I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room. So I've read
http://www.wiki.diyfaq.org.uk/index.php?title=Clothes_Dryer
and the page it links to about dehumidifiers, and the thread
on dehumidifier selection that that links to.

I'm reckoning on a 200W-ish dehumidifier (Ebac 2650e, say,
which is 207 Watts on full), but in the thread mentioned
above, this post
http://groups.google.co.uk/group/uk.d-i-y/msg/f101fc341cb4351a
does some maths comparing dehumidifiers with ventilation --
it's not clear cut when you get your heat from gas (as I do)
and heat recovery ventilation would push in the direction of
ventilation, so an alternative would be to use a Vent-axia
HR25H http://www.vent-axia.com/products/vacas/hr25.asp.
The HR25 consumes only 25W on boost (I don't know how much
of that heat goes outside and how much comes in; if I'd been
designing the thing I'd cool the motor with the incoming air
after the heat exchanger, but I don't know if they did
that). The room would be kept up to temperature by a TRV
controlled radiator.

Now, I don't know how to do the calculations. How much water
can 55m³/hr of warmed-up outside air shift? What happens to
the RH when you warm air up? And so on. I don't suppose it's
hard to find out, but it would take quite a while to get it
all down pat, so I'm hoping someone here already knows how
to compare the energy costs of the two options. The data on
the vent axia site seems fairly complete, but I can't see
from Ebac's how much air their unit shifts.

This is in Cambridge, so the outside RH in winter (I'll dry
outdoors the rest of the year) averages around 80% with the
temperature averaging in the region of 5-10°C.

can anyone help?

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2008-04-26)

Jon Fairbairn used his keyboard to write :
can anyone help?

Consider not only a dehumidifier, but a cheap fan to stir the air
around the room. It is not only dry air which dries clothes, but air
flow passing the clothes. A good out door drying day needs low humidity
and a good breeze, the temperature is secondary.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article ,
Jon Fairbairn writes:

I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room. So I've read
http://www.wiki.diyfaq.org.uk/index.php?title=Clothes_Dryer

I just read that, and it's filled up with lots of waffle
and bull**** since I last looked. Go back to an older version...

http://www.wiki.diyfaq.org.uk/index....yer&oldid=2179

and the page it links to about dehumidifiers, and the thread
on dehumidifier selection that that links to.

I'm reckoning on a 200W-ish dehumidifier (Ebac 2650e, say,
which is 207 Watts on full), but in the thread mentioned
above, this post
http://groups.google.co.uk/group/uk.d-i-y/msg/f101fc341cb4351a
does some maths comparing dehumidifiers with ventilation --
it's not clear cut when you get your heat from gas (as I do)
and heat recovery ventilation would push in the direction of
ventilation, so an alternative would be to use a Vent-axia
HR25H http://www.vent-axia.com/products/vacas/hr25.asp.
The HR25 consumes only 25W on boost (I don't know how much
of that heat goes outside and how much comes in; if I'd been
designing the thing I'd cool the motor with the incoming air
after the heat exchanger, but I don't know if they did
that). The room would be kept up to temperature by a TRV
controlled radiator.

It works best at higher temperatures than TRV's normally go to.
I run it at 30C, being the limit of what my dehumidifier can
handle, but if you are using a radiator, I would run it at full
output during drying for most effectiveness (biggest difference
in humidity of the outdoor and indoor temperatures). This will
require higher radiator output than you might otherwise expect
in such a room.

Now, I don't know how to do the calculations. How much water
can 55m³/hr of warmed-up outside air shift? What happens to
the RH when you warm air up? And so on. I don't suppose it's

It's going to be very difficult to work out. You can easily
calculate the amount of water it might absorb by checking
humidity tables, but you can't know how effectively the
damp material is going to pass moisture into the air, so
you don't know what humidity you are going to reach in the
cupboard. Indeed, this will vary with the amount of exposed
damp material, amount of air circulation (forced circulation
helps a lot), the temperature the radiator manages to get
the air up to, and how damp the material is (which will
change throughout the process).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Jon Fairbairn wrote:

I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room. So I've read
http://www.wiki.diyfaq.org.uk/index.php?title=Clothes_Dryer
and the page it links to about dehumidifiers, and the thread
on dehumidifier selection that that links to.

