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dehumifiers

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jamie128

Original Poster:

1,604 posts

82 months

Saturday 6th October 2012
quotequote all
Does anyone use these to reduce heating costs as a lower humidity means the temperature percieved is a lot higher is this correct?

Simpo Two

66,645 posts

177 months

Saturday 6th October 2012
quotequote all
Never heard of that one. And the dehumidifier will cost money to run, and your houseplants will die...

jamie128

Original Poster:

1,604 posts

82 months

Saturday 6th October 2012
quotequote all
Simpo Two said:
Never heard of that one. And the dehumidifier will cost money to run, and your houseplants will die...
Apparently heating a dryer house is easier and quicker, i dont have houseplants

Simpo Two

66,645 posts

177 months

Saturday 6th October 2012
quotequote all
You could argue that the volume being heated needs (fractionally) less power to heat it, but conversely it will cool down faster, so no net gain. Then add the power used to run the DH... so overall effect I think is you lose money but the dehumidifier salesman gets a sale. And you will need to drink more.

Where did you get this idea?

singlecoil

23,484 posts

158 months

Sunday 7th October 2012
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The big question is, how dry is your house at the moment? Do tea-towels etc take a long time to dry (a) or not (b), does paper feel soft(a) or is it crispy(b)? These are things that will give you some idea as to the desirabiltiy of dehumidifying. If the answers are a then a dehumidifier would be a useful addition. If not, don't bother.
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Deva Link

26,934 posts

157 months

Sunday 7th October 2012
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jamie128 said:
....as a lower humidity means the temperature percieved is a lot higher is this correct?
errrr...it's the other way around. And at "normal" temperatures the difference is negligible.

JM

2,503 posts

118 months

Monday 8th October 2012
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jamie128 said:
Does anyone use these to reduce heating costs as a lower humidity means the temperature percieved is a lot higher is this correct?
Is it not that the dehumidifier generates heat, so the other usual heat source doesn't need to run as much?


AndyClockwise

656 posts

74 months

Tuesday 9th October 2012
quotequote all
Surely the air coming out of a dehumidifier is colder than the temperature of the surrounding area?

The water is collected by passing air over a cold condensing plate and so the air leaves colder than when it enters.

If my house isn't warm then the dehumidifier doesn't work as the plate isn't colder than the surrounding area

LeoSayer

5,197 posts

156 months

Tuesday 9th October 2012
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I find the air much drier after running the central heating for a few weeks.

Taking even more moisture away is the last thing I'd want to do.

squeezebm

2,319 posts

117 months

Tuesday 9th October 2012
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AndyClockwise said:
Surely the air coming out of a dehumidifier is colder than the temperature of the surrounding area?

The water is collected by passing air over a cold condensing plate and so the air leaves colder than when it enters.

If my house isn't warm then the dehumidifier doesn't work as the plate isn't colder than the surrounding area
Does the air not pass over the evaporator/evaporative plate of the
system not the condensing plate?

Deva Link

26,934 posts

157 months

Tuesday 9th October 2012
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squeezebm said:
Does the air not pass over the evaporator/evaporative plate of the
system not the condensing plate?
Yes, but then they usually blow if over the condenser to put a bit of heat back into the air. Hence they're no good as a/c units.

sjj84

1,870 posts

131 months

Tuesday 9th October 2012
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I tried putting our ac unit on dehumidifying mode and it did indeed seem to be blowing out slightly colder air than the surrounding area. Wasn't much in it, but certainly felt a little colder, might just have been due to it being blown though.

squeezebm

2,319 posts

117 months

Tuesday 9th October 2012
quotequote all
Deva Link said:
Yes, but then they usually blow if over the condenser to put a bit of heat back into the air. Hence they're no good as a/c units.
Really,have you any figures on the amount of heat that is added by "a bit of heat by blowing air over a condenser" ?

Thanks

Deva Link

26,934 posts

157 months

Tuesday 9th October 2012
quotequote all
squeezebm said:
Really,have you any figures on the amount of heat that is added by "a bit of heat by blowing air over a condenser" ?

Thanks
Can you tell me the room temperature and humidity and the rating and efficiency of the dehumidifier?

squeezebm

2,319 posts

117 months

Tuesday 9th October 2012
quotequote all
Deva Link said:
Can you tell me the room temperature and humidity and the rating and efficiency of the dehumidifier?
You do not require that information as the question was not about a specific dehumidifier ???? I asked what was the amount of heat added by the condensor when the air was blown over it or are you telling me that this varies per unit?

How is this controlled ?

singlecoil

23,484 posts

158 months

Tuesday 9th October 2012
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When water is returned from vapour to liquid it gives up its latent heat of evaporation, so there is a degree of heat recovery with a dehumidifier, although the energy consumed by the compressor will tend to offset any savings.

The simple answer is, if your house is damp then you need one, and if it isn't, you don't.

TheD

2,876 posts

111 months

Tuesday 9th October 2012
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singlecoil said:
When water is returned from vapour to liquid it gives up its latent heat of evaporation, so there is a degree of heat recovery with a dehumidifier, although the energy consumed by the compressor will tend to offset any savings.

The simple answer is, if your house is damp then you need one, and if it isn't, you don't.
Kablammo.....Nail right on the head smile

Pints

18,117 posts

106 months

Tuesday 9th October 2012
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So what recommendations are there for those of us not on powerfully built director salaries?

JM

2,503 posts

118 months

Thursday 11th October 2012
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squeezebm said:
Deva Link said:
Can you tell me the room temperature and humidity and the rating and efficiency of the dehumidifier?
You do not require that information as the question was not about a specific dehumidifier ???? I asked what was the amount of heat added by the condensor when the air was blown over it or are you telling me that this varies per unit?

How is this controlled ?
To give a specific answer all the information would be required. But to give a 'general' answer to the question I would say a few 100 watts, based on a small domestic dehumidifier.
If the cooling capacity is for arguments sake 1Kw, then the heat output would be about 1.2Kw. But what it actually is will depend on conditions in the room, size of unit, refrigerant gas used etc etc.
There is no control over it unless there is a vent to get rid of the heat or a remote condensing unit/coil, but you wont get that on a cheap domestic unit.

Obviously based on a compressor driven refrigerant type dehumidifer.

gjc10212

267 posts

118 months

Thursday 11th October 2012
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Pints said:
So what recommendations are there for those of us not on powerfully built director salaries?
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