I am looking to buy a domestic dehumidifier, any recommendations?

Mike

MuddyMike wrote:

I am looking to buy a domestic dehumidifier, any recommendations?

Mike

What do you want it for? Room area, expected operation times (ie all the
time vs occasionally), doesquiet vs noisy matter?

--
Tim Watts

On 16/12/2011 11:04, MuddyMike wrote:
I am looking to buy a domestic dehumidifier, any recommendations?

Mike



Avoid the no-brand ones from Argos, they are cheap nasty Chinese
construction. Mine was very noisy and failed after three months (fan
gave up). I've since got it jerry rigged with an office fan blowing
through it! Still noisy though (pump chugs loudly).

I've also got a Delonghi which was expensive when bought ten years ago
but it is still running today 24 hours per day! A case of you get what
you pay for.

--
David in Normandy.
To e-mail you must include the password FROG on the
subject line, or it will be automatically deleted
by a filter and not reach my inbox.

In article ,
David in Normandy writes:
On 16/12/2011 11:04, MuddyMike wrote:
I am looking to buy a domestic dehumidifier, any recommendations?

Mike



Avoid the no-brand ones from Argos, they are cheap nasty Chinese
construction. Mine was very noisy and failed after three months (fan
gave up). I've since got it jerry rigged with an office fan blowing
through it! Still noisy though (pump chugs loudly).

I've also got a Delonghi which was expensive when bought ten years ago
but it is still running today 24 hours per day! A case of you get what
you pay for.

I bought 3 from Homebase in a sale about 10 years ago, reduced by 75%.
They looked exactly like an EBAC model, but they are not branded.
One had an early component failure on the control board, but I was
fortunately able to fix that easily, and didn't even bother using
the guarantee. Two of them have been moved around often between
different family members (although I've been careful to observe the
instruction to avoid use for 24 hours after moving).
All still work very well. Can use internal tank, or external drain.
Damn heavy though, which combined with bulk, makes carrying tricky.

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

On 16/12/2011 10:04, MuddyMike wrote:
I am looking to buy a domestic dehumidifier, any recommendations?

Having had a cheap one for the laundry for many years (5+) (in our shop)
which still works OK I went for "the best I could afford" for the 2nd
unit at home.
Mitsibushi seemed like the brand to go for. So I bought one with "auto
dehumidify" feature which changes acceptable RH depending on ambient
temp. Select and forget.
So far well worth the money as it's really quiet nicely put together.
http://www.dehumidifiersuk.com/p/113...-capacity.html
or if wrapped MJE16VX-16 is the model. Would buy again without hesitation.


--
http://www.GymRatZ.co.uk - Fitness+Gym Equipment.
http://www.bodysolid-gym-equipment.co.uk
http://www.trade-price-supplements.co.uk
http://www.water-rower.co.uk

On Dec 16, 10:04 am, "MuddyMike" wrote:
I am looking to buy a domestic dehumidifier, any recommendations?

Mike

continuous drain (i.e. a "pipe out" option rather than internal tank
only is nice.
rest is pch costs vs Gtee level vs noise vs brand snobbery

I have 2 in operation here -
1 BnQ Chinese "£100 bargain" that is big, noisily fanned but
(brutally) effective and has a timer, big tank etc
2 Screwfux alleged "special disount voucher" Ebac Amazon which is
simpler, a lot quieter (but still "not sleepable in same room as"),
small tank, carbon & dust filters.

No.2 stays powered during "non sleeping" hours and the compressor
*&fan* cycles in and out as it pleases, the chinky no.1 keeps the
noisy fan going 100% when on and just cycles the compressor as
required.....

and 1 that died
AMCOR (screwfux again) I miss that one.. it got tipped and
died ;(( not as flash as no.1 in controls, but nice solid build, big
tank.

If you have one near enough check Wickes - ISTR they had a "wickes"
one that was clearly an Ebac Amazon for abt the same as the "special
offer" screwfux price... Like the Wickes concrete mixer with stand
that when picked up was a Belle mini mixer with no sign of "Wickes"
anywhere on it.

