Using a dehumidifier in a garage.
Discussion
I found that the lowest RH I can get is 59% so far, when using Turbo Mode.
The weather is very wet outside because of rain.
I have seen people saying they can maintain the RH in the range of 45%-55% for their cars and tools, so I tried to follow.
However, I did not realise I cannot do the same/similar to my garage.
I would wait for the weather getting warm a bit and see how it affects the RH inside.
In the meantime, I keep turning on the turbo mode (670W), because I don't see too much I can save by using 420W (economy mode).
If the weather get warmer, and the RH does not drop/close to 50%, I would get an extractor fan with timer control.
https://www.tlc-direct.co.uk/Images/Products/size_...
The weather is very wet outside because of rain.
I have seen people saying they can maintain the RH in the range of 45%-55% for their cars and tools, so I tried to follow.
However, I did not realise I cannot do the same/similar to my garage.
I would wait for the weather getting warm a bit and see how it affects the RH inside.
In the meantime, I keep turning on the turbo mode (670W), because I don't see too much I can save by using 420W (economy mode).
If the weather get warmer, and the RH does not drop/close to 50%, I would get an extractor fan with timer control.
https://www.tlc-direct.co.uk/Images/Products/size_...
I have a meaco 8l rotary dessicant in my garage and sealed most of the gaps etc so it works more efficiently. The %rh stays exactly between 50-60% as it's on the middle of 3 settings. Constant drain to outside so no hassle. The drive motor went after 4 years and cost 24 quid from meaco and took an hour to fit myself. So much more convenient than the carcoon I had in my other garage.
Much depends on how often and at what times of the day you bring the car in and out of the garage. I've two compressor units in the four-car garage, plus two of the cars are in Air Chambers. No heating. Sure, compressors are less efficient at low temperatures, but the problem with humidity is the difference in temperature between the air and the metal, not so much the absolute temperature. What you need to do is aim to always have the surfaces at a temperature at at least the dew point of the bulk air surrounding them. This is why ventilation is important.
As others have said, key is insulation. Kingspan or similar is the answer. No need for loads, total abut 50mm is enough, best is 2 thinner sheets so you can overlap as it can be a pain to cut straight and avoid draughts and gaps.
I have 2 double garages each with a DD882 dehumidifier and have had good results, after much testing I find Medium and 60% are the best settings. The fan runs all the time. They are dessicant, importantly if there is a powercut they auto restart, many dehumidifiers don't. Don't notice them using too much power. They have been running for at least 3 years so although they are cheap they seem durable.
Mild steel sheet can be left indefinitely and just doesn't rust, very different to a garage I have which is not dehumidified, wouldn't be without them now. Also the little bit of heat they give off and lack of damp makes for a more pleasant environment for working. Wouldn't want to be without them in the UK climate.
I have a hose that goes through the wall to a small water container that then overflows to a drain. That container has a tap on and is a free supply of distilled water for irons etc. It's pretty much always full this time of year but we sometimes run out in the summer.
Be interested to know how others record temperature and humidity over time ? I have a weatherstation "outdoor" unit in each garage which allows me to set an alarm and that works well but nothing that records historic temp and humidity.
I have 2 double garages each with a DD882 dehumidifier and have had good results, after much testing I find Medium and 60% are the best settings. The fan runs all the time. They are dessicant, importantly if there is a powercut they auto restart, many dehumidifiers don't. Don't notice them using too much power. They have been running for at least 3 years so although they are cheap they seem durable.
Mild steel sheet can be left indefinitely and just doesn't rust, very different to a garage I have which is not dehumidified, wouldn't be without them now. Also the little bit of heat they give off and lack of damp makes for a more pleasant environment for working. Wouldn't want to be without them in the UK climate.
I have a hose that goes through the wall to a small water container that then overflows to a drain. That container has a tap on and is a free supply of distilled water for irons etc. It's pretty much always full this time of year but we sometimes run out in the summer.
Be interested to know how others record temperature and humidity over time ? I have a weatherstation "outdoor" unit in each garage which allows me to set an alarm and that works well but nothing that records historic temp and humidity.
200Plus Club said:
I have a meaco 8l rotary dessicant in my garage and sealed most of the gaps etc so it works more efficiently. The %rh stays exactly between 50-60% as it's on the middle of 3 settings. Constant drain to outside so no hassle. The drive motor went after 4 years and cost 24 quid from meaco and took an hour to fit myself. So much more convenient than the carcoon I had in my other garage.
Just got a DD8L for the garage. Still under test but at 50% setting (single fan) fills up tray in under a day. Am intending to external drain. Have it set up on a IP power switch with an iPhone app so I can power on/off remotely and see what wattage it consumes via my energy meter.Another vote for a carcoon here... Garages are deliberately drafty in order to ensure that fumes don't build up, and to stop them getting too damp. If you run a dehumidifier in one, you're basically trying to dehumidify the street.
