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Steam mops: are they interfering with your radio?

Household chores seem much less of a drag when you can do them to music. But what if your cleaning equipment interferes with your tunes? Our testers noticed this with some steam cleaners in our latest tests.

Interference from mobile phones is something we’re used to. The familiar blip and buzz from the radio or speakers or the jittery picture on TV when you’ve left your phone too close.

But in our latest steam mop tests, we found something unexpected: we heard interference from our digital radio when using a couple of the steam cleaners. When we switched the water pump motor on, there was interference, but when switched it off, it stopped.

Unexpected interference

In 2013 we looked into a report about an energy-saving LED lightbulb that turned off a DAB radio when it was switched on. So, in true Which? style, we sent a batch of cheap generic LED bulbs to the lab for testing. We discovered that when a digital radio was placed within a few metres of the switched-on bulbs the signal went fuzzy. But, when the radio was only a few centimetres from the bulbs, it cut out completely.

Nearly 500 of you got in touch with your experiences and reported interference with other products too, including sound bars, TVs, digital hearing aids and solar panels.

Is steam mop interference a problem for you?

Electromagnetic interference is usually behind this. For example, electrical currents moving through the circuits in your steam cleaner might have a similar frequency to the radio station you’re tuned into. Household devices, from TVs to washing machines, have to pass European EMC (electromagnetic compatibility) tests before they can go on sale. Usually, an appliance will be designed to limit the amount of interference they’re likely to be affected by, or liable to cause. But this doesn’t eliminate all possibility of interference.

We’re interested in your stories to find out how widespread a problem this is. Have you noticed interference when using your steam cleaner? If so, let us know, including the make of steam cleaner you were using, the type of interference you heard and the device it affected.


I have not heard of a steam cleaner causing radio interference, but it illustrates the problem that many electrical appliances can cause interference. This has always been the case. In the days when we were using AM radios, motors, thermostats and other switches could be a problem and it was common practice to include suppressor(s) to prevent interference. The same was true with the spark ignition systems of petrol engines in cars.

Modern products have the additional problem of electronic circuitry operating at high frequency, notably switch mode power supplies that take the place of transformers and power controllers that can control the brightness of lighting (dimmers), motor speed and heating.

Electrical products have to comply with regulations to carry the familiar CE mark. These include compliance with electromagnetic compatibility (EMC) regulations. The manufacturer has to declare compliance and there is no requirement for independent testing.

Electromagnetic interference follows the ‘inverse square law’ so is much more of a problem if the radio is close to the source of interference. The fact that most radios use built-in aerials rather than external ones like a TV is one of the reasons that radios tend to suffer more interference than TVs.

We could do with some advice from Which? about what to do if we buy a product that causes radio interference.

In the early 80s I was living in a semi-detached house and suffered interference that appeared to be coming from the adjoining house since it remained even when I switched off my supply at the consumer unit. I reported the problem, someone came to investigate and found that it was my neighbour’s TV that was the causing interference. The TV was replaced and I had no further problem.

The motor could be checked to see if it is labelled with the relevant standard and CE mark or the machine manufacturer asked to supply evidence of EMC compliance.

I would have expected that the appliance manufacturer that would be responsible for EMC compliance and that they would be responsible for using a compliant motor in their product.

It would be interesting to know what would happen if a manufacturer decides to use a different brand of motor in their product, either because the original brand is not available or that an alternative brand is cheaper. Electromagnetic interference is not just dependent on individual components but how they are used together, as we have seen in the Conversations about LED lighting.

wavechange, the appliance manufacturer is responsible for the whole product. However, components used should individually comply with appropriate standards so it would be sensible as a starting point, if the motor is accessible, for Which? to see if it is appropriately marked. I assume this might be a simple single speed switched motor without additional circuitry.

I was going to suggest that Which? ask the supplier for evidence of EMC but presume they would already have done so.

Malcolm – Have you any idea how an manufacturer would handle EMC compliance if the decided to switch to a motor from a different manufacturer? Would they rely on the fact that the new motor is compliant or would they carry out compliance testing of the whole product?

