Dehumidifier use

[Rodbr]

I have been given a Dehumidifier/air cooler rated at 900w on Dehumidifier mode.

I have never had the need for one before and so unsure when is the best time to run it. It does have a clock/timer.

My garage is used as a workshop restoring parts of my TR2 and so I am using a Hamilton Classics double skin garage for the 3a. I have a Outdoor Carcoon but find that it is not as user friendly as you might like. Tends to scratch the paint if you have to remove on your own. It has now been back to Carcoon for a replacement top cover due to faulty material. I am unsure about the ability to stop mildew which was a problem last winter.

 

O might even try using it inside the HC garage sort belt and braces if we get the bad winter forecast so a the most on 100 years9 Ok heard it all before. Look out the window seems best.

 

Any advice how best to run it as it does create heat switching off may be worse than not using it at all.

 

[Motorsport Mickey]

The worst increase in dampness or humidity in the garage is when the dew point is breached, obviously over winter that will depend upon the fluctuation between the warmer (hopefully) daytime conditions and the colder overnight and early morning conditions before the garage and the world has warmed again.

So short answer if it were me using the dehumidifier I'd have it on a timer and try it from 5pm through to 10am the next morning and measure how the humidity varies in the garage, (there's probably a meter on the unit) notwithstanding the costs of having a 900watt drain on the finances for those hours.

Not sure why you say you have a mildew problem with the outdoor Carcoon, in a different context I've never experienced it with mine (although different beast, indoor Carcoon). As a tip I do try and wipe all residues of leather feed, or soft cleaning products off trim,seats and hoods with just a clean water rinse before it goes in the Carcoon as it occurred to me it may develop some growth over winter if there is any excess product left on it, maybe that's what you had on yours ?

 

As regards the scratching caused by the top cover, again never had that with mine because it's an interior "Carcoon" and the top is suspended inside the garage and so easy to unzip leaving it up and then drive the car out. With the added weight of a double skin as I think the exterior models are I'd certainly be calling for the wife or a mate before trying to remove.

 

Can't you roll up from the edges into the middle and then lift off in one package ? that's what I did with the interior Carcoon before suspending the top from the garage and I've never noticed any scratching caused by it.

 

Mick Richards

Edited October 31, 2014 by Motorsport Mickey

[Rodbr]

Hi Mick,

It transpired that there was an issue with the "silver" coating which cracked off and left the fabric exposed, pretty sure this caused moisture to enter. Happened twice. First time within a year of purchase and they said at the time it had been replaced. Actually they re-coated it. This time a complete new top with new material as there was a batch that was faulty.

The secret is circulation of air and that means opening the vent which in turn introduces moist air. Still think it is the best way to store the car but if I can suspend the top of the Air chamber from the frame of the HC garage it might go some way to stopping damage to paintwork.

 

To be fair during the gales last year the air chamber was trying to take off and only held by the weight of the car and it was being buffeted around by the wind. Probably would not have happened if I had had a cotton car cover fitted as a barrier. The sides of the carcoon were being moved against the car by the wind so not sure it was the single handed removal that was the issue.

 

The cost of running the dehumidifier is the potential downside as it seems it could cost £50-£60 a month but that is all day every day I think. Maybe get one of those power monitors from Maplin.

[TR5tar]

Hi Rod,

I recently found myself investigating the relative merits of a dehumidifier Vs an indoor Carcoon, and came to the conclusion that the dehumidifier was the best route for me. There's a good discussion of the subject on this thread - http://www.tr-register.co.uk/forums/index.php?/topic/48959-preparing-for-snowmageddon/

It seems that the main thing with a dehumidifier is to make certain that it's a desiccant type, because non-desiccant types stop working below about 5C I'm told. And so, if your garage is likely to fall below 5C in the winter, it might be worth you checking the dehumidifier that you've been given. I'd have to say that at 900W, the dehumidifier you have been given could be quite costly to run. I bought an Ecoair DD122FW Classic MK5 (612W full blast, just over 360W economy mode). It works pretty well in my double garage.

When I bought the dehumidifier I received a digital Relative Humidity (RH) gauge, which you'll need to make sure that the dehumidifier is doing the job. As I understand things, if you can get the RH to 55% or below, then there's little chance of breeching the dew point, regardless of the temperature. I found this useful Dew Point Calculator - http://www.dpcalc.org/

As Mick says, it's the fluctuation between the daytime and night time temperature (times when temperatures are either rising or falling) that can cause the problems, so I run my dehumidifier from about 4pm until about 9 or 10 in the morning, to keep the RH at safe levels. Also, I park the car on a large tarpaulin to stop damp that might rise from the concrete floor.

