Do you use electric clothes dryers?

BooJewels · 14 October 2022 at 11:02PM

Apologies @AdamDoubleG that your first post hasn't been replied to, I didn't see it myself until now.

I'm not sure I know the answer as I've never used a tumble drier. I personally use a pulley operated clothes airer below the ceiling in my utility room and that works a treat for me. The only heat source in there is the boiler itself, but I don't know how much heat it actually gives off these days. But my laundry is rarely time-sensitive either. I'm not sure heating on or tumble drier is an easy comparison as the tumble drier is only useful for your laundry, but the heating has other benefits. I've never used a dehumidifier for laundry myself - just never felt the need.

I was coming to post that I put the washing machine on the P110 energy monitor today and my 40°C 'quick wash' took 55 minutes and used around 0.5kWh in total (difficult to tell precisely as it only records consumption in 0.1kWh increments) - including 3 extra spin cycles - they're additional time of course - between 9 and 10 minutes each. The first 0.4kWh was achieved by 19 minutes after getting the water up to temperature. The further sploshing, draining, re-filling, rinsing and spinning only added a further 0.1kWh or so - might be 0.199kWh of course. At worst, at 0.6kWh it would cost around 20p per wash cycle.

I did notice that it didn't hold the laundry in the hot water for long - it had barely got up to temperature (i.e. the monitor showed a drop in power draw) when it sploshed about for a couple of minutes, then dumped the water and started the rinsing process. So next time I'm going to knock the 'quick wash' button off to see what that results in time-wise and energy use and also a non-quick 30°C wash. Maybe I didn't get good results at 30°C because it barely holds it in the hot water for very long on a quick wash. Now things aren't as time-sensitive, I will maybe get better results at lower temp, but for longer.

What was interesting was that I did weigh an item (t-shirt) between each spin, to see how much additional water it got out - I don't know if it's a valid way to determine water content, but it's all I got. I forgot to weigh it dry, so I'll do that when it has dried. After the machine had done it's slow spin at the end of the cycle it weighed 315g, then after each subsequent additional spin > 308g > 303g > 299g. I have always been able to tell that it improves tangibly after the first additional spin, but I'm surprised that it continued - albeit slightly diminishingly - after each of the additional cycles. So if I had 10 similar items in the wash, that's potentially a further 160g water removed - 160ml - a small glassful. it's difficult to quantify how much juice each spin used, but using the average wattage draw v time it took - I think it was about 26Wh on average - so less than a penny per spin. How much does a tumble drier cost to remove/dry 160ml water?

Bendy_House · 15 October 2022 at 8:03AM

Nice investigating, BooJ!

Weighing comparable items like identical T-shirts sounds a pretty perfect way to not only compare how QUICKLY items dry, but HOW dry they actually get with different methods. For instance, if you had a few ID shirts, you could remove one after the normal spin, and leave another in there for a further go; you can then compare them side by side as they're clothes-horsed, or wherever else they go. Eg, weigh them both again after, say, 2 hours, and see if the difference has narrowed, or whether the extra-spin one is still nicely in the lead.

Bendy_House · 15 October 2022 at 8:06AM

I don't think it's any surprise that a quick wash at a low 30o doesn't give great results. Since the heating of the water seems to be the energy 'biggie' in a cycle (tho' 30 is just 'warm', so can't use that much), it makes sense to me to keep the washing thrashing around for a good while more - much better wash for little extra power.

Bendy_House · 15 October 2022 at 8:30AM

I'm still pretty sure that the cheapest way to dry clothes is to do as much as possible without any power, and then finish it off as required.

So, certainly a good spin, since starting with sopping wet ain't practical, and will lead to issues.
Then, hang outside, or the nearest equivalent. Spare room, porch, connie, or garage? Draughty as possible, no heating (it'll be wasted), and clothes as 'aired' as you can. Ie, nicely laid out on a horse or rack, with space for air to move. A fanned, covered, drier could be useful if space is tight, but don't add heat - it just shouldn't be needed, certainly at the early stages. VENT the room, or you WILL have cond issues, AND it won't dry properly! Leave for a day to dry naturally. 2 days if it's clearly of extra benefit, or if the ambient humid is high so drying is slower. By now the clothes should just 'feel' cold and probably 'clamny', but not at all damp or wet - it should have moved on a significant stage.
Then bring the 'orse in to your normal, heated, warmer living area, but don't put on the heating specially - it should dry naturally, and to an additional stage. It shouldn't cause any noticeable cond issues, since the amount of ADDITIONAL moisture it's contributing should be minimal, and also gradual. Give it a day.
Finish by either moving the 'orse close to a heat source, or even on a rad, using a clip-on rack. Or, if you have a warmed airing cupboard - eg hot tank - nicely spaced out in there.

