Washing Machine Load Capacity
Loads of people think buying the biggest capacity they can is a good thing but, maybe it isn't
There's really only three ways that most washing machine manufacturers have attempted to woo people into buying their brand or products, price (obviously), spin speeds and the amount of clothes that the machine can swallow up in one go. Here we look at the validity of the last of the three.
You could be forgiven for believing, as all the marketing tells you this and therefore, it seems to have become conventional wisdom, that a washing machine that can wash more clothes in one load is better than doing two small loads but I would argue that that is not always the case and besides which, there is a price to pay for that facility.
Facts About Washing Machine Load Sizes
According to research carried out for Which Magazine, the average load size in the UK is about 2-2.5kg of clothing per wash load. How is this you ask, when most machines for the past few years have been 6kg loads? Well it's simply down to the fact that, whilst the machine can have 6kg of laundry packed into it, it won't work!
I was recently talking to some boffins in white coats that spend all day long in well lit labs looking at washing machines, they explained that when these measurements are taken that the manufacturers are allowed to have the laundry professionally folded and packed into the drum. I had to stop and wonder how many users of the washers would actually do this. None was the conclusive answer. And this conclusion is only re-enforced after seeing people using washing machines day-to-day in the field, nobody would do it and nor would they want to either.
In most homes, including my own (unless I spot differently), the washing is tossed into the machine in no particular order or with much of any care.
Basically the load ratings seem to be more of a guide as to how big the drum is and not much more.
Of course the problem is of course that if too much clothing is placed into the drum the laundry won't move very well and this will stop the clothes from being cleaned as effectively as they should be. This is classic overloading, although it can also be the cause of other issues as well.
How Larger Capacity Drums Are Possible
Manufacturers are very quick to tell you that their new "whizz bang, electronic washing machine with blue LED's and touch controls" has a 1600rpm spin and a huge 8kg drum meaning that you can wash a duvet or you can do more in one load but they fail totally to tell you the price beyond the in-store ticket cost.
Below is a simple diagram of how machines have evolved. I've tried to show the differences and the actual differences in load capacities.
As you can see the drum size increases internally, but that's actually a part called the outer tank. It is called a "tank" because this is the bit that holds the water in and it wraps all around the "drum", which is the bit you put your clothes into through the door of the washing machine.
Now it's pretty obvious that the outside dimensions of the actual machine don"t change and this is very important.
So how do you fit more in? It's not the Tardis after all, it's a washing machine and it still has to fit in the standard 600mm x 600mm x 850mm space.
Very simple, you increase the size of the outer tank allowing you to increase the drum size and also (and this helps the EU labelling as well through reduced water) you minimise the distance between the two as well, giving a few more millimetres.
The net gain is that you get an extra pair of jeans in, maybe two. But you certainly won't see your clothes swimming about in an ocean as one recent advertising campaign would have you believe.
Example Of A Large Load Washing Machine
The picture below shows a Servis 7Kg load washer dryer, just a typical example of this new breed of washing machine which was snapped by Martin Russell.
As you can clearly see there are quite a few compromises that have had to be made in order to make allowance for the large capacity.
For example, the dryer motor would normally be on top, at the heaters to blow the hot air and here it is mounted at the bottom with an additional belt to drive the dryer fan. A far more unreliable setup we think that requires the additional belt.
You can also see how the motor has had to be mounted at an extreme offset to clear the floor! We suspect the only thing keeping this M9813W washer dryer stable is the fact that there's another motor opposite it.
But what is glaringly apparent is the lack of space between the outer tank (drum) and the actual cabinet itself, which leads to the issues described in this article.
In case you're left wonder what was wrong with this one, well it wasn't really gone into other than the report that "The dryer makes a noise similar to a Harrier jump jet on final approach, a burning smell like Burger King's chimney stack and leaks like the Hoover Dam". And, it was scrap at a mere eighteen months old.
Negative Effects Of Larger Capacity
So we have a larger outer tank, therefore logically, we have less space between the tank and the outer shell of the machine. So we have to control vibration better, how? Well in most cases these days this is done electronically through what they call an Out Of Balance Detector (OOB) or Anti-Balance Control (ABC) which, when it detects any imbalance, will not allow the machine to spin. This simply stops the tank from smacking off the outer casing through excessive vibration.
So spinning single items, or even a few on most, in a modern washing machine... forget it!
But look closely at the diagram and you see another effect as well. The amount of distance that the suspension can travel is also reduced which can lead to more vibration. So, it can actually cause the above problem to be still worse again!
Stick a lot of these machines on poor flooring and you have a recipe for disaster, the washing machine very likely won'¢t spin or it will bounce about all over the place. More often than not the washing machine won't spin and we get a lot of complaints about this on modern washing machines sadly, there's nothing we can do as they are designed to behave that way.
Of course another effect, as shown to the right, of having a small space between the inner drum and outer tank is that if something gets stuck in there that shouldn't there is a far greater chance of damage.