 

Halford's are stocking large Silica Gel bags at the moment. I don't know if they work or not, but I've stuck one in the car. It can't hurt.

 

Cheers, Darren

Edited October 31, 2014 by TR5tar

[Rodbr]

HMMMMMM!

Seems that it is probably the the refrigerent type and as such probably expensive to run., given that it is an air conditioner as well. Reverse operation? It is a large lump and 900 watt does seem a lot. May try it during the worst of the weather expected. Only works down to 10 degrees C.

[Don H.]

I run a dehumidifier constantly in my basement, and it makes a big difference. I keep the humidistat at 50% and that controls what's normally a too-damp environment just fine. Much of my library is down there and this prevents foxing (mildew) in any of the paper.

 

My garage is uninsulated brick on a concrete slab and we can have all kinds of temperature/humdity excursions here in the US midwest. It's been so cool inside and so humid outside there have been times when opening the door leads to immediate condensation on every surface. I have a full set of tools in the garage so controlling corrosion is a priority.

 

Rather than dehumidify the garage, which would likely tax any dehumidifier, I keep a fan blowing in the garage. Seems to help a lot across the high and low temperature extremes. I've not seen any surface rust on any tools and haven't had any condensation episodes.

[McMuttley]

I was wondering whether to install one of the small circa 4" bathroom extractor fans on a timer, that would pull out any obvious moist air, but also drag some flow through the garage. My only concern was that I would be pulling damp air in and encouraging it to condense ?

[Don H.]

For my detached garage, Austin, I figure the humidity inside isn't much different from outside and keeping the air moving is the best thing I can do. Works well for my situation.

[Alec Pringle]

Those small bathroom fans consume about 15-20w of power, and you need one at each end of the garage - one to pull air in, and one to push it out again. Matching the prevailing wind direction of course !

 

At 40w/hr that's no more than one unit of electricty per day, or not much over a quid per week.

 

There are fans with a built-in humidity 'stat, which switch themselves on only when needed . . . . .

 

Cheers

 

Alec

[Andrew Smith]

Rod,

 

My garage used to get pretty damp with condensation appearing on my tools and paper and cardboard boxes would feel damp.

 

I now use a couple of Digital Humidity Meters so when the Relative Humidity (RH) gets to 60 - 70% I switch on my Car Storage Dehumidifier specifically for home garages - this takes out 2.5 lts of water overnight when the RH reaches 90+%!

 

I also use an Air Chamber for the TR6 which has an internal frame, so no possibility of it scratching the paint which is why I chose it over a Carcoon - the Air Chamber was recommended to me by Stuart and Paul Harvey and has proven to be exceptional in use.

 

This is useful info: Car Storage FQAs

 

Cheers

Andrew

Edited October 31, 2014 by Andrew Smith

[TRnorm]

Interesting topic and one that has got me looking for my anorak - so I'll apologise in advance for the following!

 

Looking at the difference between (average) day and night temperatures in London (http://www.weather2travel.com/climate-guides/united-kingdom/) its clear that the winter months show a lesser variation between Daytime maximum and Night-time minimum, compared with the summer months - and therefore there is a lesser risk of the temperature falling below the Dew point.

 

So, plugging the Day v Night temperature excursions seen for Nov through to Feb into Darren's Dew point Calculator shows that if the de-humidifier was able to control to 65% RH, the Dew point would be avoided. Further more, the actual maximum moisture content appropriate for the maximum Day temperature for these winter months is less than half what it can be for the summer months with their higher temperatures (http://www.engineeringtoolbox.com/maximum-moisture-content-air-d_1403.html).

So, what's the point I'm making? Well it's simply that if a compressor de-humidifier is less efficient at temperature below say 10C then perhaps this is not as important as first appears??

 

Interestingly, plugging in the summer temperatures into the Dew Point Calculator indicates that controlling the RH to about 55% is necessary if the possibility of condensation is to be avoided (again, for the full average temperature excursion indicate for that time of year). This clearly supports recommendations to set a de-humidifier to 55%RH which is also mentioned in Darren's post.

 

And just to pre-empt likely comments - with my hood being fitted hopefully in the next one or two weeks, I shall be getting out more often.

 

Norman