I know that the BBC handles complaints about radio and TV interference on behalf of Ofcom. I am not sure what an individual should do if they buy a product that causes radio interference. Maybe a steam mop or one of the many brands of LED lighting that have caused grief for people, as reported in our other Conversations. In that position, I would obviously want the retailer to replace the non-compliant product. If my steam mop was exchanged and the new one caused the same problem, I would want to take this further. The obvious solution seems to be to contact Trading Standards but many of us have experienced the problem that they don’t seem interested in pursuing problems on behalf of the individual, and focus their efforts on dangerous products and frequently reported problems. If that is the case, the interference problem may not be resolved unless the manufacturer receives numerous reports of the same issue.

wavechange, a reputable manufacturer would, I believe, use their technical knowledge to decide whether using a compliant component from an accredited supplier would be satisfactory. i’m sure many products contain components that have alternative suppliers – no manufacturer wants total reliance on one component supplier.

The problem with an individual reporting interference is they have no means of testing properly, so it is anecdotal. There needs to be an accumulation of complaints for the authorities to become involved. I would suggest this is where some consumers association could, for example, collate information – but it would have to publicise its role. It would also need funding to administer and test.

I feel, probably like you, we need a simple, straightforward and more over effective means of reporting product problems which results in action.

It would be interesting to pursue the problem and what action we can take. I hope that Sarah does not mind that some of us are more interested in electromagnetic interference (EMI) in general rather than this problem in the context of steam mops.

Thankfully, DAB and FM radio do not suffer nearly as badly from interference as the earlier AM radios. I have been using a 1967 radio on long wave to test for EMI and the worst example I have found is my Miele vacuum cleaner, which obliterates reception at a distance of two metres. An FM/AM portable shows slight interference on FM and DAB is unaffected.

grumpypete says:
16 February 2015

I suspect that EMI is increasing, due to the proliferation of electrical/electronic equipment, although it is not obvious as few of us listen to AM radio stations. Admittedly this interference is changing as it is mainly coming from high frequency sources in low energy lighting/brushless motors(digital?) etc. Unfortunately production problems can lead to a change from original specification, and if this is not picked up in testing, if any, we will find out the hard way. I have two battery charges for professional quality drills which interfere with my DAB radio if it is too close, which is a pain if they are plugged in to the same extension lead. Mind you, these mostly pale into insignificance compared to the good old days, trying to watch television living next to a busy road with lots of poorly suppressed ignition systems!

grumpypete – Few may listen to AM radio, but it’s the easiest way that the general public can establish the amount of EMI being produced by household electrical products. As you say, it’s not just cheap products that create interference.

With the proliferation of products that can potentially cause interference and wireless devices that are broadcasting signals, perhaps the way forward will be internet radio.

I would be very interested to know if the test labs used by Which? check for electromagnetic interference during product testing.

In her introduction, Sarah mentions that Which? found DAB radio interference with a batch of generic LED bulbs. Has this been reported in the magazine or on Which? Conversation. It would be very interesting to see a comparison with LED bulbs sold by the larger manufacturers. In the recent test of LED bulbs, there was a brief reference to lack of interference on DAB radio.

At present, there are still more users of FM radio than DAB, and one may be affected more than the other, so we really need information about interference (or lack of it) on both bands.

Thanks Sarah. That is encouraging because there are some posts on this and another Conversation about LED bulbs from large manufacturers causing radio interference. The consensus seems to be that the 12 volt bulbs commonly used for downlighters are more of a problem than mains voltage lamps. Perhaps Which? could include these next time a test is planned.

Every time I use my Which? recommended steam cleaner, it shorts the electricity circuit. I then can’t use most of the downstairs sockets, and the electronic key for the garage door won’t work either. Which is a pain when you realise the circuit box is in the garage and to reset the trip switch means opening the door manually, Which I can’t do. From now on I’m going to have to open the garage door before I clean the floors. Why is this happening?

Jill, it sounds like an earth leakage current that trips an ELCB in your fuse box. If it lets you reset the ELCB and then works normally it may be just an excessive current through a capacitor in the machine rather than an actual fault, but I would stop using it and contact the manufacturer.

