I'd have thought the MVHR was an obvious choice?

We use a single-room MHRV through the bathroom wall. Works well for us. Practically inaudible in normal trickle mode. In boost (which is automatic, on a humidistat), it's just like any other extractor fan.

http://www.earth.org.uk/MHRV-mechanical-heat-recovery-ventilation.html

Rgds

Damon

Mine? Retrofit. The building is 60s timber frame council.

Note that we fitted another MHRV (different model) in the kitchen. (My sone said a few days ago, words to the effect of "we have a fan in here?").

Rgds

Damon

Posted By: LFWe use a dessicant type dehumidifier in 50s house
It warms the room. Colder spots where it is single brick above windows where the roof overhang is.
We had humidistat fan with no heat recovery before and mould was a lot worse.
It works well for drying washing drying which was main purpose. About 4 hours per load.


About 300 W on low but does not run long after showers and we open windows when there is dry air outside and not in heating season.

Thanks Lee,
I've been looking for a while now, and the problem, for much of the time isn't too great. However, obviously when the CH is on full blast, in the bathroom and the family are bathing and showering the humidity rockets. My first reaction was MHVR. I can't install a through the wall single room device, it's just not practicable. Therefore it would have to be a small loft mount unit, with extract in the bathroom and input into an adjacent bedroom, ( because of loft access).
Then I got to thinking of a small wall mount IP rated dehumidifier above the bathroom door, so out of the way, with a control switch outside. I thought this may be a better solution than MHVR as it wouldn't be used continuously, only after bathing sessions etc.
My research suggested that for my planned intermittent usage a refrigerant/compressor type would be better, although with a potential noise issue. I was interested therefore that your dessicant type works well, and with the bonus washing drying too, I assume it's freestanding.
I'm still unsure though, hence the original question.

Owlman,

Warmth helps as radiators are not often on and the faster the walls are dry, less chance for mould to grow.
We have minimum of 4 showers and 1 bath per day between children (long showers) and ourselves ... all through the day. (The bath is filled everytime despite my describing the effects on the planet, many times !)

Extraction and squeegying the walls may be fine with less "wettings" going on.

We have - EcoAir DD122 Simple Desiccant Dehumidifier, 7 L is what we have. about £140 18 months ago. It has a mechanical knob that sets dryness and we have a temperature and humidity battery unit near by. It is small, less than a carry on bag.
We had same brand more complex control one that failed on electronics and is in loft as a spare. Problem was on the controller not mechanical. It was about 2 years old when it failed.

Gets to about 27/28 C when running for a while, Want to see about 50 to 60 % RH.
This has reduced the mould in bathroom and it takes a lot longer for it to come back but getting washing drying out of the rest of the house is the big win as we were having issues in other rooms.

Washing goes outside whenever possible.

Sits a bit away from the bath/shower. We turn it on high for drying washing for first period and then turn it down when it is been on for an hour our too. I think I checked and it is less than tumble drier but takes about 4 hours.
I think it is 700 W on high mode.

Drain every few days when it working but you can plumb them in. It is smaller than compressor based units and we do not find noise an issue but I have not measured.

In future I will put at high level and have it plumbed into a drain. There is more moisture at high level to "get at" and it will work faster and run shorter I time I think. Filter on it gets vacuumed ever couple of weeks to clean it.

Some years ago, I acquired a low cost portable single room air con unit. I ran it "backwards" such that the air that was dried and cooled was pushed outside and the hot exhaust was vented into the room rather than outside as you would when doing air cooling. You got more heat out than electricity in by a factor of 2 to 3.
The fan broke and then again when I replaced it, so I gave up on this.

Thanks Lee, thanks Green Paddy, this is the one I'd looked at:-

https://www.ecoair.org/DCW10-Simple.html

It fit's the bill but by comparison a little bit pricey at £260, and with one or two negative feedback comments regarding noise. I guess the IP rating pushes the price up.

Yes, it's a refrigerant/compressor type which are inherently louder than the dessicant ones, but like you indicate possibly only used for a relatively short time after bathing. It's this potential on/off usage pattern that steered me toward dehumidifiers in the first place as opposed to single room MHRV.