Washing Machine Performance
This is something that came up as we were researching new models for ISE when we learned that, where a capacity over 5Kg was used that the mechanical action of the machine was affected. You can get over this problem with some clever drum design to take it to a 6Kg load and retain the wash results but, beyond that it becomes very difficult.
The following diagram shows the mechanical action of the wash.
What this is showing is how the clothing is "lifted" by the paddles to the top of the drum and then falls back down. This process requires precise control of the drum's speed of rotation as you also have to not be too rough or you can damage the garments and, that there is enough force to carry the clothes to the top in order to fall back. It is this "falling" that slaps the clothes off the drum loosening dirt.
What happens in a large capacity machine is that the clothes cannot often be carried up to the top of the drum as it's too big, so the don't fall back down correctly. The result of this is that the clothes just basically swirl and tumble at the bottom of the drum and do not get correctly washed.
What people that have the machines then report is, poor cleaning results from the washing machine. Troubles is, there's nothing anyone can do about it!
Getting back to the duvets in a washing machine though, we have already seen reports of poor wash results with these from brands that advertise that their super duper huge load washers can clean them and, we've also seen at least one machine trashed washing a duvet. What the marketing guys don't tell you is that there are different types of duvet and the difference are vast, just look at the TOG ratings of blankets let alone anything else and, when they are wet, these things expand, a lot.
Our advice is, if you want your duvet washed and washed properly, get it done professionally as its almost certainly going to be done a lot better than you can do it at home and, if you read the next section, a lot cheaper as well on balance.
Bigger And Bigger Drum Capacity
So now that you know all this the obvious question to ask is, how can we keep getting washing machines with bigger and bigger washing capacities in the same size of cabinet?
It's a good and valid question but not one that is easy to answer without being fairly brutal.
Without going into the whole technical aspects think on this, if you have a direct drive machine with a great big stator on the back how can you make the drum larger? Or, if you are already at the maximum diameter of the washing machines's outer tank, how do you do it?
Well, one way is to make the washing machine door bigger.
Seriously, it works. It works because of the way that load capacity is tested. You are allowed to fill the machine up to the very front lip of the machine and use all the space there. If oyu make the door larger you have more space, in theory. You can also pack the machine solid remember, no space for clothes to move so, in the real world, you'd never achieve anything even remotely close to the advertised load.
The fact that it isn't actually usable space doesn't matter one jot in the tests that determine load capacity.
The kicker is, when you close the door (because it's bigger) the protrusion into the drum space is also larger and you can actually end up with less useable space than if you used a smaller door.
But people do tend to believe the marketing hype with many manufacturers that theirs is bigger. It kind of silly really.
So if we know that these machines don't really take as much as is made out and, we know that the average load size is way under the claimed capacity then why do it?
Simple, marketing. A case of, mine's bigger than yours and people will pay more to get a bigger capacity washing machine or tumble dryer, even though they may never use it.
To explain, if you split your clothes properly into darks and lights at the very least, then in most homes a 6Kg machine is more than adequate. If you need more than that then I'd suggest that you look at a US toploader or a semi-commercial machine as your needs exceed that of a "normal" domestic situation.
Also with large capacity machines, over 6Kg, you have to increase the detergent dosage so that there's enough ingredients to remove calcium from the water and do the job properly, whether you fill the machine to capacity or not. Currently the detergent manufacturers recommend that you use 50% more detergent on a large capacity machine and this could prove costly.
The other gem of information that isn't told to people is that these machines require more water and more electricity for EVERY wash. For example a typical 7Kg load machine will use 15% more electricity and up to 10% more water than a standard 6Kg load machine but, because of the way the EU labeling system works it can still be sold as an "A" rated machine.
Over a year this can add up to an additional 1800 litres of water, up to £73 a year in electricity and upwards of £30 a year on detergent. This is based on the difference between a 6 and 7Kg machine, go larger than a 7Kg load and those figures will only increase, dramatically.
So our suggestion is that if you are looking at a large capacity machine as a way of saving money, think again.
Environmental Impact Of A Larger Drum
As we have demonstrated above the larger capacity machines use more energy, water and detergent to work and, contrary to that, many manufacturers would have us believe that washing more in one go saves more on all counts.
Well, in our opinion it's simply not true, it is merely twisting the story but then, we're all used to spin these days. The fact is that to wash XX Kg of laundry takes YY litres of water and ZZ KWh of electricity and that will be that. There's no magic involved and there's no new technology that has radically altered the laws of physics yet.
The problem here is of course that when you do a smaller wash, which a lot of people do for dyed items and the likes, these machines are massively inefficient and very costly to run.
Is this good for the environment? Short answer is, no, it's not as it uses more resources to work, can lead to more failures or early changes due to poor results and, they cost more to buy and run.
Just as they do with the high spin speeds many manufacturers are using this as a sales tool to get more money out of people for things that, really, you don't need. The annoying thing here is that the cons of the capacity, just as they are with spin speeds, are not being properly explained.
Now, are you really sure you still want that large capacity washing machine?