air con or dehumidifier?

[Simon Finnigan]

Hi everyone, The wife normally dries washing in the back room, which means leaving windows wide open to allow the moist air to escape,, and takes quite a while to dry clothes. Because of the hours we work it's difficult to dry clothes outside we don't like tumble driers, so we're looking at some form of dehumidifier for this room, to speed up the drying of clothes.

I've seen that mechanical dehumidifiers that seem up to the job cost about £100 upwards, whereas a portable air conditioner can be had for £150. The windows in the back and living room are identical, so the air conditioner could be used t cool the living room down in the event of a heatwave over the next dew years, which is tempting me to spend the extra money now.

The problem is, I can't find any information online about the relative efficiency of vote types of unit for dehumidifying, which is the main purpose. A dehumidifier tends to have a bucket of some kind for the water to go into, the air con seems to pump the hot moist air outside, leaving cool dry air inside, which would be nice.

Have I misunderstood the differences in how they work and does anyone have any ideas, suggestions or tips as to problems I may face in going for the air con route?

Thanks in advance for your help!

[Fredxx]

Why don't you like tumble driers?

[Simon Finnigan]

Expensive to run, ruin clothes, no space for one, and a dual washing machine and tumble drier is much more prone to break down than a single purpose machine :-)

[funkyoldcortina]

A condensing tumble dryer is basically a dehumidifier with a rotating clothes drum built in...

[Fredxx]

Hmm. A dehumidifier isn't that efficient. It gobbles up 150 to 200 Watts for an awful long time having minimal impact.

If you want to cool the room then a air-con is the way, though the sort you seem to have in mind isn't as efficient as a remote heat-exchanger. It's not going to be very efficient at drying your clothes, and even more expensive to run.

If you want to dry clothes, then a heated airer or a tumble drier is the way to go. A tumble drier may use 2kW for up to an hour to dry your clothes and it's up to you whether you view that as expensive.

Mine has a humidistat so there's no guesswork when it's finished, so overall saving power.

If space is an issue then a combined washer drier is perhaps the first choice.

If it does beak down outside of the guarantee period, then ask for advice here. This is a DIY group after all!!

[Hugh - Was Invisible]

We have an old pinguino portable air con unit.

It can be set to fan only, air conditioning or humidifier.

It collects a little water inside that has to be emptied very occasionally.

[Jethro]

Dunno, the "Candy" dual machine we had went for 14 years, and was still working when we replaced it.

Mind you, I think we used the TD twice in all that time.

[Simon Finnigan]

Ive heard a fair few people say that pulling the moisture out the air makes a big difference to how quickly clothes dry. Like 2-3 l overnight, which is a fair proportion of the water in the clothes.

expensive to run.

It's the effect the heat has on the clothes I dislike - the wife has a lot of stuff that just isn't up to being tumble dried, and I never liked the feeling of my clothes after tumble drying.

saving power.

But I've certainly found the dual use washer/driers to be a lot less reliable, more expensive to buy and not as good at doing either job.

[Fredxx]

I've tried it and it wasn't particularly successful. A dehumidifier left overnight consumes the same or more energy than a tumble drier load.

expensive to run.

As you suggest some clothes aren't best dried in a tumble drier.

I am surprised at your general assertion. I find my tumble dried clothes feel softer, especially in a drier which stops at a chosen moisture level. I hate clothes which have been dried too much, where they are hard and also difficult to iron.

[Andrew Gabriel]

Actually, it's significantly more efficient than a heater for drying things. I have a 400W one in the airing cupboard, and it will dry a load of washing in about an hour. A load of towels and jeans might need 2 hours. However, the humidistat switches it off when done. In a confined space, you may need to add a thermostat to switch it off if the temperature goes over the max allowable ambient for the dehumidifier (30C for my one). I only use it if I want the clothes dried quickly.

The water collected is ideal for the steam iron, as it's distilled. I also occasionally use it for some of my house plants that can't take tap water.

Yep - dehumidifier is much more efficient. (Some commercial tumble driers actually use dehumidifiers.)

[Andrew Gabriel]

Both can be got quite cheaply in end-of-season sales. I bought what turned out to be some very nice 400W dehumidifiers with humidistats for either tank or plumbed-in operation, for £60 each instead of £250, many years ago. They're all still working fine (in different family members' homes, mainly for cloathes drying).

Portable aircon units with the elephant trunk to dangle outside are very inefficient at cooling. The reason is they draw air from inside to cool the condensor before ejecting it out of the elephant trunk, and that requires an equal amount of new (warm) air to be drawn in from outside, so the unit is mostly fighting with itself. A very few have a separate air intake for this, which can be coupled to another elephant trunk (I have one, but I haven't seen one for ages), but they still need properly sealing, and not just dangling out of an open window. Eventually I bought a split unit aircon unit, and that works so mach better, as well as being able to be used for heating as an air-sourced heat pump. Actually, I use it for heating much more than for cooling.

For an aircon unit, the cooling and dehumidifying go hand-in-hand. As a clothes drier, you don't want the cooling, so I don't think that would work too well, certainly nowhere near as well as a dehumidifier which generates heat at the same time.

[chris French]

The real problem with combine machines is that the drum is very small for a drier, so you can't dry that much in it compared to standalone TD.

[NT]

200w dehumidifier run for 8hrs, cycling on 25% of the time =3D 0.4kWh 200w dehumidifier 50% of time & 40w fan 1hr =3D 0.14kWh Using your figures, 2kW TD 1-2hrs =3D 2-4kWh

ore expensive to run.

maybe set the humidistat a bit higher.

NT

[Mike Lane]

Simon Finnigan wrote on Aug 22, 2011:

I've always dried clothes indoors using a dehumidifier. I've found it works best if used in a fairly small enclosed space . I have the dehumidifier installed in my bathroom where I've also got the washing machine - so it's a simple matter to take the clothes from the washing machine, hang them on an inside clothes-line, and set the dehumidifier going. It takes about half a day to dry most clothes - thick heavy things obviously take longer. The dehumidifier raises the temperature by about 2 degrees C, so it leaves the bathroom warm and dry which is a bonus.

[Simon Finnigan]

,

I was in B&Q today looking and they've started having their prices cut, but the dehumidifiers still started at £80 for a simple basic one.

[Simon Finnigan]

iIRC the max load for a drier tends to be half that of the washing side of things, which kind of defeats the point for me.

[Simon Finnigan]

This is what I'm hoping for - the dehumidifier/air con would be much better than the other options. As well as being a lot cheaper than swapping my excellent washing machine for a dual purpose machine.

[Jethro]

When I queried this (I said "how come it will wash 6Kg, but only dry

3 ?") I got a world-weary look from the Mrs, as she said "Of course you can't dry *everything* you wash."

Clearly she never spent 3 years at Uni ....

[Another John]

I'm astonished that nobody has yet mentioned that this topic is discussed, with a cheap and effective solution, in "our" DIY Wiki (thanks to the guys who have put it there):

[Hugh - Was Invisible]

and in my experience the small drum is apt to wrap things up into a damp ball