Hi Jill, that sound’s worrying! Have you considered taking the steam cleaner back to the shop and getting it replaced? Here’s a useful guide on our consumer rights webpage that I’m certain you’ll find handy:


On a further note, you could get in touch with a local and reliable electrician to come take a look at your house’s electrical circuit:


Jill – Your electricity supply has tripped because there is some sort of fault. There is a small risk of electric shock or a fire if you carry on using a faulty appliance. I suggest you take it back to the shop you bought it from.

All this is pretty damning evidence and supports those of us who condemned DAB from the outset. VHF FM was better and after freeing up VHF TV channels, they should have been given over to VHF radio.

It would be interesting to see a full investigation into the interference problem. Are the devices (Steam Mops and LEDs) truly emitting interference at unreasonable levels or is their radio or TV signal too low? My experience is that you need an external aerial for best reception of both TV and radio.

You are right to question reception, Terfar. It is difficult to eliminate all interference, particularly at short range, and if the signal is weak, interference has a much greater effect. I have both an FM loft aerial and a DAB external aerial, though the latter has been rendered redundant thanks to improved signal strength.

I am disappointed that Which? appears to be testing LED bulbs for DAB interference when most users are still on FM. However, I don’t see any reason for condemning DAB radio. Apart from listening to music on Radio 3 on FM, I mainly use DAB radio and would recommend a decent DAB car radio to everyone.

An alternative to decent aerials and dealing with products that cause interference is to use internet radio.

Here is a link to a 2014 survey on digital radio, which indicates that DAB represents about 37% of current use: http://www.rajar.co.uk/docs/news/RAJAR_DataRelease_InfographicQ22014.pdf It is quite clear that we need to retain FM radio and to include FM radio when testing for radio interference.

The target is (or was) to postpone the switchover to digital radio until it is used by at lest 50% of the population and that 90% of the population has coverage, similar to FM radio. Since some areas are covered by FM only and some by DAB only, it makes no sense to phase out FM radio anytime soon.

My experience is that DAB has a higher immunity to interference than DAB, but I do not know if this is generally true.

It would be good to have a Conversation about DAB and FM radio since it had been proposed that the switchover would take place between 2015 and 2019.

Philippa B says:
21 February 2015

We have an ongoing problem using our cordless phones in the back of the house though they are fine in the front. This is a real nuisance as I can’t make a call when in my study next to my wired in (Virginmedia cable) Apple imac and need to refer to stuff on the screen.

It started with ordinary BT landline extensions but the current electric plug cordless system isn’t any good either.

Also fm transistor radio is not good in the back of the house though plug in radios works better.

Does anyone know what this could be and more importantly could any other phone system fix this?

Philippa – All computers will generate some interference, but my mobile phones show now interference next to my 24″ iMac. The easy way to tell if the computer is causing the problem is to shut it down.

The router might be the source of interference, particularly if it is nearby, so try switching this off too.

The cordless system you mention would seem a likely culprit, except that you had the problem beforehand.

If you cannot trace the problem by switching things off, try switching off your mains supply at the consumer unit.

If you have established that the problem is not in your home, it might be something a neighbour is using if their house is attached to yours. If the interference is outside your home you should report the problem. It’s the BBC that investigates such problems on behalf of Ofcom.

I hope you can trace the problem, and do let us know how you get on.

Any radio amateur will tell you that the general level of electromagnetic ‘smog’ has been increasing for many years, to the extent that, sometimes, it becomes impossible to receive any other than very strong signals. Amongst the main contributors are plasma televisions and power line data transmission. It really is time for Which? to take this subject seriously in its reviews. It took many years for pollution to the physical environment to be recognised and for strategies put into place to correct the situation. If steps are not taken now it will be virtually impossible to repeat the clean-up process for the electromagnetic environment and radio reception will then become virtually impossible.

I understand that manufacture of plasma TVs has declined and those manufacturers still producing them are likely to phase them out before long. Unfortunately, power line data transmission is now widely used in the home despite the problems that were obvious from the start.

With so many sources of electromagnetic radiation in the home, is there really any likelihood of addressing the problem, especially considering the demand for wireless technology?