Washing machine spin speed efficiency figures and drying costs

Efficiency Here are some interesting figures (from an tumble dryer user manual) which give us an insight into the effectiveness of faster spin speeds . The figures are based on a 6kg capacity drum size and an efficient condenser dryer and show the residual dampness in laundry (cottons) after being spun at various speeds.

They also (much more interestingly) compare the difference in energy that’s required to tumble dry the laundry after spinning it at at say 1200 rpm compared with if it was spun at 1000 rpm or 1400 rpm.

Results would vary between different washing machines and tumble dryers, but they do give an accurate representation of the differences between the efficiency of different spin speeds, which I suspect is much less than most people are likely to expect, and the main point of this article.

Spin Speed Residual Dampness Energy Used to Tumble Dry
800 70% 4 kWh
1000 60% 3.7 kWh
1200 53% 3.3 kWh
1400 50% 3.1 kWh
1800 42% 2.6 kWh

(based on a modern A rated condenser tumble dryer)

These figures imply there is little advantage to paying much more for a 1400 spin washing machine over a 1200 spin washing machine, which I’ve seen as high as £50 more. These figures show that the difference in dryness between the two after spinning cottons is just 3% and it would cost only .2 of a kWh extra to tumble dry cottons spun at 1200 instead of 1400 (roughly 3 pence – NOTE: This calculation was done before all the recent electricity price rises of late 2008). Most other fabrics would have the same water extraction regardless of the washing machine’s spin speed because only cottons are spun at the top speeds.

Electricity charges can vary quite a lot these days but on the UK Power electricity running cost calculator the average cost per kWh is set at 10 pence so I’ll use that figure. That means drying a load of cottons spun at 1200 would use 3.3kwh in electricity, 3.3 x 10p = 33 pence . If using a 1400 spin washing machine which costs up to £50 more to buy, it would cost (3.1 kWh x 10p) 31 pence to tumble dry – a mere 2 pence cheaper. You would need to tumble dry such a load 2,500 times to recoup the extra cost in buying the 1400 spin washer if you paid £50 more for it.

Spin speeds are just marketing tools which work because people believe faster is better, and “better” is worth paying more for

Washing machine manufacturers have long since used faster spin speeds as a way to increase sales and command higher prices, but the difference between an 1100 spin speed and a 1200 spin, or a 1200 and 1300 and even 1400 are pretty negligible and mostly psychological. To make a significant difference in the amount of water extracted you have to have much bigger jumps than one to two hundred revolutions per minute.

Why does this matter?

Slower spin speeds mean –

  • Cheaper washing machines
  • Quieter washing machines
  • More stable washing machines
  • Longer lasting washing machines because there’s less wear and tear on the bearings, motor, carbon brushes, suspension etc.*
  • Gentler on laundry

* The point about longer lasting washing machines has been somewhat diminished by the throwaway washing machine problem afflicting the majority of washing machines these days. This is because the price of parts is often extortionately high, which makes many of them artificially uneconomical to repair and prevents them lasting any where near as long as they would otherwise last.

What about 1800rpm?

It’s only when you jump from a 1200 spin washing machine (the current most common speed) to 1800 rpm that you see a more tangible benefit. If comparing the costs of tumble drying after spinning at 1800 rather than 1200 then it would use 2.6 kWh instead of 3.3 kWh. That equates (using the 10p per kWh figure) to 26 pence instead of 33 pence – a saving of 7p. However, an 1800 spin washing machine could easily cost £100 more than a 1200 spin. This would mean someone tumble drying 2 or 3 loads a week would take about 9 years to get a £100 premium purchase back. You should also factor in the fact that an 1800 spin washing machine may be subject to more wear and tear because of the extra speeds involved.

Of course this argument is based on tumble drying laundry. If not tumble drying then the only difference is that it will take a bit longer to dry on the line or in the spare room next to the radiator but at no extra cost. In this scenario the cost issue is replaced by a convenience issue, which for some will be negligible though for others it could be more significant if having laundry drying in the house is inconvenient.

What about the argument that using less electricity is better for the environment?

Save-the-earth That’s a fair point. From an environmental point of view it is better that we all pay £100 more for a washing machine and use less electricity if tumble drying – even if the electricity saved is a fraction of the extra costs buying the faster spinning washer. This is a very different argument to the personal economic considerations covered above and is based on the premise that regardless of the cost to the consumer, the less electricity we use the better.

However, as with many environmental arguments, the whole picture needs to be taken into account and all too often it isn’t. If faster spinning washing machines aren’t built to a high enough standard, and break down more often, or just don’t last as long, then the whole environmental benefit is compromised and the scales could even tip the other way.