I'm reckoning on a 200W-ish dehumidifier (Ebac 2650e, say,
which is 207 Watts on full), but in the thread mentioned
above, this post
http://groups.google.co.uk/group/uk.d-i-y/msg/f101fc341cb4351a
does some maths comparing dehumidifiers with ventilation --
it's not clear cut when you get your heat from gas (as I do)
and heat recovery ventilation would push in the direction of
ventilation, so an alternative would be to use a Vent-axia
HR25H http://www.vent-axia.com/products/vacas/hr25.asp.
The HR25 consumes only 25W on boost (I don't know how much
of that heat goes outside and how much comes in; if I'd been
designing the thing I'd cool the motor with the incoming air
after the heat exchanger, but I don't know if they did
that). The room would be kept up to temperature by a TRV
controlled radiator.

Now, I don't know how to do the calculations. How much water
can 55m³/hr of warmed-up outside air shift? What happens to
the RH when you warm air up? And so on. I don't suppose it's
hard to find out, but it would take quite a while to get it
all down pat, so I'm hoping someone here already knows how
to compare the energy costs of the two options. The data on
the vent axia site seems fairly complete, but I can't see
from Ebac's how much air their unit shifts.

This is in Cambridge, so the outside RH in winter (I'll dry
outdoors the rest of the year) averages around 80% with the
temperature averaging in the region of 5-10°C.

can anyone help?


A dehumidifier running 10% of the time eats 20.7w, and your fan eats
25w, and would need to run all the time. The fan chucks heat out -
less when you use recovery, but its still throwing heat out. So the dh
wins on energy use.

But the bigger issue is that the fan wont dry the air anywhere near as
much, so drying will take far longer.

If you install a ceiling fan, overnight drying can be cut down to an
hour or less.

Finally, the link andrew gave is the one with the questionable info in
it. I've asked him to back up what he says, but its yet to happen.
There's simply no reason why dehumidifiers should be the one domestic
appliance that requires mutliple layers of fault protection, unlike
any other appliance. If he can back up what he claims I'd welcome it,
but its hard to see how.


NT

writes:

Jon Fairbairn wrote:

I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room.

A dehumidifier running 10% of the time eats 20.7w, and your fan eats
25w, and would need to run all the time.

Would it? The HR25H has a humidistat, and if your 10% duty
cycle for the dehumidifier is based on humidistat control
(where does the number come from, BTW?), I'd say it was
fairer to assume that the HR25 would be on full the same
proportion of the time and drop to the low setting (1.9W)
the rest of the time. So (1*25+9*1.9)/10 = 4.2 watts on
average.

high = 55m³/h, low = 20m³/h, so a complete air change on
full would take about 17mins, so a 10% duty cycle would mean
a cycle took three hours, so I'd have to expect some
multiple of that for the clothes to dry...

The fan chucks heat out - less when you use recovery, but
its still throwing heat out. So the dh wins on energy use.

but is that win big enough to compensate for the relative
efficiency of electric v gas heat? I'm not yet
convinced. The HR25H description says something about
retaining 84% of the temperature difference, so 0°C outside
and 20° inside (not all that common round here) would mean
the air came in at 17°C (modulo weasel words). Heating a
roomful of dry air back up to 20 would take 60kJ (or one kW
minute). Did I get that right? How much more heat does the
air being damp take?

But the bigger issue is that the fan wont dry the air
anywhere near as much, so drying will take far longer.

I'm not sure I mind that. Currently I often dry indoors on
clothes racks, and while it takes too long, it's not
desperately too long (but it does make the windows steam up).

If you install a ceiling fan, overnight drying can be cut down to an
hour or less.

Even if the room temperature were up at 32°C and the fan
kept the RH up at 90%, it would take an Ebac 2650 1.5 hours
to shift 2l of water, so less than an hour would surprise
me. [I haven't been able to weigh a load of washing
accurately enough to say how much water there is in one at
the end, but it's something like that; cockeyed.com reckons
on 4l for a US machine, but they're typically bigger and
less good at spinning]. Another thing I don't know is what
the performance of dehumidifiers does at lower temperatures.
To heat the room all the way up to 32°C would mean losing a
fair amount of energy through the walls and ceiling (even if
I insulate them properly, which hasn't happened yet: tuit
deficit plus some awkward bits of ceiling and a reluctance
to lose space in an already small house. Horizontal part of
ceiling is OK, though!)