Jim K

If you heat by electric-only...
- Meaco DD8L dessicant dehumidifier.
- 380W normal mode, 800W laundry mode = HIGH heating output.
- Dessicant dehumidifer uses a heater as part of their operation, this
must be borne in mind.
- Perform well at low temps, which combines with the heater to
maintain temps higher than a compressor unit.
- DD8L once it has reached your desired humidity setting of 50% or 60%
turns off the heater AND fan, then turns back on every 30mins to
sample the air to see if it needs to dehumidify. It does not leave the
30W fan running all the time like earlier dessicant dehumidifiers.
- If a powercut occurs it turns back on if it was left running (very
useful on a boat or left unattended).
- Not much more they can improve - a side-&-top exit would be better
re air velocity.

Note if you heat by gas 1) you may not need the extra heat provided by
a dessicant dehumidifier and 2) you may not want to pay for it either
compared to gas heating where temperatures are not at very low levels.

If you heat by gas...
- Mitsubishi compressor dehumidifier.
- Well built, digital & non-digital versions
- Very large water tank although a permanent drain can be used as with
all of them.
- Draws about 220-320W from memory, much cheaper to run than a
dessicant unit but TINY HEAT OUTPUT.
- Do not heat a room much, do create draughts in a cold room, do not
perform so well at very low temps unlike dessicant units.

With all dehumidifiers there is a blast of air out of them.
This will blow away the boundary layer of air on walls & ceilings and
can create draughts. So they are not ideally suited near people if the
temperatures are relatively low.

With all dehumidifiers if you have a very high number of Air Changes
Per Hour they will run more often to dehumidify the air - this can
mean running almost continuously. Something to factor in to the
purchase price.

An alternative to dehumidifier is a timed extractor (runs every
4-8-12-24hrs for N minutes) and increasing heating. Warmer air will
hold more moisture, extracting air will remove humidity. Again,
something to factor in re comparison. If you run a typical 4-inch
extractor for 10mins it takes 7mins at 650W to put back the heat
extracted, that is not much re cost.

On Dec 16, 6:15*pm, "js.b1" wrote:
If you heat by electric-only...
- Meaco DD8L dessicant dehumidifier.
- 380W normal mode, 800W laundry mode = HIGH heating output.
- Dessicant dehumidifer uses a heater as part of their operation, this
must be borne in mind.
- Perform well at low temps, which combines with the heater to
maintain temps higher than a compressor unit.
- DD8L once it has reached your desired humidity setting of 50% or 60%
turns off the heater AND fan, then turns back on every 30mins to
sample the air to see if it needs to dehumidify. It does not leave the
30W fan running all the time like earlier dessicant dehumidifiers.
- If a powercut occurs it turns back on if it was left running (very
useful on a boat or left unattended).
- Not much more they can improve - a side-&-top exit would be better
re air velocity.

Note if you heat by gas 1) you may not need the extra heat provided by
a dessicant dehumidifier and 2) you may not want to pay for it either
compared to gas heating where temperatures are not at very low levels.

If you heat by gas...
- Mitsubishi compressor dehumidifier.
- Well built, digital & non-digital versions
- Very large water tank although a permanent drain can be used as with
all of them.
- Draws about 220-320W from memory, much cheaper to run than a
dessicant unit but TINY HEAT OUTPUT.
- Do not heat a room much, do create draughts in a cold room, do not
perform so well at very low temps unlike dessicant units.

With all dehumidifiers there is a blast of air out of them.
This will blow away the boundary layer of air on walls & ceilings and
can create draughts. So they are not ideally suited near people if the
temperatures are relatively low.

With all dehumidifiers if you have a very high number of Air Changes
Per Hour they will run more often to dehumidify the air - this can
mean running almost continuously. Something to factor in to the
purchase price.

An alternative to dehumidifier is a timed extractor (runs every
4-8-12-24hrs for N minutes) and increasing heating. Warmer air will
hold more moisture, extracting air will remove humidity. Again,
something to factor in re comparison. If you run a typical 4-inch
extractor for 10mins it takes 7mins at 650W to put back the heat
extracted, that is not much re cost.