Many of the most common washing machines are not made to a high enough build quality to cope with very fast spin speeds. They can be noisy, bounce around too much, refuse to spin many loads at full speed because of over-protective and less sophisticated out of balance systems, and parts can wear out or fail quicker and more frequently.

Summary

Conclusions For the average person buying an averagely built washing machine, 1200 should be the best compromise between drying efficiency and cost, noise, stability and wear and tear. The figures above show that a 1400 spin washer doesn’t get that much more water out. I wouldn’t say avoid a 1400 but you would need to decide how much extra you are paying for the extra 200 rpm and if the extra cost is worth it. If buying a cheap washing machine, 1600 is way too fast in my opinion because they aren’t built any better than the 1000 spin versions they used to make. Maybe even 1400 is too fast for some washing machines these days. (related: Washing machines exploding – what’s going on?)

If you use a tumble dryer excessively it may be worth considering a higher spin speed but again, the figures show that you may need to jump to an 1800 spin to get a significant difference, and currently an 1800 spin is likely to cost so much more it’s debatable whether you will save much money at the end of the day unless you tumble dry all the time. It will still save some drying time though.

At the end of the day, as is often the case, trying to look at the bigger picture is complex and there are many variables that make it impossible to advise a common best tactic. The main thing is to not get carried away thinking faster is definitely better and ask why manufacturers make washing machines that spin at so many different top spins when surely there has to be an optimum that should mean all washers should spin at the same ideal spin speed. It costs virtually nothing extra to make a washing machine spin at a top spin of 1000, 1200 or 1400, with spin speeds often set artificially by simply configuring the same pcb differently.

Related:


The arguments in this article are based on electricity charges being at certain (quoted) rates. If electricity charges increase significantly it may affect the argument. At the end of the day if you can follow the argument and factor in the amount you are paying for your electricity you can decide for yourself.

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Comments

  1. avatar Donna Pease says:

    This has been brilliant information. I ordered a 1200 rpm machine and was worried about the dryness of the clothes and was going to cancel it and pay an extra £200 for the 1400rpm machine. After reading this I am definately not going to waste my money !!! Thank you, fantastic information.

  2. avatar scott crowther says:

    I have to echo the comments left by Donna above. Your site has been fabulous research info and I know exactly what i am looking for in my price range now. thanks.

  3. Many thanks.

  4. avatar Oliver Shaw says:

    My washing machine is an 800rpm spin and is perfectly adequate. I had a 1300rpm previous to this and the laundry felt virtually no drier even the towels, and the tumble drying times are just about the same give or take 5 minutes! So extra fast speed would be a waste of time IMO.

    The drier is a Crosslee White Knight “A” Class if you are wondering, not used in the 8 hour mode though, but still cheaper to run than a normal drier.

    HTH,

    Oliver.

  5. avatar Washerhelp says:

    Some years back we were using a Hoover 1300 condenser washer dryer. I can’t remember how it came about but we swapped it for a Hotpoint washer dryer which was much newer as I’d somehow acquire it for nothing. I hadn’t realised it was only an 800 spin. However, Mrs. Washerhelp never complained once despite the fact that her old one spun 500 RPM faster.

    You can trust me when I say she would have been more than happy to complain if she had found her washing was coming out much wetter.

    I do personally believe that 1200 RPM for cottons is probably an optimum spin, everything else can be spun at 800 rpm perfectly adequately and with less wear and tear on the laundry and washing machine. There is nowhere near the difference in real-world results that manufacturers would have people believe.

    I’ve maintained for years that spin speeds are merely a marketing tool, and that the slow evolution of an extra 100 revs at a time mimics the same ridiculous managed-evolution of the good old bladed shavers. For years all shavers had just one blade, then it was “discovered” that two blades shaved even better. Two blades ruled until it was “discovered” that three is even better. Then miraculously someone discovered that four is even better still. Then someone launched a 5 bladed razor and so on.. According to research I found, the single blade razor dominated for 70 years, the twin blade shaver lasted 27 years and the triple lasted 5 years – does it really take all this time to discover an extra blade is better? Or do they just introduce them every so often to revitalise the market?

    It’s pure marketing designed to stimulate new sales and get one up on competition. I don’t believe shaver manufacturers couldn’t discover the optimum blades needed for the best shave and stick to it and I can’t believe washing machine manufacturers don’t know which is the optimum spin speed for cottons and then make all their machines use it. The only reason for not doing so – bearing in mind it costs virtually nothing extra to make a washer spin faster and many are actually deliberately made to spin slower using resistors – is to be able to offer a perceived extra value feature people believe is worth paying more for.

  6. thanks for explaining this to the uneducated/uninitiated. My machine broke yesterday. With a family of 6 there’ll be a new washing machine in tonight (machine has probably reached its life span) – you just saved me at least £50.

