Dehumidifier: Compressor or Dessicant?

[michaeld121]

This one's a bit OT, but I'm hoping someone can help:

I'm buying a dehumidifier to help with a condensation problem in my 3 bed house. I've narrowed it down to the Amcor PLDM18 (see

or the Prem-I-Air PRDHZ80U (see The Amcor is based on normal compressor technology, while the Prem-I-Air is based on a newer dessicant technology. According to one of the companies I spoke to the Prem-I- Air is probably going to be more effective for my purposes & has other smaller advantages (eg quieter & lighter).

The company that recommended it did point out the possible downside that it is a higher wattage (ie 620w vs 260w) but reckoned that it could well work out at a similar cost in the long run, as it would be on less. Is that likely?

Thanks,

Michael

[Pete C]

Hi,

I'd get the compressor one, if you want to heat your home it's cheapest do to so with gas ch instead of waste heat from a dehumidifier.

If getting a compressor one try a smaller one first, as on the bigger ones the compressor can be fairly noisy.

cheers, Pete.

[meow2222]

Dessicant wheel dhs use around twice as much energy, and cost more to buy as well. Their application is in situations where temp is below 12C, conditions in which compressor types are ineffective. Compressor is the choice for nearly all living situations.

However I'd steer clear of Amcor, they have significant problems.

As someone else said, stick with the low power ones for domestic use as theyre quiet.

NT

[mail]

(see

or the Prem-I-Air PRDHZ80U (see The Amcor is based on normal compressor

Dear Michael Have you considered the alternative control method avoiding the need for desiccation? namely stopping the water coming in in the first place? It may be that with appropriate trickle vents and life changes you can avoid this purchase. If you cannot then I would go for the compressor (non-desiccant) version but remember they only work if you close all the windows and doors and heat the place - just the opposite of what you want to control condensation! Chris

[Chris Hodges]

True (ish) but if you then have to vent warm air outside because it's moist and then heat fresh air it can go the other way - don't forget that as well as the waste heat (input power) you get the latent heat from condesing the water.

[Chris Hodges]

In practice this means no showers and no drying washing indoors or quite a lot of ventilation.

A dehumidifer is cheaper, smaller and more efficient than a tumble drier, for example, if you assume it's too wet to dry washing outside.

[Chris Hodges]

We've had a "Challenge" (Argos) 200W input power and a built in humidistat for a few years now, still going strong.

[michaeld121]

Chris,

Yes I have looked at the causes & have made the changes that we can (eg installing a decent bathroom fan). However until we have an extension done we're stuck with poor ventilation in the kitchen and the problem of continual drying of clothes from our 2 small children. Both things should change over time...

In terms of buying a dehumidifier - I've gone for a compressor as per the consensus. I'd just bought it when I saw the comment about Amcor, so I'll have to see how I get on.

Thanks for the responses,

Michael

[Pete C]

I agree, what I meant is extra heat over and above the _total_ heat derived from the dehumidifier.

I looked into the cost of dehumidifier vs ventilation and gas ch:

So IMHO once the air humidity is below 65% it's reasonably likely to be cheaper to use a dehumidifier, better control at least.

So a humidistatic kitchen/bathroom fan could be worth having but a dehumidifer could well be cheaper than leaving windows open for too long.

cheers, Pete.

[Andrew Gabriel]

I'd suggest investing in a hygrometer, to make sure you aren't over-drying the air, which can cause problems with timber in the area (furniture or part of the building). You can pick up a cheap greenhouse one for a couple of quid. The built-in humidistats can be very crude.

[mail]

I beg to differ on one or two points and agree on others It means that if you have a shower you open the window for 20 mins or so immediately afterwards It most certainly does mean no drying of washing inside which is a major cause of such problems How about putting the de-humidifier inside a sealed large room/ container and drying the washing in that? bit like a large condensing drier? just a thought It also means putting lids on saucepans, not leaving bathwater or other water standing with washing in it spin drying at high revs leaving a window open at night in the bedroom (1.5L per person per night) and all the other ways of keeping water vapour production limited Chris