Cost of running a Dehumidifier

savemoney

We do indeed so why not where a breathing apparatus

Cook in a pan then bathe in the left over hot water

energysavingexp wrote: »

dont forget we also breath out a lot of moisture!

brig001

vaio wrote: »

Doesn't sound quite right but i can't quite say why. Following your logic a dehumidifier would be more efficient heater than an electric fire.

All a dehumidifer does is move liquid from a messy pool on the window cill into the dehumidifier water container, I don't see where any extra energy comes from to exceed the 100% efficiency mark

It didn't sound right when I read it elsewhere, but the logic goes:
Water vapour is in the air because you added heat to evaporate it.
When you remove water from the air, you get the heat back.
A dehumidifier is a heat pump, so will be more than 100% efficient at getting this heat back (heat pump efficiency is Coefficient Of Performance, COP). So, if the COP is 4, you only need to put in 1kWh, to get 4kWh of heat back from the water vapour.

I think this only holds if the water is in the air, and not on a window cill.

I don't really understand it myself, but if my heating usage goes down less than my dehumidifier uses, there must be some truth in it.
Brian.

kats53

LOL I'm enjoying this thread!

energysavingexp

savemoney wrote: »

well the best way is obviously not to try and get condensation in the first place which isnt easy in houses with our modern lifestyle and our desire to cut drafts etc

Try using a extractor fan for cooking and bathing, insulate wheer possible. Open windows to ventilate or have air bricks fitted. Dont dry washing on rads all help but is almost impossible to eliminate it every where

brig001 wrote: »

It didn't sound right when I read it elsewhere, but the logic goes:
Water vapour is in the air because you added heat to evaporate it.
When you remove water from the air, you get the heat back.
A dehumidifier is a heat pump, so will be more than 100% efficient at getting this heat back (heat pump efficiency is Coefficient Of Performance, COP). So, if the COP is 4, you only need to put in 1kWh, to get 4kWh of heat back from the water vapour.

I think this only holds if the water is in the air, and not on a window cill.

I don't really understand it myself, but if my heating usage goes down less than my dehumidifier uses, there must be some truth in it.
Brian.

Does this mean if i use my dehumidifier in a sauna i can heat my whole house for free?:j

vaio

Yep, but heat pumps work by moving energy from a source to a sink, if the source is outside (which you don't pay to heat) and the sink is your living room (which you do pay to heat) then so the energy flow is partly electricity and partly energy from outside, add the two together and you end up with more than 100%.

vaio

brig001 wrote: »

It didn't sound right when I read it elsewhere, but the logic goes:
Water vapour is in the air because you added heat to evaporate it.
When you remove water from the air, you get the heat back.
A dehumidifier is a heat pump, so will be more than 100% efficient at getting this heat back (heat pump efficiency is Coefficient Of Performance, COP). So, if the COP is 4, you only need to put in 1kWh, to get 4kWh of heat back from the water vapour.

I think this only holds if the water is in the air, and not on a window cill.

I don't really understand it myself, but if my heating usage goes down less than my dehumidifier uses, there must be some truth in it.
Brian.

Yep, but heat pumps work by moving energy from a source to a sink, if the source is outside (which you don't pay to heat) and the sink is your living room (which you do pay to heat) then so the energy flow is partly electricity and partly energy from outside, add the two together and you end up with more than 100%.

MRSTITTLEMOUSE

brig001 wrote: »

It didn't sound right when I read it elsewhere, but the logic goes:
Water vapour is in the air because you added heat to evaporate it.
When you remove water from the air, you get the heat back.
A dehumidifier is a heat pump, so will be more than 100% efficient at getting this heat back (heat pump efficiency is Coefficient Of Performance, COP). So, if the COP is 4, you only need to put in 1kWh, to get 4kWh of heat back from the water vapour.

I think this only holds if the water is in the air, and not on a window cill.

I don't really understand it myself, but if my heating usage goes down less than my dehumidifier uses, there must be some truth in it.
Brian.

I don't understand it either but I use a dehumidifyer in my kitchen.
Like the OP we live in a large Victorian house and have condensation issues especially in the kitchen which is a large area and has a stone slab floor.Even when the heating runs constantly the kitchen feels cold,however run the dehumidifyer for a few hours and the room feels much more comfortable.
You can actually feel the difference.
The low cost of running a dehumidifyer is well worth the benefits you get.

brig001

Just found this that explains it better than I can: http://www.iwilltry.org/b/heat-your-home-with-a-dehumidifier/
Makes more sense than my post...
Seems I'm not completely mad after all :j

kats53

Thanks Mrs Tittlemouse thats what I was hoping. My kitchen and utility are the coldest places in my house...usually are in these old buildings. Therefore cold = condensation = damp.
What make of dehumidifier do you have?
Jen

ladydriva

hiyas, does every1 just have 1 dehumidifier in their house? we've got 1 on landing, in a 3 bed semi. is this enough? or should we get 1 downstairs as well?
thanks