying
Best of the Sport range
Mira Sport Max with Airboost 9.0kW Electric Shower
- 9.0kW, cold mains fed only
- Airboost raises perceived flow by up to 30% without using more water
- 0.7 bar minimum pressure, 5 bar maximum
- Clearscale and dual element construction to slow limescale build-up
- Sensi-flo anti-scald protection and phased shutdown
- 215mm wide, 358mm tall, 75mm deep
Pros
- The Airboost genuinely helps where mains pressure is adequate rather than strong
- Lowest pressure requirement in the range at 0.7 bar
- Retrofits onto most existing Mira inlet positions, so a Mira-for-Mira swap rarely needs tiling work
- Widely stocked, so spares are easy to get hold of
Cons
- Manual temperature control, so it holds the power setting rather than the temperature
- Retailers disagree on the maximum flow figure, which makes the headline number unreliable
- The two-year guarantee has to be registered to exist
- Going up in kW from an older unit may mean a new circuit, which can cost more than the shower
Of the four Sport variants this is the one that makes sense for most houses. The Airboost does something useful at the pressures British houses actually have, it has the lowest pressure requirement in the range, and it is the cheapest of the four. Step up to the Thermostatic only if a vulnerable person uses the shower. The Dual looks the part but wants a full bar of pressure and costs two-thirds more.
The guarantee, and the condition nobody reads
Every Sport listing carries the same line: two year manufacturer's guarantee, registration required, terms and conditions apply. Those three words in the middle do a lot of work. An unregistered unit that fails in month eighteen is a conversation you do not want to be having.
Register it with Mira the day it is fitted, keep the receipt and note the installation date somewhere you will find it again. It takes five minutes and it is the difference between a warranty claim and a new shower. This is not a Mira-specific complaint, most of the industry does the same thing, but it is worth saying plainly because none of the retailer pages do.
What goes wrong with them
"Common problems with the Mira Sport" is one of the most asked questions on this search, and not one of the pages ranking for it answers it. Here is what brings electric showers of this type back to the counter, in rough order of frequency.
The overwhelming majority of what comes back is limescale related, which is why the Clearscale and dual element features are more than marketing in a hard water area. If you are anywhere from the Midlands south and east, limescale is the thing that will eventually kill the shower. Our electric shower fault-finding guide works through the diagnosis in more detail.
How long should a Mira Sport last?
Mira does not publish a design life and I am not going to invent one. What I can tell you is what the pattern looked like from behind a trade counter: in a soft water area an electric shower of this class, used by a normal household, tends to be a ten-year-plus item. In hard water, five years is closer to typical, and units in heavy family use fail sooner than that.
The variable is water hardness far more than brand. A Mira in Guildford and a Mira in Manchester are not the same product in practice, and anyone quoting a single lifespan figure for the whole country is guessing.
Mira or Triton?
The honest answer from the counter is that both are competent and the choice usually comes down to what is already on the wall.
Triton generally comes in cheaper at equivalent power and their entry units sell in enormous volume, which means spares are everywhere. Mira sits slightly above them on price and on the feel of the controls, and their retrofit compatibility within their own range is good, so a Mira-for-Mira replacement rarely disturbs the tiling. If you are replacing a Mira, buy a Mira and save yourself the drilling. If you are starting from nothing, price the two on the same day and take whichever is cheaper, because at this level the difference between them is smaller than the difference between two merchants' prices for the same unit.
Where a Mira Sport is not the answer at all is if you want more flow than 9kW gives. That is a different conversation, covered in our roundup of the best electric showers.
Frequently asked questions
Are Mira Sport showers any good?
Yes, within what an electric shower can do. They are well made, widely stocked, easy to get spares for and their retrofit compatibility is genuinely useful. What they cannot do is produce the flow of a decent mixer shower, because the physics of heating water instantly with 9kW sets a hard ceiling on that.
What is the difference between the Mira Sport and the Sport Max?
Sport Max is the version with Airboost, which draws air into the water stream to raise the perceived flow by around 30% without using more water. The variants also differ on control type and head: Thermostatic holds a set temperature, Dual adds a 250mm drencher head and needs 1 bar rather than 0.7.
Can a Mira Sport run off a hot water supply?
No. Every unit in the range is cold mains fed only. Connecting one to a hot supply will damage it and will not be covered by the guarantee.
Can I fit a Mira Sport myself?
The plumbing side is within reach of a competent DIYer on a like-for-like swap. The electrical side is notifiable work under Part P in England and Wales and needs a registered competent person or a building control notification. Fitting the shower and having someone qualified do the electrical connection is a normal arrangement.
Do I need a new cable if I go from 8.5kW to 9.8kW?
Possibly, and it has to be assessed rather than assumed. The answer depends on the existing cable size, the length of the run, how it is installed and the protective device at the consumer unit, all judged against BS 7671. Get it checked before you buy the shower, because the circuit work can easily cost more than the unit.
What is the most common fault on an electric shower?
Restricted flow from a blocked inlet filter or a scaled-up head, by a wide margin. Both are cheap and often fixable without a call-out. The most common terminal fault is a failed heating element, which on an out-of-guarantee unit usually means replacement rather than repair.
Related guides
- Best electric showers, for how the Sport compares with the rest of the market at this price
- Electric shower wattage explained, if you are still choosing between 8.5, 9.0 and 10.5kW
- How electric showers work, for the plumbing and electrical basics in one place
- Energy efficient electric showers, with the running cost arithmetic at current rates
- Electric shower not working, for diagnosis before you spend anything
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