That data suggests a heat loss of 0.7 x 650w = 455w for a 4" extractor
fan. I'm interested in how you arrived at that, it must vary according
to external temp and real world fan airflow.

But an extractor fan brings in air with a lot more vapour than a
dehumidifier puts out, thus it must run for more time to achieve the
same result. Also a 4" fan shifts far less air than a typical
dehumidifier's 7" blade, so there's a big disparity in run times for a
given RH reduction.


NT

On Dec 16, 8:39*pm, NT wrote:
That data suggests a heat loss of 0.7 x 650w = 455w for a 4" extractor
fan. I'm interested in how you arrived at that, it must vary according
to external temp and real world fan airflow.

Cost of running a 4" fan 3 times for 10mins a day...
- 0.5hr x 0.020kW x 11p = 0.11p per day (insignificant).

Cost of heating replacement 0oC air to 20oC
- 90m^3/hr for 10min = 15m^3 of heated air at 20oC extracted
- Assume replaced by air at 0oC (drawn through house vents)
- Heater run on minimum setting which is 650Watts
- Air SPH = 716J/Kg K, air density = 1.3kg/m^3, 1 watt = 1J/sec,
Volume = 15m^3.
- 650Watts * N-seconds / 716 / 1.3 = 20oC rise
- N-seconds = 20 * 1.3 * 716 / 650 * 15 = 430secs = 7.2min.
- 7.2min x 3-times a day = 22 min per day
- cost = 0.37hrs x 0.65kW x 11p = 2.65p

So even if you have to extract more than 3x a day for 10mins, it is
not a big cost.


But an extractor fan brings in air with a lot more vapour

True, but at 0oC air drawn in has very little moisture content.
So a crude calculation, but depending on the need for dehumidification
it swung it to an extractor. I use a 2kW fan heater to blast the temp
back up very quickly.

A dehumidifier costs more to run, but does offer a little heat
(compressor) or a lot of heat (dessicant). On balance the extractor
method works well. The air RH in the room is 56-48% and most
dehumidifiers stop at 50% - which is not low enough to stop
condensation on single glazing.

So on balance the extractor was cheap to buy, cheap to run, and the
saving went in a ****-load of insulation both Marmox & Celotex. Just
got to find time to fit it! :-)

Dehumidifiers work best for open plan or one-floor flats, not so good
across multiple floors and they are not silent if you have to "sleep
with them". For their purchase cost, running cost & eventual
replacement cost I think a proper split mount air-con might be better
value for money. About £279-379, heat pump capability, cooling
capability, plus dehumidification capability and at a lower noise than
most dehumidifiers.

On Dec 17, 12:13*am, "js.b1" wrote:
On Dec 16, 8:39*pm, NT wrote:

That data suggests a heat loss of 0.7 x 650w = 455w for a 4" extractor
fan. I'm interested in how you arrived at that, it must vary according
to external temp and real world fan airflow.

Cost of running a 4" fan 3 times for 10mins a day...
- 0.5hr x 0.020kW x 11p = 0.11p per day (insignificant).

Cost of heating replacement 0oC air to 20oC
- 90m^3/hr for 10min = 15m^3 of heated air at 20oC extracted
- Assume replaced by air at 0oC (drawn through house vents)
- Heater run on minimum setting which is 650Watts
- Air SPH = 716J/Kg K, air density = 1.3kg/m^3, 1 watt = 1J/sec,
Volume = 15m^3.
- 650Watts * N-seconds / 716 / 1.3 = 20oC rise
- N-seconds = 20 * 1.3 * 716 / 650 * 15 = 430secs = 7.2min.
- 7.2min x 3-times a day = 22 min per day
- cost = 0.37hrs x 0.65kW x 11p = 2.65p

So even if you have to extract more than 3x a day for 10mins, it is
not a big cost.

2.76p/day for 30 minutes of run time = £10pa = £200 per 20 yr
appliance life. Fan purchase cost £20, fitting cost £100, total £320.