Important points:
ventilate THOROUGHLY - literally as much as you can - in the initial stages where the vast bulk of water is removed.
Judge the time required for each stage - don't just do '2 days here, one there' if it ain't needed. Ie, I'd IMAGINE that a fanned set of clothes in a well ventilated room will be suitable for final airing well within one day, could be just a couple of hours.
When you bring the clothes to the warmed 'livng' area for the 'final', don't force-dry it by turning up the heating or placing them on a rad too soon; you ideally want it to dry at a rate that doesn't contribute a detectable level of extra moisture. It should just dry 'naturally', and the air not be any more humid than caused by 'living'.
A final mega-dry on/near the rads, a few items at a time will get them 'bone', again with no adverse consequences since the actual quant of moisture, and the rate of release is so minor.
Adjust all of the above depending on your house's condition. Eg, if you have an older property that you struggle to heat, and don't ventilate properly 'cos you hate the idea of losing heat that way, and you therefore have cond on your windows and mould in the room corners, then natural drying like this is unlikely to help.

YoungBlueEyes · 15 October 2022 at 9:34AM

Bendy_House said:

<snip>
.......and clothes as 'aired' as you can. Ie, nicely laid out on a horse or rack, with space for air to move.
<snip>
Then bring the 'orse in to your normal, heated, warmer living area, but don't put on the heating specially -

Can't believe this hasn't been suggested before - the govt should be giving out horses left right and centre for clothes drying. Their body heat will do most of the drying work for free!

BooJewels · 15 October 2022 at 9:44AM

Good morning @Bendy_House Out of curiosity, I just weighed the Tshirt again and it's still a bit damp on the thicker bits like seams and neck binding etc., but after 20 hours on my pulley airer it now weighs 230g - so 69g - 69ml of water has already dried from it. I'm pretty flabbergasted that it's actually that much - I guessed what I thought it might be and was expecting around 270-280g. It's at the stage now that if I popped it on the radiator whilst I went in the shower, it would be dry enough to wear. I'll be curious to see how much lighter it is when fully dry.

I'm certainly going to try washing at 40°C without the quick wash - I think reducing the time is just a habit when you're trying to get school uniform and sports kit done after work in an evening. Looking at the power draw yesterday when it was running, I doubt the extra time will add more than 100Wh. Now it's just me and I'm here all day, it doesn't matter how long it takes. I have always been a habitual soaker though - if anything is grubby enough it gets stain treatment and a soak, as required. So for most purposes, a quick wash is good enough - but now I've studied it more carefully, it also seems wasteful. It's also true to say that I've given more thought to my laundry this last week than in the previous 25 years!

Whilst my airer isn't in a room [unheated utility] that I specifically ventilate for the laundry, it's next to the back door and I open that a time or two a day in winter and in summer is often open for several hours - at which time, with warmer air, it would all dry in 24 hours. I've never had a mould or condensation issue in that room - but might do it if was actually heated. My airer works so well for me, that it has to be a spectacular drying day for me to actually peg washing outside in preference.

Bendy_House · 15 October 2022 at 10:00AM

BooJewels said:

Good morning @Bendy_House Out of curiosity, I just weighed the Tshirt again and it's still a bit damp on the thicker bits like seams and neck binding etc., but after 20 hours on my pulley airer it now weighs 230g - so 69g - 69ml of water has already dried from it. I'm pretty flabbergasted that it's actually that much - I guessed what I thought it might be and was expecting around 270-280g. It's at the stage now that if I popped it on the radiator whilst I went in the shower, it would be dry enough to wear. I'll be curious to see how much lighter it is when fully dry.

I'm certainly going to try washing at 40°C without the quick wash - I think reducing the time is just a habit when you're trying to get school uniform and sports kit done after work in an evening. Looking at the power draw yesterday when it was running, I doubt the extra time will add more than 100Wh. Now it's just me and I'm here all day, it doesn't matter how long it takes. I have always been a habitual soaker though - if anything is grubby enough it gets stain treatment and a soak, as required. So for most purposes, a quick wash is good enough - but now I've studied it more carefully, it also seems wasteful. It's also true to say that I've given more thought to my laundry this last week than in the previous 25 years!

