Many people want to know if it is better to buy a separate washing machine and tumble dryer or a combined washer dryer. Separate appliances are definitely best. A combined washer and dryer will always be a compromise as explained in this article, but they wouldn’t exist if they didn’t have good reason to exist.
Separate Washing Machine & Tumble Dryer is Best
Washing and tumble drying are two totally separate jobs, which need different sized drums. To wash laundry the clothes need to rub against each other so a washing machine's drum size is designed for this to happen. But to tumble dry clothes they need plenty of space to be able to open up and fall through the hot air. This is why a tumble dryer has a much larger drum than a washing machine.
Even though these days it's possible to buy washing machines with really large drums you still need to have less laundry in to tumble dry than the washing machine is capable of washing, usually around half as much. No matter how big washing machine drums get they’ll always be able to wash a lot more than they can tumble dry so you’ll always have to stop the machine and take some out to tumble dry.
With separate appliances you can be drying one load whilst washing a second, which will save a lot of time. Also, because the workload is shared they do less work individually (eg. each has their own motor instead of one motor doing all the work) so they should break down less as well as last longer.
How do washer dryers work?
Combined washer-dryers are just normal washing machines with a few bits added on. On the top of the tub is a metal housing with an extra heating element and a fan to blow the heat into the drum. Washer dryers are condenser dryers now so the hot steam created during the drying cycle is blown into a plastic chamber. This chamber has a slow trickle of cold water running through it so the steam condenses immediately into water, which is then pumped away by the main pump.
They have exactly the same sized drum as a normal washing machine, so with a full load inside, in order to get the clothes to fall through the hot air you just have to take some of the washing out first. This is where the inevitable compromise lies (as with most thing's designed to do more than one job). If you are only washing a small load anyway then you can allow the washer dryer to continue onto tumble dry straight after the final spin, but of course you would have to wait until they are finished drying (which takes longer on a washer dryer) until you can start washing a second load.
Bearing all this in mind, washing and tumble drying a full load of towels or sheets, where you would need to remove up to half the load after the main wash and then tumble dry in two separate loads, is going to take several hours.
Are washer dryers less reliable than a washing machine?
They should be, they have more parts and do more work, to expect different is unrealistic. But they have less parts than a separate washing machine and tumble dryer. So are they less reliable than a separate washer and tumble dryer combined? – That is a much fairer question. According to reliability reports washer dryers do break down more than washing machines, but they have to surely? The only way they could not break down more is if all the dryer parts were so amazing they never failed.
No one seems to have tested if the tumble dryer section on a washer dryer breaks down more than – a tumble dryer, or whether they break down any more than a separate washing machine and a tumble dryer. This is relevant to anyone thinking of buying a washer dryer instead of a washing machine and a separate tumble dryer.
For all we know, a washer dryer may not on average break down any more than the combined separate machines together. My feeling, to be fair, is that they probably do, but not excessively so. Reliability reports do appear to unfairly compare a single machine doing two jobs with a machine doing only one.
What if the dryer part of a washer-dryer breaks down?
There is a common belief that if you have a washer dryer and it breaks down you lose two machines. But logically, if the washing machine part breaks down, what use is a tumble dryer anyway even if you had a separate one? And conversely, if the tumble drying section breaks down on a washer dryer you still have the washing machine working. It can happen, but mostly if a dryer section part fails, it doesn’t usually stop the washing machine from working.
Full summary of the main points of this article
I wanted to create a concise summary of the points in this article but there wasn’t room so I’ve put the summary here – Pros & Cons of washer dryer v separate