But I'm not sure a ceiling fan's worth it. Ceiling fans
don't seem to be cheap, and waiting overnight doesn't bother
me.

Finally, the link andrew gave is the one with the
questionable info in it. I've asked him to back up what he
says, but its yet to happen. There's simply no reason why
dehumidifiers should be the one domestic appliance that
requires mutliple layers of fault protection, unlike any
other appliance.

Well, if I were intending to install the dh in a small
cupboard I'd be a bit concerned to keep the running
temperature within safe limits, but as I'm talking about a
room, if the dh needs extra protection for running in a
room, it shouldn't be on sale!

--
Jón Fairbairn

On Fri, 23 Jan 2009 19:25:06 +0000, Jon Fairbairn wrote:

it's not clear cut when you get your heat from gas (as I do) and heat
recovery ventilation would push in the direction of ventilation,

I'd go for the KISS heat recovery system. At least all the moisture then
gets dumped outside rather than a tank that you forget to empty. The fan
with humidistat is also fit and forget apart filter cleaning. There may be
problems with conducted noise from a dehumidfier sat on the floor.
Dehumidifiers are much more complex things as well, more to go wrong.

--
Cheers
Dave.

In article ,
Jon Fairbairn writes:
writes:

Jon Fairbairn wrote:

I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room.

A dehumidifier running 10% of the time eats 20.7w, and your fan eats
25w, and would need to run all the time.

Would it? The HR25H has a humidistat, and if your 10% duty
cycle for the dehumidifier is based on humidistat control
(where does the number come from, BTW?), I'd say it was

In my drying cupboard, I have a 400W dehumidifier. I set
the humidistat about half way (never calibrated to see what
that actually corresponds to), and with a full load of washing
hanging in the cupboard, it will run continuously for the
best part of an hour. Then it starts cycling on and off as
there's not enough moisture left in the materials to keep
the humidity high enough, and most things at that stage are
dry except where they are in contact with the hanging rail
or folded over and hence not fully exposed to the air flow
on all sides. (Towels and heavy denims take longer.)

If I forget about it, a couple of hours later it seems to be
permanently off by the humidistat.

Even if the room temperature were up at 32°C and the fan
kept the RH up at 90%, it would take an Ebac 2650 1.5 hours
to shift 2l of water, so less than an hour would surprise
me. [I haven't been able to weigh a load of washing
accurately enough to say how much water there is in one at
the end, but it's something like that; cockeyed.com reckons
on 4l for a US machine, but they're typically bigger and
less good at spinning]. Another thing I don't know is what

I haven't accurately measured it, but I'm guess I get around
a litre out of my dehumidifier for a load of washing with no
towels or denims. That's after a 1400 RPM spin at the end of
the wash cycle. It's noticably more with towels/denims, perhaps
1.5 litres.

the performance of dehumidifiers does at lower temperatures.
To heat the room all the way up to 32°C would mean losing a
fair amount of energy through the walls and ceiling (even if
I insulate them properly, which hasn't happened yet: tuit
deficit plus some awkward bits of ceiling and a reluctance
to lose space in an already small house. Horizontal part of
ceiling is OK, though!)

My drying cupboard goes up to 30C max. If the combination of
the dehumidifier heat and heat from the centralheating pump
and pipework in there takes it above that, I automatically
cut off the dehumidifier to protect it against overheating
itself. The dehumidifier gets it close to 30C by itself, but
it actually requires the heating on to take it over, and it
rarely is when I'm drying stuff in the cupboard.

But I'm not sure a ceiling fan's worth it. Ceiling fans
don't seem to be cheap, and waiting overnight doesn't bother
me.

I'm sure forced air circulation helps, but I just rely on
the fan in the dehumidifier, which is quite powerful.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Jon Fairbairn wrote:
writes:

Jon Fairbairn wrote:

I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room.

A dehumidifier running 10% of the time eats 20.7w, and your fan eats
25w, and would need to run all the time.

Would it? The HR25H has a humidistat, and if your 10% duty
cycle for the dehumidifier is based on humidistat control
(where does the number come from, BTW?), I'd say it was
fairer to assume that the HR25 would be on full the same
proportion of the time

No, because the fan is way less effective at drying the air. IME a fan
can run continuously and not produce as much drying as a dh running
10% of the time.


and drop to the low setting (1.9W)
the rest of the time. So (1*25+9*1.9)/10 = 4.2 watts on
average.

high = 55m³/h, low = 20m³/h, so a complete air change on
full would take about 17mins, so a 10% duty cycle would mean
a cycle took three hours, so I'd have to expect some
multiple of that for the clothes to dry...