  7. If the intention is to make clothes drier after spinning, why not use an old fashioned spin dryer, as they would spin clothes at about 2800 rpm! Maybe faster? Then put the clothes into a tumble dryer and see how quick they would dry.

    I’m sure the old spin dryers (and the spinners in twin tubs) had faster spin speeds because the drum is mounted vertically? I wonder why washing machines or washer dryers don’t spin as fast as the old spin dryers? I know some launderettes have a spin dryer which customers use after the clothes have been spun in the washing machine!

  8. The spin dryers used very fast but small motors mounted very close to the drum pulley via a very small belt. They could run at high speeds but couldn’t turn a heavy drum full of wet laundry. They had very small gear/pulley ratios so less speed was lost between the spinning motor and the pulley it was turning.

    Front loading drums needed a bigger pulley to reduce the strain on the motor when turning large wet loads full of water and it had to be connected by a much larger belt. Both of which means a lot of speed is lost between the rate of the revolving motor and the subsequent revolving drum. The motor on a front loading washing machine probably spins at similar speeds to the old twin tub, it’s the gearing that results in lower drum speeds.

  9. avatar Washer and Dryer Sale says:

    This is a great post. Everyone should read this before they go out and buy a new dryer or set. In other words don’t get duped by the slick salesman trying to upsell you on the faster spin cycles. As you mentioned you would have to do 2500 loads of laundry to recoup that expense. Your dryer will more than likely be broke down and gone by that time.

  10. avatar john scott says:

    This is a very interesting topic . I have lived in the US for about 15 years, and work on commercial dishwashers in Hospitals/ restaurants etc. Because of the high temps that are required to sanitize dishes , many of the built in features are purely safety related, and have little to do with the washing side of things. Over the years manufacturers have moved from mechanical sliding rod type of safety interlocks, (to prevent doors being accidentally opened during use and scalding the operator) to magnetically operated reed switch interlocks , that provide the same protection to the user, but at a considerably , cheaper manufacturing cost. The down side of course is that the overall reliability of the magnetic interlock system is actually way worse, it wont stand up to the slime and grease that gets all over it. and the end result is a less reliable product. The cost to the customer is higher , and they get a less reliable product.
    As you say in your blogs, it is all down to marketing and trying to keep the market share, only the customer suffers.

  11. l have an ancient 1957 “ACME” spin drier.This is very much overengineered and weighs a ton,but it gets out FAR more water than any automatic washer will.lt doesn’t surprise me that many new machines fail prematurely,they’re not made to last and parts as you say are extortionately priced.Hardly a very “green” way of carrying on!So they get dumped and replaced by more rubbish build machines,which will also go phut.then the idiots in charge have the front to complain about where’s all this scrap going to go!Madness.

  12. Very good point River.
    Maybe all washing machines would last longer – even the cheap and nasty ones – if people used the slowest spin speed or choose not to have a final spin, if there’s that option. Then put the washing straight into a spin dryer for just 4 minutes. Now the washing will be virtually dry and that would save a fortune on tumble drying costs!

    It’s a matter of having the space for a spin dryer and the extra room needed to collect the water if the spin dryer doesn’t have a pump.

    There is a blog section on the White Goods Help website about the poor quality of modern washing machines. Here’s the link to it:

    Why don’t most modern washing machines last very long?

  13. Why didnt you simply weigh the test towels as they came out of the various spin cycles? You only needed one towel to do this.

  14. Hello doh: I think that’s how people like Which? do it, but I think you would need very sophisticated weighing equipment to measure the difference in weight between two items spun at different speeds. As my article describes, there is very little difference in the amount of water extracted when spinning just a few hundred revolutions per minute so I don’t think I would have been able to detect the difference in weight without very sensitive equipment.

  15. avatar James P says:

    I think doh has a point. Digital kitchen scales can usually resolve to the nearest gram, and even the old-fashioned balance type are pretty sensitive – far more so than the spring/dial variety used in the intervening 50 years!

    Checking the rpm might be an idea, though. I wouldn’t be at all surprised to discover that it only applies to empty drums and well run-in motors…

  16. A related tip: if you have a control to select the spin speed, you might as well spin at a slow speed if it’s a sunny day and you’re going to dry your washing outside. I check the forecast for a sunny day, do my washing then, and only need to spin at 600 rpm. Our machine’s fastest spin speed rarely gets used during the summer.

  17. avatar James P says:

    But why not spin at full speed? It uses little electricity and the wet load will have been reduced by the slower spinning beforehand. I understand if you’re trying to conserve brushes and bearings, although these should be designed for the job!