Last time I put a dehumidifier in somewhere was because the extractor
fan was running a lot more than 30mins a day, and failing to do the
job. If one runs for 10 mins after each bathroom use, which isnt an
uncommon scenario, it might run a dozen times a day = 120 mins,
bringing total costs to £800+£20+£100 = £920 per 20 yrs.


But an extractor fan brings in air with a lot more vapour

True, but at 0oC air drawn in has very little moisture content.
So a crude calculation, but depending on the need for dehumidification
it swung it to an extractor. I use a 2kW fan heater to blast the temp
back up very quickly.

A dehumidifier costs more to run, but does offer a little heat

Lets see. 200w for 10% of the time = 20w ave, cost 0.02 x 24 x 12p =
5.7p/day for 8 months a year = £14 pa. Purchase cost £30 used -£150
new, so total 20yr cost = 280 + 30-150 = £310 - £430.

With gas heating, the heat produced is worth about 1/3 the electricity
cost, or £90 apx, and with electric storage heating its worth 50% or
£140, and with plug-in electric heating its worth 100% or £280.

Total costs - heating fuel saving =
£220-340 for gas heating
£170-290 for electric storage heat
£30-150 for plug-in heating


NT



(compressor) or a lot of heat (dessicant). On balance the extractor
method works well. The air RH in the room is 56-48% and most
dehumidifiers stop at 50% - which is not low enough to stop
condensation on single glazing.

So on balance the extractor was cheap to buy, cheap to run, and the
saving went in a ****-load of insulation both Marmox & Celotex. Just
got to find time to fit it! :-)

Dehumidifiers work best for open plan or one-floor flats, not so good
across multiple floors and they are not silent if you have to "sleep
with them". For their purchase cost, running cost & eventual
replacement cost I think a proper split mount air-con might be better
value for money. About £279-379, heat pump capability, cooling
capability, plus dehumidification capability and at a lower noise than
most dehumidifiers.

NT wrote:
On Dec 16, 6:15 pm, "js.b1" wrote:
If you heat by electric-only...
- Meaco DD8L dessicant dehumidifier.
- 380W normal mode, 800W laundry mode = HIGH heating output.
- Dessicant dehumidifer uses a heater as part of their operation,
this must be borne in mind.
- Perform well at low temps, which combines with the heater to
maintain temps higher than a compressor unit.
- DD8L once it has reached your desired humidity setting of 50% or
60% turns off the heater AND fan, then turns back on every 30mins to
sample the air to see if it needs to dehumidify. It does not leave
the 30W fan running all the time like earlier dessicant
dehumidifiers. - If a powercut occurs it turns back on if it was
left running (very useful on a boat or left unattended).
- Not much more they can improve - a side-&-top exit would be better
re air velocity.

Note if you heat by gas 1) you may not need the extra heat provided
by a dessicant dehumidifier and 2) you may not want to pay for it
either compared to gas heating where temperatures are not at very
low levels.

If you heat by gas...
- Mitsubishi compressor dehumidifier.
- Well built, digital & non-digital versions
- Very large water tank although a permanent drain can be used as
with all of them.
- Draws about 220-320W from memory, much cheaper to run than a
dessicant unit but TINY HEAT OUTPUT.
- Do not heat a room much, do create draughts in a cold room, do not
perform so well at very low temps unlike dessicant units.

With all dehumidifiers there is a blast of air out of them.
This will blow away the boundary layer of air on walls & ceilings and
can create draughts. So they are not ideally suited near people if
the temperatures are relatively low.

With all dehumidifiers if you have a very high number of Air Changes
Per Hour they will run more often to dehumidify the air - this can
mean running almost continuously. Something to factor in to the
purchase price.

An alternative to dehumidifier is a timed extractor (runs every
4-8-12-24hrs for N minutes) and increasing heating. Warmer air will
hold more moisture, extracting air will remove humidity. Again,
something to factor in re comparison. If you run a typical 4-inch
extractor for 10mins it takes 7mins at 650W to put back the heat
extracted, that is not much re cost.

That data suggests a heat loss of 0.7 x 650w = 455w for a 4" extractor
fan. I'm interested in how you arrived at that, it must vary according
to external temp and real world fan airflow.