The fan chucks heat out - less when you use recovery, but
its still throwing heat out. So the dh wins on energy use.

but is that win big enough to compensate for the relative
efficiency of electric v gas heat? I'm not yet
convinced.

I dont see how that makes sense. The win is a cost win, full stop. Gas
vs elec only changes its value.


The HR25H description says something about
retaining 84% of the temperature difference, so 0°C outside
and 20° inside (not all that common round here) would mean
the air came in at 17°C (modulo weasel words). Heating a
roomful of dry air back up to 20 would take 60kJ (or one kW
minute). Did I get that right? How much more heat does the
air being damp take?

But the bigger issue is that the fan wont dry the air
anywhere near as much, so drying will take far longer.

I'm not sure I mind that.

Sure - but the energy calculations do. Your fan eats the same average
power for 10x as long.

Currently I often dry indoors on
clothes racks, and while it takes too long, it's not
desperately too long (but it does make the windows steam up).

If you install a ceiling fan, overnight drying can be cut down to an
hour or less.

Even if the room temperature were up at 32°C and the fan
kept the RH up at 90%, it would take an Ebac 2650 1.5 hours
to shift 2l of water, so less than an hour would surprise
me.

I dont get that much water out per wash. Perhaps some of it evaporates
into the surrounding rooms.

[I haven't been able to weigh a load of washing
accurately enough to say how much water there is in one at
the end, but it's something like that; cockeyed.com reckons
on 4l for a US machine, but they're typically bigger and
less good at spinning]. Another thing I don't know is what
the performance of dehumidifiers does at lower temperatures.

falls fairly quickly. In practice you wont get near the mfr quoted
extraction rate, since odds are its specced at 30C and youre operating
at 20.

To heat the room all the way up to 32°C would mean losing a
fair amount of energy through the walls and ceiling (even if
I insulate them properly, which hasn't happened yet: tuit
deficit plus some awkward bits of ceiling and a reluctance
to lose space in an already small house. Horizontal part of
ceiling is OK, though!)

theres no need


But I'm not sure a ceiling fan's worth it. Ceiling fans
don't seem to be cheap, and waiting overnight doesn't bother
me.

£17 at Argos last time I looked


Finally, the link andrew gave is the one with the
questionable info in it. I've asked him to back up what he
says, but its yet to happen. There's simply no reason why
dehumidifiers should be the one domestic appliance that
requires mutliple layers of fault protection, unlike any
other appliance.

Well, if I were intending to install the dh in a small
cupboard I'd be a bit concerned to keep the running
temperature within safe limits, but as I'm talking about a
room, if the dh needs extra protection for running in a
room, it shouldn't be on sale!

Even in a cupboard 200w wont get you into trouble. if you go upto a
400-500w machine, thats another story.

Another difference is that dhs are consistently very quiet, whereas
fans vary, and often arent.

Fan purchase cost looks lower, but you have to knock a hole in the
wall to install it and run wiring...


NT

writes:

Jon Fairbairn wrote:
writes:

Jon Fairbairn wrote:
I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room.

A dehumidifier running 10% of the time eats 20.7w, and your fan eats
25w, and would need to run all the time.

Would it? The HR25H has a humidistat, and if your 10% duty
cycle for the dehumidifier is based on humidistat control
(where does the number come from, BTW?), I'd say it was
fairer to assume that the HR25 would be on full the same
proportion of the time

No, because the fan is way less effective at drying the air. IME a fan
can run continuously and not produce as much drying as a dh running
10% of the time.

If you are talking about a plain extractor fan, you have to
ask where the air that replaces what's blown out is coming
from, how it gets heated up and how damp it is by the time
it gets to the drying space. I was hoping to do some
calculations for this, but I still haven't got my head
around calculations with humid air.

and drop to the low setting (1.9W)
the rest of the time. So (1*25+9*1.9)/10 = 4.2 watts on
average.

high = 55m³/h, low = 20m³/h, so a complete air change on
full would take about 17mins, so a 10% duty cycle would mean
a cycle took three hours, so I'd have to expect some
multiple of that for the clothes to dry...