Heating, weatherstrips etc will improve things vastly, but sealing it up in its own plastic tent will be the most efficient way to do it.
Heating, weatherstrips etc will improve things vastly, but sealing it up in its own plastic tent will be the most efficient way to do it.
donkmeister said:
Another vote for a carcoon here... Garages are deliberately drafty in order to ensure that fumes don't build up, and to stop them getting too damp. If you run a dehumidifier in one, you're basically trying to dehumidify the street.
Heating, weatherstrips etc will improve things vastly, but sealing it up in its own plastic tent will be the most efficient way to do it.
Nope, UK garages are drafty because in the UK (like most houses) they are generally built sub standard with no insulation and poor quality materials, contrast with Germany, similar climate totally different construction quality. You just need to retrofit them to the right standard or build them properly in the first place - the latter can be challenging because if you do put in plans to build a garage properly (cavity walls and insulation) the planners assume you are going to convert it in to a house and so become difficult. Heating, weatherstrips etc will improve things vastly, but sealing it up in its own plastic tent will be the most efficient way to do it.
I experimented with Carcoons and similar products internal and external before switching to dehumidifiers. The problem with the ventilation approach in our climate is when it's been cold for a few days and then we get some warm moist air as happens a few times a month thorough winter. The warm moist air is blown in and cools slightly - it can't then hold moisture so condenses on the coldest thing it can find (the car). I've seen this numerous times and it is basic physics and logic. If it is inside a sealed building or barn/warehouse it's not as bad as the air is slightly warmer and recirculated so less related to outside weather.
The only way to stop rust is to get humidity down (ideally 50% but formula is more complicated than that) and the best way to do that is dehumidify and the more heat the less you need to dehumidify.
There is one other option that can work well if you don't use the vehicle much, a Permabag, this is like a huge freezer bag so seals the car from the environment and you have a moisture absorbing desiccant inside but vehicle has to be bone dry when it goes in. They work well for stuff that isn't going to be disturbed (or if you don't have power) so I use them for long term storage of spares like engines.
There was a pretty decent topic on the Homes section about dehumidifiers being used in a garage:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
For this application compressor type dehumidifiers take a bad rap because people try and use machines that are basically designed for drying out your laundry inside your house, and then expect them to work in an unheated garage.
Desiccant dehumidifiers are not that efficient and consume a large amount of power compared the amount of dehumidification that they actually do, in the depths of winter (not really a thing in the UK with an average temp of 10 degrees) then they very well might be able to do the right amount of dehumidification required, but generally if it warms up, their capacity doe not increase and then they become out of their depth.
Anything "domestic" is not really suitable for a garage, and to top it off the performance figures/specifications supplied by the manufacturers are often complete rubbish.
Proper compressor driven dehumidifiers, which are designed from the ground up for garages, in UK climatic conditions might not be the least expensive option, but they will be the most efficient and most suitable method for garage dehumidification and will hopefully give you 20 years of service.
If anyone would like to discuss proper options, feel free to PM me.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
For this application compressor type dehumidifiers take a bad rap because people try and use machines that are basically designed for drying out your laundry inside your house, and then expect them to work in an unheated garage.
Desiccant dehumidifiers are not that efficient and consume a large amount of power compared the amount of dehumidification that they actually do, in the depths of winter (not really a thing in the UK with an average temp of 10 degrees) then they very well might be able to do the right amount of dehumidification required, but generally if it warms up, their capacity doe not increase and then they become out of their depth.
Anything "domestic" is not really suitable for a garage, and to top it off the performance figures/specifications supplied by the manufacturers are often complete rubbish.
Proper compressor driven dehumidifiers, which are designed from the ground up for garages, in UK climatic conditions might not be the least expensive option, but they will be the most efficient and most suitable method for garage dehumidification and will hopefully give you 20 years of service.
If anyone would like to discuss proper options, feel free to PM me.
After 2 week observation, my RH keep in between 59% and 66%.
Like some of you said, it made me feel like my dehumidifier is trying to dehumidify the street.
I have changed it to eco mode (saving more power), and keep running 24/7.
I predict it ends up £6xx-£7xx more on my annual electricity bill. *.*
May be a timer control plug for 8-12 hours setup is better way to control the cost.
In the meantime, I have bought the garage door insulation from weatherstops.co.uk, and would try to put them on and see any help.
Like some of you said, it made me feel like my dehumidifier is trying to dehumidify the street.
I have changed it to eco mode (saving more power), and keep running 24/7.
I predict it ends up £6xx-£7xx more on my annual electricity bill. *.*
May be a timer control plug for 8-12 hours setup is better way to control the cost.
In the meantime, I have bought the garage door insulation from weatherstops.co.uk, and would try to put them on and see any help.
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