How much does it cost to run a dehumidifier?

How much does it cost to run a dehumidifier?

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Discussion

Theoldfm

Original Poster:

398 posts

186 months

Tuesday 27th January 2015
quotequote all
As the title really.

Just bought one from screwfix for my new garage and ideally would like to leave it on 24/7 but would like to know what the likely running costs would be. It's this one by the way:

http://www.screwfix.com/p/16ltr-dehumidifier/49718

Thanks

B17NNS

18,506 posts

246 months

Tuesday 27th January 2015
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Bucket loads.

toohuge

3,429 posts

215 months

Tuesday 27th January 2015
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It depends how you set it up. If you tub it on a constant setting the usage will be pretty high as the compressor will be running all the time. If you set it at 45% got example, once it's reduced the humidity to that level, it kick in and out when you need it.

Check the instruction manual for the consumption and work it out from there.

Our dehumidifier running in the winter, although with electric heat running was cheaper than our summer bill running just the ac.

All that jazz

7,632 posts

145 months

Tuesday 27th January 2015
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Rough yard stick - the use about the same as your kitchen fridge if you use them on the recommended setting (which is about 65-70% on the dial on mine). They use a noticeable amount but not enough for you to be worrying about reaching for the dial. My produces about 3 litres of water per day from down in the foyer of the upstairs flat I'm renting at the moment and needs daily emptying. Put them in an open area, not against or near walls.

singlecoil

33,311 posts

245 months

Wednesday 28th January 2015
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How warm is it in your garage? Dehumidifiers like that don't work very well at low temperatures. Also, how easy is it for new moisture and/or damp air to get in to replace whatever the dehumidifier is removing?

Andehh

7,107 posts

205 months

Wednesday 28th January 2015
quotequote all
http://www.ukpower.co.uk/tools/running_costs_elect...

Really not much in the big scheme of things!

FlipFlopGriff

7,144 posts

246 months

Wednesday 28th January 2015
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At 250w and running 10 hours a day it will use 2.5kW. At about 11p a kW that's 27.5p a day or £100 per year.
I had 2 Ruby Dry desiccant dehumidifiers going 24/7 before we had the heating installed and they cost about £200 each per annum to run. If I was buying another I'd get one of these:
http://www.dehumidifiersuk.com/p/1174053/meaco-dd8...
Works at low temps which I think the one you've bought won't, sort of defeating the object. Ours was still drawing water when the temp was down to 2/3 degrees (in the conservatory) and it also kicked out a little bit of heat which is a bonus.
FFG

Craikeybaby

10,369 posts

224 months

Wednesday 28th January 2015
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Interesting, I need to do something to reduce the humidity in the garage, especailly over winter.

Is it going to be more efficient to run a dehumidifier or heat the garage slightly to keep it warmer than outside?

VxDuncan

2,850 posts

233 months

Wednesday 28th January 2015
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Don't forget though that the energy isn't wasted - most of the waste energy will go toward background heat for the garage. Plus there's the added advantage that the drier air takes less energy to heat so if you are using a heater in the garage regularly the it'll take less energy to bring it upto the same temp.

Johnnytheboy

24,498 posts

185 months

Wednesday 28th January 2015
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I installed one in my father's garage (where my rustbucket lives).

Initially we set it to run on auto and the highest humidity setting; it always seemed to be running on high speed when we went in there. He then got a whopping electricity bill so we set it to manual low and it's made a negligible difference to his bills compared to before I bought it.

singlecoil

33,311 posts

245 months

Wednesday 28th January 2015
quotequote all
The single most important thing about maintaining a dry garage is insulation. It's no good drying and/or warming the air if it then escapes and is replaced by cold wet air and/or moisture through the floor, walls or ceiling. And garage doors are particularly difficult to insulate and seal.

If the OP provides some details of the type of garage he has, we might be able to make some suggestions.

Craikeybaby

10,369 posts

224 months

Wednesday 28th January 2015
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I've got an insulated Hormann sectional door, and a membrane under the concrete floor. The roof will be insulated in the spring.

