Desiccant or Refigerant Dehumidifier - Suggestions?

Scorpion70

Hi there, I live in Central Southern England in a first floor flat in what is an extension to an older building. The front of the building is over 100 years old with solid walls although
I'm in the extension at the back which has cavity walls and is apparently insulated. Regardless, when I moved into the flat there was quite a bit of mould on the skirtings in the living room (easy to wipe away), on the unvarnished wooden internal doors (which I will treat and varnish soon) and in the built-in bedroom cupboard, which I stripped out, replastered and repainted with anti-mould paint which seems to have done the job. 

Anyway, I have a cheapo hygrometer and the relative humidity is frequently around the 60% mark. In warmer and wetter conditions earlier this summer, it would hit around 65-70%, and the only thing that brings it down to 45-55% at the moment seems to be my central heating. Not sure why this happens, something to do with warmer air storing more moisture? Regardless, the flat could be ventilated better and I had to spent out £900 upgrading all the radiators back in March. 

I've been researching dehumidifers as I think I'm going to need one going into the autumn and winter. 

It seems desiccant models are potentially safer and work better at colder temperatures, but use more power so will cost more in the long run. 
Most places seem to suggest that despite refigerant models potentially being less effective under 18C, desiccant models are not really necessary in heated rooms in the UK and refigerant models will do just fine. 

Ideally I'd like a dehumidifer with built-in airpurification too (HEPA filter not an ioniser) , that has a laundry boost mode too for clothes. 
I found a desiccant model with the above by brand "Electriq" which has laundry mode and HEPA filter but they seem new and more unknown compared to Meaco and Ebac. 

Any suggestions? 

Debran

The three with the highest scores, according to Which? are are Meaco brand.

Meaco DD8L, scoring 81%

Meaco DD8L Zambezi, scoring 81%

Meaco Platinum 20L Low Energy, scoring 80%

greyteam1959

A cheap hygrometer is about useless & the reading should be taken as such.
Sort out the cause of the poor ventilation & you will probably sort out the mould problem.
Take a good look at the insulation in the lift space if you have one.
Dehumidifiers will not solve the problems you have only mask them.
Positive Input Ventilation may cure your ventilation problem look it up.

Scorpion70

greyteam1959 said:

A cheap hygrometer is about useless & the reading should be taken as such.
Sort out the cause of the poor ventilation & you will probably sort out the mould problem.
Take a good look at the insulation in the lift space if you have one.
Dehumidifiers will not solve the problems you have only mask them.
Positive Input Ventilation may cure your ventilation problem look it up.

You're not wrong. It's a hygrometer from Beurer which I bought from Lakeland. 
The ventilation issue....difficult to say. This flat has cavity wall insulation and double glazing. Previous owner said it was much more breathable before double glazing was put in. I have a new extractor fan in the bathroom, I open windows during and after cooking and showers etc. 

As for insulation in loft space, I only had 160mm but upgraded that to 300mm back in spring. 
PIV I am familiar with and I know its more of a long-term solution, and I was going to go down that route, but this is my first place and I don't intend to live here for more than a few years or so, so I think I'm just going to get a dehumifier for now. 

pogofish

I find the wider temperature range and potentially quieter running make the desiccant type more useful for my house.

My first dehumidifier was a refrigerant type - borrowed for a couple of months to see if it would help and it was a bit of a PITA - louder/less efficient and requiring a bit of heat around the place to work most effectively, although more modern models may be better?

The relatively inexpensive Eco-Air brand has proved good/reliable for me. Lasting longer than my previous DeLonghis, although one of the Eco Air model range does look like an alternatively badged version of a DeLonghi model which started developing intermittent  problems at around two years.

I agree about the cheap hygrometers- about all they are good for is telling you that the humidity has gone up or down but any actual figure is quite arbitrary.

Mistral001

I am a fan of humidifiers.  They can be a useful tool to condition the air and not something you just use to fix a problem such as condensation.  I have found that overall they save me money on heating bills as I use one in rotation in rooms I do not use much such as spare bedrooms resulting in not needing to heat them in the winter. 
 
I would not use them instead of ventilation or as a clothes dryer, which seems to be what the OP is suggesting.

meat2veg

Well this needs updating. 
Purchased a Compressing ProBreeze 30ltr/day dehumidifier and put it in the same room as my 14 month old Desiccant ProBreeze dehumidifier.
Set the them for over night extraction

Room temp 21.5 degrees.
Compressor set at 35% (yes far lower ???)
Desiccant set at 45%

In the morning the Compressor (Brand New) had been on all night and extracted nothing. 
The Desiccant had been on and off all night and extracted 1.4ltrs.

In my view even though the Desiccant used more energy it was by far the most efficient at extraction which is the required action of the device. Thus returning more fruitage for a little more power. 

The problem is the companies don't like making them. 
Desiccant is the way to go in the UK.

meat2veg

BTW Cheap Hygrometers are fairly accurate. It's where you position them is the issue. Damp areas exist in a damp home.

Jonboy_1984

Our refrigerant version has a strange dust flap on the top that needs manually opening (our previous one automatically opened it) and does nothing whilst it is closed. We only used to run it late November to March-ish as opening a window slightly was just as efficient the rest of the time.

littleteapot

meat2veg said:

Room temp 21.5 degrees.
Compressor set at 35% (yes far lower ???)
Desiccant set at 45%

In the morning the Compressor (Brand New) had been on all night and extracted nothing. 
The Desiccant had been on and off all night and extracted 1.4ltrs.

For getting very low air RH levels my findings have been the same - dessicant dehumidifiers are much more effective, and I've found this with various models over 20 years in different properties.

The difference in power consumptions can be quite large though. As an example we currently have two dehumidifiers from the same manufacturer (Meaco). One is a compressor, the other dessicant.

The compressor one uses about 250w. The dessicant one uses 300-600w depending on how far above the setpoint the current humidity is. However this is offset to some extent by a reduced need for heating in the rooms it operates.

Where there are poorly insulated walls, the dessicant option is really needed to keep the RH of the air low enough to prevent condensation and mould on the cold surfaces of the walls. Therefore it sounds like that's the best option for your property. In my experience compressor ones struggle to get the RH below 45-50%