Whilst my airer isn't in a room [unheated utility] that I specifically ventilate for the laundry, it's next to the back door and I open that a time or two a day in winter and in summer is often open for several hours - at which time, with warmer air, it would all dry in 24 hours. I've never had a mould or condensation issue in that room - but might do it if was actually heated. My airer works so well for me, that it has to be a spectacular drying day for me to actually peg washing outside in preference.

Sounds good.

Instead of 40oC and longer, why not stick with 30oC and a longer - normal - wash? I think the biggie will be the heating of the water, and there is a LARGE difference betwixt 30 and 40o - assuming the incoming mains is at, say, 10-ish degrees, that's the difference between a 20o raise and 30o. Which is - brings out calculator - quite a bit more.

Adding heat to your utility room won't cause mould or cond, but not ventilating it almost certainly will. Ie, if you 'warmed' it a bit but shut off all the external doors and windows, then it would likely suffer - if it was cooler than the attached rooms.

Anyhoo, you seem to have yer 'aundry sorted :-)

getmore4less · 15 October 2022 at 10:13AM

Nice job BJ. might try the weighing
I have the P110 connected to Home assistant(HA) as the Tapo app is rubbish.

There is also a node-red version I have not tried and I think that is easier to set up than HA.

I suspect the biggest savings from the wash side will come from full washes.
This was one of our full load** eco cotton 60c with extra rinse
current use and cumulative.

Image: https://us-noi.v-cdn.net/6031891/uploads/editor/km/sxnefnp4fr32.png

Image: https://us-noi.v-cdn.net/6031891/uploads/editor/8p/zue1oofhu8jx.png

key data points on the cumulative(Kwh I can zoom in for 1w resolution)
0.237 start
0.247 start of heating
0.746 end of heating
1.077 end of cycle

0.499 to heat
0.840 full cycle

the follow up drying(HP dryer)

Image: https://us-noi.v-cdn.net/6031891/uploads/editor/ah/fivz4gbq2kbw.png

Image: https://us-noi.v-cdn.net/6031891/uploads/editor/6x/dm6rhtndnq1g.png

key data points
2.538 Start
3.625 end of dry
3.639 end of anti crease cycles

1.087 to dry

1.927 total at £0.3506 £67p to wash and dry I do about 12 of these washes a year so rounding up say £10.

Someone has raised an issue that the p110 under reads compared to one of their other energy monitors.
A potential problem is looking for accurate costs.
Less of a problem(as long as they are consistent) if looking to compare options.

** 8kg rated, full as in I stuffed the drum but still only about 5.5kg of underwear and a few other bit that we like to do on 60c

BooJewels · 16 October 2022 at 10:21AM

I just wanted to acknowledge your post here @getmore4less - I did reply in another thread, but don't want you to think I was blanking your further detail here. I just don't understand why the Tapo app doesn't go at least 1 more decimal place in their numbers, it would significantly increase its usefulness - the data is clearly there. I did notice this morning on the one on my freezer, where I've had two days both recorded as 0.5kWh - that the length of the column varies - one was clearly nearer 500Wh and the other nearer 600Wh - so it is already making the distinction - but far too subtle to be very useful to users.

Just an update on the wet t-shirt - as it were! I weighed it this morning and I consider it totally dry now (42 hours, was probably dry enough last night) - it's ended up at 229g. That means after the first spin it still contained 86g water - 86ml - that's half a glassful - astonishing. So I spun an additional 16ml out of it and 70ml air dried out.

I did look at how Which? conduct their tumble dryer tests and they do in fact weigh items as their test for dryness. They do each item in a batch before - and at different stages - as a measure of how evenly a dryer gets a load dry too. So it is seemingly a legitimate test method.

Bendy_House · 16 October 2022 at 1:38PM

So your extra-spin 'only' spun out an additional 16ml? Was it worth it, I wonder?

Anyhoo, my own wee experiment, just carried oot - I don't want you to think I'm leaving all the graft to others:

I called in at the local village library - a bus stop - and swapped some books. This is a small, stone-built (to look nice), shelter, around 4' deep and 8' wide, and with a ~5' opening in one side. Rough book shelves placed against each end, and bench still in t'middle. Last night it piddled down. Pavement still wet. The day before was very drizzly - dreicht.

The books therein are BONE dry, with nary a wrinkle in a single page. 'Cos it's ventilated

Do you use electric clothes dryers?

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