Theoldfm

Original Poster:

398 posts

186 months

Wednesday 28th January 2015
quotequote all
singlecoil said:
The single most important thing about maintaining a dry garage is insulation. It's no good drying and/or warming the air if it then escapes and is replaced by cold wet air and/or moisture through the floor, walls or ceiling. And garage doors are particularly difficult to insulate and seal.

If the OP provides some details of the type of garage he has, we might be able to make some suggestions.
Ok then.

It is a double garage 7.5 x 6.0m internally with a 2.4m ceiling height. The walls are two 100mm blockwork skins with a 100mm insulated cavity.

The garage has a room over and I have installed 100mm celotex between the joists with 50mm under the joists. I have also installed 170mm mineral wool insulation under the floor on the upper floor.

The garage doors are 45mm insulated sectional up and over doors with rubber seals.

The slab is 100mm concrete on 200mm type 1 stone.... Enough info?

Cheers

DrDoofenshmirtz

15,185 posts

199 months

Wednesday 28th January 2015
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FlipFlopGriff said:
At 250w and running 10 hours a day it will use 2.5kW. At about 11p a kW that's 27.5p a day or £100 per year.
I had 2 Ruby Dry desiccant dehumidifiers going 24/7 before we had the heating installed and they cost about £200 each per annum to run. If I was buying another I'd get one of these:
http://www.dehumidifiersuk.com/p/1174053/meaco-dd8...
Works at low temps which I think the one you've bought won't, sort of defeating the object. Ours was still drawing water when the temp was down to 2/3 degrees (in the conservatory) and it also kicked out a little bit of heat which is a bonus.
FFG
Not the same things though...
Desiccant dehumidifier = up to ~650 watts on full power. Compressor dehumidifier ~230 watts.

Desiccant: Work better at lower temps, produce some useful heat, quiet, prone to heating element/motor drive failure, cost more to run.
Compressor: Would go into 'defrost mode' more in low temps outside, noisy, don't dehumidify as quick, more reliable, use less power.

If you want to use a dehumidifier indoors, I'd go for a Desiccant type purely because they're quieter and kick out some heat. In a garage, go for a compressor type. The problem with using a dehumidifier in a garage is that you're always pulling in humid air from outside (which is why you should keep the windows closed indoors), so it'll be running nearly 24/7...a desiccant type dehumidifier will cost over twice the cost to run.





Sleepers

317 posts

164 months

Thursday 29th January 2015
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Surely you just need to buy an electricity monitor?

E.g.

http://www.maplin.co.uk/p/13a-plug-in-energy-savin...

FlipFlopGriff

7,144 posts

246 months

Thursday 29th January 2015
quotequote all
DrDoofenshmirtz said:
Not the same things though...
Desiccant dehumidifier = up to ~650 watts on full power. Compressor dehumidifier ~230 watts.

Desiccant: Work better at lower temps, produce some useful heat, quiet, prone to heating element/motor drive failure, cost more to run.
Compressor: Would go into 'defrost mode' more in low temps outside, noisy, don't dehumidify as quick, more reliable, use less power.

If you want to use a dehumidifier indoors, I'd go for a Desiccant type purely because they're quieter and kick out some heat. In a garage, go for a compressor type. The problem with using a dehumidifier in a garage is that you're always pulling in humid air from outside (which is why you should keep the windows closed indoors), so it'll be running nearly 24/7...a desiccant type dehumidifier will cost over twice the cost to run.
Agreed, but who heats a garage?
FFG

JD

2,769 posts

227 months

Thursday 29th January 2015
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Hi OP,

Assuming you are after a dehumidifier for the purpose of vehicle preservation, you will want to achieve an RH of around 55-60%.

For your 110m³ garage, the unit in your link would not be sufficient, and also with a minimum operating temperature of 5°C I would expect a lot of time spent deicing.

If you are serious about proper dehumidification feel free to PM me, I work for a UK heat pump manufacturer and am happy to help.