This is true of all air dryers, of all technologies. As air temp drops
the air contains less moisture, so less is extracted.
But since houses stay near to 20C, the change in extraction rate over
temp swings is not particularly relevant.
never known that yet, though admittedly I'm not a prolific purchaser
true of any dehumidifier system.
Simpler than a basic microwave in fact. Why do mfrs introduce new tech
products? Is it because they believe their own marketing blurb? No,
its to make higher profit.
Large industrial sized compressors are expensive, large desiccant
wheels are not.
no, they take more power.
No form of air drying is free, compressor dehumidifiers are the
cheapest option I've found yet. Fans cost less to buy and install, but
chuck a lot of heat out, and are very much less effective than a
proper dehumidifier. A lock that allows a window to be secured ajar is
the cheapest in the short term, but of course wastes heat just like a
The ideal is to solve the source of the dampness, and do it in a no
run cost way. Often this is achievable, but not in all cases. 5
showers a day means a dehumidifier. Or, if you live alone, a sanity
Oh I just wish our cellar/pantry did, even in summer. It is buried into the
side of a wet hill and is permanently cold and damp so we've blocked it off
and left unused for now. But would like to at least keep the damp there
under some sort of control.
Oh continually. Must have several air changes a day though the wall fan we
put in but that's why it's so cold in there :-(
You can see water actually trickling in though the wall on bad days so it's
isn't really damp, more like running water :-) It used to be the local
abattoir so I assume the cold was useful back then. The hooks for hanging
carcases are still in the ceiling with a drain in the middle of the room
indirectly feeding into the water supply to the local village.
Oh I see :( If its that bad I'd be wanting to check the floor joists
above for rot, and I'd get one of the bigger model dehumidifiers that
can extract more per day. Their quoted extraction rates are,
predictably, under somewhat unrealistic optimistic conditions.
IMlimitedE the real world extraction rates arent even vaguely
comparable to the claims.
Sounds like a better approach would be to dig down beside the house
outside and put a barrier in, but that doesnt come cheap, and would
need a struc eng to check on how it could be done. Money tends to rule
Have you spoken with the period property people? I'm wondering if
gravel plus drain might even do you some good - impossible to know
without enough details though. It almost sounds as if your cellar is
below the water table!
Or maybe you could just plug the drain and have an indoor swimming
Did that a while back. They were rotten :-(
Currently the end of the house is an open two storey unused space. Need to
preserve it whilst we get the rest of the house restored, then thinking of
building a two storey self contained metal structure (including stairs, etc)
within this space so that damp can be drained away around the outside.
We tried one of the compressor ones a while back and took it back as it did
nothing. We now understand this was because the lowest working temperature
of these appears to be higher than this area reaches on the hottest summer
day. The ones mentioned earlier in this post claim to work down to 5 deg C
which is more realistic.
And the local council might have something to say about me removing one of
their unnumbered roads
Had a long conversation with some of the real experts on there two years ago
(Chris Turner, GreenMan, etc) and have been working through them since then.
That's what Chris suggested and has been done where HM's highway doesn't get
in the way. Definitely helped but you wouldn't believe how bad it was when
we started. At least it no longer smells damp.
My whole house is below the water table !! We are on the side of a typical
Peak District hill - i.e. saturated. Currently our field has standing water
on it everywhere. The sheep are asking for wellington boots :-)
Metal doesnt like damp at all. Concrete would be much cheaper and
tolerates damp. Why metal?
Compressor models will work down close to freezing point, as long as
they have a defrost on timer function. If they lack that, the cold
element will freeze solid at low working temps, and stop working. I
suspect that may be the problem. Or else possibly it froze up so
quickly that the daily defrost cycle just wasnt adequate - boosting
airflow rate would fix that, with a big fat external fan stuck on the
air intake. Looking at the cooling coil after its been running a bit
will tell you: if its icing, increase the airflow some more.
The extract rate will fall with falling temp for all types,
inevitably, as the air just doesnt hold much moisture at low temps.
BTW lime makes a workable desiccant, so you could test the rotor
technology with a box a fan and a bag of lime, see what sort of
extraction you get.
Fussy buggers arent they?
It might be possible to do it by removing a brick, scraping a space
out on the other side 18" wide, or however much you can, filling space
with gravel, and replacing said brick. And repeating all over the
wall. And while youre doing it, you might be able to paint the other
side of the wall with something tarry - not perfectly, but enough to
make a huge difference.
Inserting concrete in there would also help, on the other side of the
wall, 3:1 crete is pretty much impervious.
Ha. Well, have you installed weep holes? Weep holes would desaturate
the ground on the other side of the wall to some extent. Since you
dont really want the water running in, drill weep hole and epoxy pipe
into it, run pipes to drainage.
Sounds like youve got a very difficult case there.
I'm guessing also youve not replaced the wall mortar? In an old house
the lime will all be thoroughly porous, in a powdery state by now.
Cutting it out and getting 3:1 cement in there would fix that. As
you'll know from the PP folk this would not usually be considered the
right thing to do, but in this case it sounds like just whats needed.
Why 3:1? Waterproof. The downside is the potential for brick cracking
if the house should move/subside, but it sounds like a good risk swap
in this case.
I imagnie a 4" interior concrete block wall would be the way to go,
tied to the existing wall, after thorough approaches to reducing
damp/wet. Using SS ties of course.
One thought does occur: I just wonder if ventilation could possibly be
making things worse, if the cellar is colder than outdoor temp,
venting will result in condensation and make it wetter. Venting only
helps if indoor temp > outdoor.
I really hope this house was very very cheap, cos it sounds a badun.
Plastic coated metal is impervious to damp and gives a seperate structure
just sitting on 6 to 8 struts in the ground Concrete would need major
foundations and have to attach to the existing building everywhere which is
I expert where damp will collect and may damage what is left.
Unfortunately it's a random stone wall 2 feet thick :-)
This is what the previous owner tried at the side of the house. I can't say
it has or hasn't worked as I don't know how bad it was before, but the wall
is still damp. In fact you can see the line where the concrete stops (even
through 2' of stone) as the wall suddenly gets drier.
This sounds interesting. I assume this is into the uphill side of the hill.
Any more details or links ?
Varies. The house had a lime render until 1999 and this kept the mortar in
fairly good shape. I have repointed in lime where needed though and am
currently playing with lime renders to find the optimum one that will stick
in the gales we get here. Unfortunately what you end up needing with is a
sacrificial top layer over a base coat. By the time the top layer fails the
base coat is absolutely solid. Must be an easier way though.
It's a random stone house and moves regularly :-) There are some concrete
repairs and these have sometimes called stone cracking so I'm trying to get
rid of it slowly.
That's a good point. Which seems to suggest I should only vent at night.
That doesn't sound right but could be.
Nope. But most of house is coming on fine. It has various bits from 1700s
to 1980s and is huge. The part we are discussing here is the oldest part
right down one end and even if I just sealed it off for good we probably
wouldn't miss it.
Once complete the gain in value round here will have made it well worth
Of course it would have been far easier/cheaper to demolish and start again
but Peak Park Authority won't allow that.
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