The fan chucks heat out - less when you use recovery, but
its still throwing heat out. So the dh wins on energy use.

but is that win big enough to compensate for the relative
efficiency of electric v gas heat? I'm not yet
convinced.

I dont see how that makes sense. The win is a cost win, full stop. Gas
vs elec only changes its value.

No, because both systems throw heat out. In the case where
the heat is coming from electricity, it's thrown out before
it gets to you. Here's some rough numbers.

Typical combined cycle gas power station efficiency = 60%
average uk electricity transmission loss = 7%

so net result = 56% efficiency ie 44% of energy in gas
(burnt at power station) is lost outside your house

burn gas in boiler = SEDBUK rating of my boiler = 88.6% so lose
12% there, so can lose up to 32% of heat to outside before
losing as much as getting the energy from electricity.

The HR25H description says something about
retaining 84% of the temperature difference, so 0°C outside
and 20° inside (not all that common round here) would mean
the air came in at 17°C (modulo weasel words). Heating a
roomful of dry air back up to 20 would take 60kJ (or one kW
minute). Did I get that right? How much more heat does the
air being damp take?

But the bigger issue is that the fan wont dry the air
anywhere near as much, so drying will take far longer.

I'm not sure I mind that.

Sure - but the energy calculations do. Your fan eats the same average
power for 10x as long.

I remain unconvinced of that. I'd like to see some
calculations; since the air coming in is heated up, it's RH
goes down, but I haven't worked out by how much yet, and I
don't know by how much a dh can reduce it in one pass.

If you install a ceiling fan, overnight drying can be
cut down to an hour or less.

That would apply whichever method were used to get rid of
the water.

Even if the room temperature were up at 32°C and the fan
kept the RH up at 90%, it would take an Ebac 2650 1.5 hours
to shift 2l of water, so less than an hour would surprise
me.

I dont get that much water out per wash. Perhaps some of
it evaporates into the surrounding rooms.

My first experiment with a 2650e produced very close to 1l
of water after about eight hours (no towels). Second go was
more like 1.5l for a load including towels. I don't know
what the duty cycle of the dehumidifier was; the fan was
running constantly (because I told it to). I'll have to see
if I can borrow an energy meter to find out how much is used
in a run like that.

Another thing I don't know is what the performance of
dehumidifiers does at lower temperatures.

falls fairly quickly. In practice you wont get near the mfr quoted
extraction rate, since odds are its specced at 30C and youre operating
at 20.

But by how much?

But I'm not sure a ceiling fan's worth it. Ceiling fans
don't seem to be cheap, and waiting overnight doesn't bother
me.

£17 at Argos last time I looked

Thanks for that. I'd been looking at TLC and they were all
rather a lot more than that. Unfortunately I'd have to
reposition the ceiling rose to fit one :-(

Another difference is that dhs are consistently very quiet, whereas
fans vary, and often arent.

The HR25H that a friend has is very quiet. Quieter than the
2650e dehumidifier (both when comparing full to full and
when comparing low to low).

Fan purchase cost looks lower, but you have to knock a hole in the
wall to install it and run wiring...

No. The HR25H is ludicrously expensive! Maybe they'll come
down if more people use them. Where you have to have an
extractor, they're a definite win.

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2009-01-31)

Jon Fairbairn wrote:
writes:

Jon Fairbairn wrote:
writes:

Jon Fairbairn wrote:

I'm thinking of converting a small room in my house (it's
roughly a 2.5m cube) to use as a clothes drying room/storage
room.

A dehumidifier running 10% of the time eats 20.7w, and your fan eats
25w, and would need to run all the time.

Would it? The HR25H has a humidistat, and if your 10% duty
cycle for the dehumidifier is based on humidistat control
(where does the number come from, BTW?), I'd say it was
fairer to assume that the HR25 would be on full the same
proportion of the time

No, because the fan is way less effective at drying the air. IME a fan
can run continuously and not produce as much drying as a dh running
10% of the time.

If you are talking about a plain extractor fan, you have to
ask where the air that replaces what's blown out is coming
from, how it gets heated up and how damp it is by the time
it gets to the drying space.

from outdoors, by the central heating, and it has the same water
content as outdoor air, but since water vapour capacity increases with
temperature this is a lower RH figure than outdoor air.