But an extractor fan brings in air with a lot more vapour than a
dehumidifier puts out, thus it must run for more time to achieve the
same result. Also a 4" fan shifts far less air than a typical
dehumidifier's 7" blade, so there's a big disparity in run times for a
given RH reduction.

But an extractor fan can also give advantageous air changes to other rooms
in the house.


--
Adam

NT wrote:
On Dec 17, 12:13 am, "js.b1" wrote:
On Dec 16, 8:39 pm, NT wrote:

That data suggests a heat loss of 0.7 x 650w = 455w for a 4"
extractor fan. I'm interested in how you arrived at that, it must
vary according to external temp and real world fan airflow.

Cost of running a 4" fan 3 times for 10mins a day...
- 0.5hr x 0.020kW x 11p = 0.11p per day (insignificant).

Cost of heating replacement 0oC air to 20oC
- 90m^3/hr for 10min = 15m^3 of heated air at 20oC extracted
- Assume replaced by air at 0oC (drawn through house vents)
- Heater run on minimum setting which is 650Watts
- Air SPH = 716J/Kg K, air density = 1.3kg/m^3, 1 watt = 1J/sec,
Volume = 15m^3.
- 650Watts * N-seconds / 716 / 1.3 = 20oC rise
- N-seconds = 20 * 1.3 * 716 / 650 * 15 = 430secs = 7.2min.
- 7.2min x 3-times a day = 22 min per day
- cost = 0.37hrs x 0.65kW x 11p = 2.65p

So even if you have to extract more than 3x a day for 10mins, it is
not a big cost.

2.76p/day for 30 minutes of run time = £10pa = £200 per 20 yr
appliance life. Fan purchase cost £20, fitting cost £100, total £320.

Last time I put a dehumidifier in somewhere was because the extractor
fan was running a lot more than 30mins a day, and failing to do the
job. If one runs for 10 mins after each bathroom use, which isnt an
uncommon scenario, it might run a dozen times a day = 120 mins,
bringing total costs to £800+£20+£100 = £920 per 20 yrs.

What would the true cost be if you take into account that for 8 months of
the year the reheating costs are zero as the heating is not on?

--
Adam

On Dec 17, 10:48 am, "ARWadsworth"
wrote:

snipped a la grimly

What would the true cost be if you take into account that for 8 months of
the year the reheating costs are zero as the heating is not on?

spoilsport ;p

Jim K

On Dec 17, 10:27*am, NT wrote:
Lets see. 200w for 10% of the time = 20w ave, cost 0.02 x 24 x 12p =
5.7p/day for 8 months a year = £14 pa. Purchase cost £30 used -£150
new, so total 20yr cost = *280 + 30-150 = £310 - £430.

No chance, unless you have a very modern house & too-low ACH.

Running 30% of the time = 0.2kW x 8hrs x 12p x (8/12*365)/100 = £47
pa.
Purchase cost £300 for 4x Mitsubishi EVX over 20yrs = £1200.
Total 20yr cost = £2140.

Dessicant is probably not a whole lot different - they are £130 but
the
running costs are about double, so the saving of £170 on purchases is
clear but I very much doubt they will last 5yrs. I suspect 4yrs.

I would also add 4 Xpelair fans could well be required over 20yrs.
We will ignore the cheapest shed fans for obvious reasons :-)

Perhaps I am pessimistic on appliance life, both may last 8yrs.

Dehumidifiers can end up per-room or per floor, they do not work well
through closed doors. Great for flats though.

Jim K wrote:
On Dec 17, 10:48 am, "ARWadsworth"
wrote:

snipped a la grimly

What would the true cost be if you take into account that for 8
months of the year the reheating costs are zero as the heating is
not on?

spoilsport ;p

Me?

--
Adam

Jim K wrote:
On Dec 17, 10:48 am, "ARWadsworth"
wrote:

snipped a la grimly

What would the true cost be if you take into account that for 8
months of the year the reheating costs are zero as the heating is
not on?

spoilsport ;p

Well it looks like I am not going to get an answer.

Those calculatons looked like they were done by the Greek Finance Minister
and I say that fans are better than dehimidifiers.

--
Adam