Electric clothes horse vs tumble drier

[Deleted User]

Using any form of purchased energy to dry your clothes at this time of year is a total waste of money, there is enough latent heat to dry your clothes naturally outdoors or indoors.

Drying clothes in colder weather is a little more challenging but nobody commenting above seems to understand the physics of it.

When your clothes are wet, they contain a specific amount of water - let's just work through an example assuming your washing contains 1 litre of water when the wash cycle has finished.

It takes 0.72kWh to evaporate 1 litre of water from room temperature. Yes, that is the amount of energy whether you hang your clothes outdoors on a sunny day, windy or not,  put them in the tumble drier or on a heated clothes rack - that 1 litre of water needs 0.72kWh to evaporate. Exactly the same amount of energy (2.6MJ) whether the clothes dry in 1 hour or 12 hours.

Where you get that energy from and where it goes is what is important along with how much is wasted in the process.

1. On a summer day, clothes on a rack with no heating, will absorb 0.72kWh from the heat of the room - the room will therefore drop in temperature slightly but that isn't an issue on warm days. 

2. Winter days with the heating on, thermostat set to say 20C, the clothes will absorb 0.72kWh of your room heat. So this means to maintain the exact same 20C temperature in the room, your central heating will need to supply 0.72kWh extra compared to not drying your clothes in that room.

3. Winter day, heated rack, heating on, thermostat set to 20C same as above, 0.72kWh of energy - your clothes will dry quickly due to the heated rack, but exact same energy output to that room is needed provided you keep the room at exact same temperature - this time some of the heat will come from the rack, but total energy provided to that room will be the same. 

4. Winter day, heater rack, heating off. The clothes will absorb 0.72kWh to dry themselves but the rack won't transmit all the heat to the clothes, a lot will go into heating the room instead so it will use much more than 0.72kWh of electricity. Your room will be warmer than when you started which is a waste if you didn't want to heat the room.

5. Unvented heat pump tumble drier - this will "move" 0.72kWh of energy from the ambient room temperature to the water to evaporate it but then will recover most of that energy as it condenses that water again. Running this process will require energy to power the heat pump and tumbler/fan etc which is lost as heat to the room. Typically will use about 30-50% of the amount of energy they "move" but that will be released into the room. So in a heated thermostatically controlled room, it will be more efficient than 2,3, or 4 above. In an unheated room, the excess heat is lost to heating the room so again is wasted.

6. Dehumidifier - similar to 5 above but the energy consumption is harder to control because it isn't a closed loop in the tumble drier, it will dehumidify the whole room. This can be an advantage when your heating is on because it takes less energy to heat a low humidity room to the same temp as it does to heat a high humidity room. 

7. Condensing tumble drier - these will still use 0.72kWh in evaporating the water but a lot more heat is lost from the loop to the room and typically use twice as much energy as a heat pump in the process. Same applied, excess energy is lost to the room, so if it is a thermostatically controlled heated room, the main heating output will drop to compensate so all energy retained, otherwise wasted in an unheated room.

8. Vented tumble drier - most wasteful. Extracts ambient air from the house causing outdoor air to come in, which if colder will cool the house. The heat used to dry the clothes is lost to the outdoors. Pure waste of energy and money - don't use.

Note: If the excess heat energy goes into a thermostatically heated room, then the main heat source will compensate by reducing heat output so nothing is wasted. 

If the excess heat goes into an unheated room or is vented outdoors - this is all wasted because you don't intend to heat the room or the outdoors.

In summary:

1. Spin clothes to the max to extract as much water as possible.
2. Use ambient heat to dry the clothes - ie outdoors or unheated room temp for the cheapest cost.
3. If you must use energy to dry the clothes - close the loop and keep that energy in the house, preferably in a room you are heating anyway rather than an unheated room where the benefit isn't felt.
4. Keep in mind humidity is bad for houses. Ventilation involves allowing outdoor air into the house, which if cold requires energy to heat, so a dehumidifier or heat pump drier will work out more efficient on cold days.
5. The cost of the source of heat is important, using your gas-powered central heating will mostly be cheaper than an electric-powered rack heater.

markin

Its pointless, Just use the dehumidifier and a clothes horse 

[Deleted User]

Hi,

might be ok for your wife's smalls but no good for likes of bedding.

One of these costs nothing to run.

xeny

Use one, and am happy with it. in most weather pointing a fan at it dries clothes about as quickly as turning it on, and uses rather less electricity.

It lives in a spare room which generally has the window at least cracked open so there is some ventilation and that seems not to have resulted in condensation issues.

