Tumble dryer - energy efficiency

Sep 02, 2014 27 Replies

Is a new tumble dryer likely to be more efficient and offer much of a cost saving as compared to the 25+ year old one that I have now?



The dryer lives in my detached garage so there is minimal benefit from any heat that it give out.



Certainly a feature to switch the drier off automatically when the clothes are dry would be a benefit.



The main benefit would be having a bigger diameter drum. It more or less avoids the necessity to iron most items if you take the clothes out whilst still warm she tells me. A warning buzzer to tell you it has finished is a great help.

Heat pump type probably would, but up front cost is steep and depending on usage you may not see the payback.

Worked out that ours needs to last 4 years on our usage pattern to break even on purchase price+kWh consumed compared to a non-heat pump type. Just as well it came with a five year warranty ;) :)

Don't worry, the cost of electricity will rise, you will et your money back before that. Best of all is "rotary dryer". (Bits of string on a pole) Zero energy cost.

But a problem when it rains when nobody is in. Brian

You can buy a rotary line with a waterproof canopy. They are sold under the name Rotaire Dryline. We might get one if our aged rotary dryer pegs out before we do. The resident sewer refuses to contemplate making a DIY cover in the meantime.

Better than that is rotary airer on a dynamo. Generate electricity from the washing twirling round.

Owain

Well yes, we have one of those as well but it's not always practical to use it.

Ooh, didn't know that was a thing :) Swmbo might be interested in us procuring one of those...

I also put a value on my time.

Just hang them in the wardrobe and use a fan or dehumidifier to dry them in situ.

NT

You don't have to stand there watching it.

ROFL! We use our rotary dryer as much as possible. Everything smells better after a good blow outdoors.

I imagine that the newer ones condense the water vapour and recover the energy (the latent heat) that the older ones used to blow out as vapourised water.

If they DO work like that then they must have a condensate drain pipe.

Robert

Or a dehumidifier plus fan in a larger space, works great and very efficient.

They cycle the warm moist air through an alloy casting, which has some cold water from the mains running round the outside. That condenses the moisture from the circulated air, which is then discharged into the bottom and pumped out.

That sounds like a washer dryer.

My condensing tumble dryer has no mains water attached to it. It just uses the cool air in the room to cool the saturated air.

Yes, its a washer dryer, but I wouldn't expect the room air to be cool enough to condense effectively, so assumed the must either use cold water, or have a small chilling system.

That is why condensing tumble dryers aren't very efficient. At least they warm the room in winter times.

I would have thought using cold water to aid condensing would have been an option, but not seen one outside of a washer dryer.

Ones using heat pumps certainly look interesting, but reviews suggest they are very slow, and I don't like the idea of extended tumbling on clothes resulting in accelerated wear.

Our heat pump one is significantly quicker than the LG washer dryer we had, though that might say more about that.. :) As a guide, the last load we dried, just now a cotton double bed set, (bottom sheet, duvet cover, 4x pillowcases) a pair of jeans and a couple of bath towels) took 2 hours to be totally dry. Admittedly they had been spun at 1600rpm so they weren't "wringing" wet. Synthetics dry much quicker and there are various options of "how dry" in the menu. How that compares to a conventional stand-alone condenser model, I don't know. Downside is that it still has a reservoir that needs to be emptied, and no facility to plumb it to a drain :(

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