I was hoping to do some
calculations for this, but I still haven't got my head
around calculations with humid air.

and drop to the low setting (1.9W)
the rest of the time. So (1*25+9*1.9)/10 = 4.2 watts on
average.

high = 55m³/h, low = 20m³/h, so a complete air change on
full would take about 17mins, so a 10% duty cycle would mean
a cycle took three hours, so I'd have to expect some
multiple of that for the clothes to dry...

The fan chucks heat out - less when you use recovery, but
its still throwing heat out. So the dh wins on energy use.

but is that win big enough to compensate for the relative
efficiency of electric v gas heat? I'm not yet
convinced.

I dont see how that makes sense. The win is a cost win, full stop. Gas
vs elec only changes its value.

No, because both systems throw heat out. In the case where
the heat is coming from electricity, it's thrown out before
it gets to you. Here's some rough numbers.

Typical combined cycle gas power station efficiency = 60%
average uk electricity transmission loss = 7%

so net result = 56% efficiency ie 44% of energy in gas
(burnt at power station) is lost outside your house

burn gas in boiler = SEDBUK rating of my boiler = 88.6% so lose
12% there, so can lose up to 32% of heat to outside before
losing as much as getting the energy from electricity.

OK I see what you're saying, I was just considering what happens in
the house. However if you want to take all that into account its more
complex. There are energy losses at every point in the chain:
drilling & operating the well, national distribution, power plants,
etc, all these and more take energy to implement and maintain.


The HR25H description says something about
retaining 84% of the temperature difference, so 0°C outside
and 20° inside (not all that common round here) would mean
the air came in at 17°C (modulo weasel words). Heating a
roomful of dry air back up to 20 would take 60kJ (or one kW
minute). Did I get that right? How much more heat does the
air being damp take?

But the bigger issue is that the fan wont dry the air
anywhere near as much, so drying will take far longer.

I'm not sure I mind that.

Sure - but the energy calculations do. Your fan eats the same average
power for 10x as long.

I remain unconvinced of that. I'd like to see some
calculations; since the air coming in is heated up, it's RH
goes down, but I haven't worked out by how much yet, and I
don't know by how much a dh can reduce it in one pass.

A portable dh can create a static nuisance if left running too long
when outdoors is pouring with rain all day long, so the 2 do produce
quite different conditions..

If you install a ceiling fan, overnight drying can be
cut down to an hour or less.

That would apply whichever method were used to get rid of
the water.

no, because the RH is quite different.


Even if the room temperature were up at 32°C and the fan
kept the RH up at 90%, it would take an Ebac 2650 1.5 hours
to shift 2l of water, so less than an hour would surprise
me.

I dont get that much water out per wash. Perhaps some of
it evaporates into the surrounding rooms.

My first experiment with a 2650e produced very close to 1l
of water after about eight hours (no towels). Second go was
more like 1.5l for a load including towels. I don't know
what the duty cycle of the dehumidifier was; the fan was
running constantly (because I told it to). I'll have to see
if I can borrow an energy meter to find out how much is used
in a run like that.

Another thing I don't know is what the performance of
dehumidifiers does at lower temperatures.

falls fairly quickly. In practice you wont get near the mfr quoted
extraction rate, since odds are its specced at 30C and youre operating
at 20.

But by how much?

I dont remember...

But I'm not sure a ceiling fan's worth it. Ceiling fans
don't seem to be cheap, and waiting overnight doesn't bother
me.

£17 at Argos last time I looked

Thanks for that. I'd been looking at TLC and they were all
rather a lot more than that. Unfortunately I'd have to
reposition the ceiling rose to fit one :-(

Thats not usually too hard, as long as youre not moving it far.


Another difference is that dhs are consistently very quiet, whereas
fans vary, and often arent.

The HR25H that a friend has is very quiet. Quieter than the
2650e dehumidifier (both when comparing full to full and
when comparing low to low).

models of both vary, the difference is that with fans they often stray
into unacceptable.


Fan purchase cost looks lower, but you have to knock a hole in the
wall to install it and run wiring...

No. The HR25H is ludicrously expensive! Maybe they'll come
down if more people use them. Where you have to have an
extractor, they're a definite win.

is this a 4" fan or a bigun? The large ones do seem excessively
priced, and the 2 manufactureres I asked couldnt give a sensible
answer as to why. Just a small market I guess.


NT