  18. Hello James P and welcome: I don’t think measuring this difference with scales would produce helpful results. For example, if it was measured and I came up with results that showed an extra 2 grams of water were extracted on a particular spin it wouldn’t really mean anything to me. I wouldn’t have a clue how that affected anything other than it definitely got more water out than a slower spin.

    The main idea of my article is to put any differences into a useful context, such as how much quicker the laundry dried on the washing line or more importantly in a tumble dryer and is extracting “more” water always better per se?

    One of my major points was that, let’s say a really fast spin speed got a cupful of extra water out. Does that matter enough to pay £70 more for the machine, suffer extra wear and tear, noise – maybe even more than a 12 month reduction in lifespan – or do we need to arrive at an optimum spin speed and be happy with that? That’s the last thing manufacturer’s would want though :-)

    I think Chris was building on the point that I made in my article. Spinning very fast, especially with many modern washing machine’s being poorly constructed has hidden cost – if drying on the line you can spin slower, reducing the stresses strain and wear on the washing machine helping to increase its lifespan. The cost would only be extra time on the line. It’s not for everyone but it does make sense if you are prepared to do it.

  19. My AEG has performed perfectly for 8 years with an 1800 rpm spin – the max speed lasts for over 1.5 minutes and a full load of cotton requires 40mins in the dryer max. It’s less noisy than cheapo Hotpoint crap and came with a 10 year guarantee. The thing is built like a Sherman tank – no plastic anywhere !

    .. and another thought, what’s all this about wear and tear? If a car promises 130 mph then you expect it to go at 130 mph with little effort. If it’s sold as fast and you pay for that option then it should be able to acomplish the specification – unless of course it’s an advertising con! ie the cheapo brands

  20. Hello Mike: It sounds like your AEG is one of the last to be made that way. Current AEG washing machines are all plastic and hardly any better made than an averagely decent machine. Many modern washing machines spin much faster than they are built to properly endure, with poor quality suspension and out of balance software as well as poor design. It’s mostly about selling features now, by making them spin faster they can charge a lot more but they don’t build the motor or other components any better than their slowest spinning machines.

  21. The drying costs noted above would, generally, be nearer 50p now. Which? uses a figure of 14.5p per kWh for its running-cost calculations as at this date, as opposed to the 10p quoted when this article was written – so it seems appropriate for us to (particularly as Which? model reviews are often mentioned on this site). We all know that electricity prices are only only going in one direction (!) – so running cost / efficiency issues are increasingly significant, I suggest, in model choice – including spin speed / water extraction efficiency (particularly if not line-drying but using a dryer…) If you manage to line-dry most of the time, this matters proportionately less, of course…

    There seem to be virtually no 1800 spin-speed machines on the market, but, other things being equal, I’d pay more – how much more? – for the fastest available spin. My current 1200-spin Bosch will be replaced by at least a 1600- next time.

    In order to be ‘green’, and to reduce electricity consumption, I line-dry when weather permits (though I use the dryer for 10 mins after line drying to soften and remove lint). But winter means more dryer use.

  22. PS As per the above calculations, the difference between a 1200- and 1800-spin speed would now be 10p per dryer-load. At three loads per week for a year, this is £16. The faster dry may be desirable, too, but this may be offset by additional wear-and-tear on the machine. Still, that £16 will no-dount soon be £20 – and that would certainly make an additional £100 for the 1800 worth it, I suggest. If you manage, as we hope, to get 10 years out of your machine, that’s £200 over its lifetime as opposed to the 1200.

  23. Thanks for your contribution Marcus. Unfortunately the official average life of a modern washing machine is a mere 7 years. Also, electricity costs have increased but drying costs may have decreased significantly too for many dryers as they have become more efficient. My AEG dryer has a fridge-type compressor in it which stores heat and re-uses it.

    I think the 1800 spins may have died out because manufacturer’s realised their current build quality wasn’t good enough to cope. We are already experiencing some washing machines apparently not coping with fast spins (Washing machines exploding: What’s going on?)

  24. Cheapo Hotpoints? I had two, the first one we bought 2nd hand and it lasted us over 5 years, the 2nd one went like a trojan through two babies using washable nappies and only needed the brushes changing once after 10 years. I won’t buy anything else!
    Excellent site and useful info about the spin speeds. Thanks

  25. I currently have a 1600rpm washer. Clothes feel drier and weigh less compared to my mums 1200rpm washer (both Zanussi Jetsystems). Hers is 10yrs old, mine is 18months. I’m now wary of mine not lasting as long, having said that my dad has the predecessor to mine which is also 1600rpm and is now 6yrs old with no signs of packing in. All are heavily used.
    I myself took out an insurance plan as I’d rather repair it than bin it.
    I did read somewhere that the diameter of a drum has an effect on spin speed, something like a big diameter drum spinning at 1600 actually spins at a slower speed. Is this true?

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