They will deal with a change of double bedding, but nothing else at the same time.

People who change towels daily surely could find something more interesting to do with the time?

Percypeeved

How about an old-fashioned spin dryer? 2800RPM, approximately 30 watts a cycle or just pennies a spin. Polycotton sheets and synthetic fabrics come out nearly dry, and heavier cotton fabrics take much less time to dry, whether using a tumble dryer or air drying.

Astria

Considering the outside temperatures at the moment I just put all the washing on a clothes horse (including bedding) and leave it 24 hours with the windows open. In the winter when the heating is on I might use a dehumidifier as well on low. There's no need for any kind of expensive electric heating, although I do sometimes use a tumble drier on cool as it does a particularly good job of removing lint and costs approx 0.5 kWh.

SAC2334

Percypeeved said:

How about an old-fashioned spin dryer? 2800RPM, approximately 30 watts a cycle or just pennies a spin. Polycotton sheets and synthetic fabrics come out nearly dry, and heavier cotton fabrics take much less time to dry, whether using a tumble dryer or air drying.

Thanks for that tip, I m onto buying one .That is really a fast spin ! Theres a little used White Knight on sale near me for £45.
New they are over £130 .

.My spin dryer on my AEG washing machine really bangs around unless its perfectly balanced and has a max of 1200 spin .Might be years left in it yet if I don t let it spin 

B0bbyEwing

Alnat1 said:

Can I suggest tumble dryer balls. I use them and they seemed to shorten the drying time so I thought I should prove it. https://www.wilko.com/en-uk/jml-dryer-balls-2-pack/p/0412526

Used our king sized bedding as the test load as it's washed weekly. First week, with balls took 36 mins in tumble dryer, 2nd week, no balls, it took 48 mins. So a 25% time reduction.

We don't have those ones but we do have some material-type balls. Like fluffy things. 

Awesome description I know  

Wonder if they do the same job?

Regards tumble drying, I also wonder whether we just do overkill - oh I'll bang it on for [x-time] that should do, when it may have been dry like 10, 20 minutes earlier.

 SAC2334 said:

neither, not at 45 p per kwh !
I hardly used my tumble dryer when my leccy was 10 p kwh so the tumble dryer is off limits and won t be used again unless in emergency's . 
I m retired now so can pick my day to peg out the washing and even in winter clothes will dry if theres a bit of wind.
Plan B is to use my large rear conservatory 

Would be superb if any of that helped my situation. However

* I'm not retired
* I have no conservatory.

Though I suppose your post will help someone who may be in the same situation as you ... just not the thread starter.

QrizB said:

I've definitely tried that in winter and sometimes ended up with stiff frozen clothes.

Ahh someone with the same experience as me then.

We clearly live in the wrong part of the UK. We need some of that air that these other guys get where the clothes will still dry outside in winter. 

Alnat1

My tumble dryer has a sensor so auto stops when clothes get to requested drying level, can choose ironing dry to wardrobe dry with a few between. When it starts a high number of minutes show and this drops down fast as the sensor works out the "dampness". Once it's dropped down to 20 minutes you know that's the time that's really left. I think most dryers now have this function.

I used to get home from work to the smell of cooked clothes with my old dryer, hubby turned dial round to 120 mins and forgot to keep checking. Also ended up with very tiny or wide t-shirts!

B0bbyEwing

Deleted_User said:

2. Winter days with the heating on, 

Excellent post as per & very helpful. Thanks.

However you're spoiling my next question which I was going to ask once this thread has died a death  

frugalmacdugal said:

Hi,

might be ok for your wife's smalls but no good for likes of bedding.

One of these costs nothing to run.

While not exactly that one we do have one ... and use it.

My wife is just taken in with these news articles whereas I'm the question asker.

Example...

Covid hit - we're all going to die & she's buying £20 face masks.
Russia invades Ukraine - she's already got them knocking our front door down the following week. She had to turn news notifications off.
There's other stuff she sees in the news which I forget now but yeah, I tend to ask questions first before I do anything, especially if it's something in the news. I don't just swallow it straight away.

Astria said:

Considering the outside temperatures at the moment 

I know you went on to talk about in winter time which is fair enough.
but as you weren't the only one to mention this time of year, I felt the need to respond to it & say that I specifically said on page 1 I'm talking about winter/wet time, not summer time. Summer isn't even a question as that's taken care of. The clothes go out on the line & when the line is full, the rest go out on the clothes horse & that goes out in the back garden too.

Summer is sorted.