Discussion
Does anyone use a dehumidifier in their garage to keep their Tiv free from damp?
I have an unheated timber garage with a bare concrete floor. I intend to paint the floor to stop moisture rising up through it, but I'm still concerned about condensation in there.
I went in the other day and the chassis was covered in condensation (although I did have some moisture getting in under the doors which I have now sorted out with a french drain). I use the car at weekends and every now and again during the week - and I will continue to do so over the winter.
I'm not sure whether just putting a greenhouse heater in there would do the job?
I know I would need a dehumdifier with hot gas defrost so it will work down to freezing point. Does anyone have any experience of these things they can share? How effective are they versus a small heater?
Thanks
Andy
I have an unheated timber garage with a bare concrete floor. I intend to paint the floor to stop moisture rising up through it, but I'm still concerned about condensation in there.
I went in the other day and the chassis was covered in condensation (although I did have some moisture getting in under the doors which I have now sorted out with a french drain). I use the car at weekends and every now and again during the week - and I will continue to do so over the winter.
I'm not sure whether just putting a greenhouse heater in there would do the job?
I know I would need a dehumdifier with hot gas defrost so it will work down to freezing point. Does anyone have any experience of these things they can share? How effective are they versus a small heater?
Thanks
Andy
The horse rug drier has been relegated to the greenhouse.
Two very wet and muddy horse rugs on a huge electric towel rail overnight in the garage = mega condensation = water running off in the garage.
TVR + rug drier = definite grounds for separation. Fortunately the greenhouse was a solution, so Melanie gets to stay
Two very wet and muddy horse rugs on a huge electric towel rail overnight in the garage = mega condensation = water running off in the garage.
TVR + rug drier = definite grounds for separation. Fortunately the greenhouse was a solution, so Melanie gets to stay
Well this thread seems to have developed over night....
I had a number of thoughts.
1) Timber garage is quite good as its natural insulating properties mean the temperature changes are fairly slow. More insulation will help
2) Untreated concrete floor is bad as moisture will always rise up through it. In my case a minor flood a few weeks ago means there is more moisture than normal. Flood defences now installed and moisture ingress at front dealt with.
3) The key to all of this is keeping the car, particularly the metal bits, at the same, or slightly higher temperature than the air in the garage. Problems arise when the temperature in the garage rises faster than the chassis, as moisture will then condense on the car.
4) I could heat the garage - which initially would cause condensation but once everything in the garage was the same temp (i.e. higher than the outside temp) it would do a reasonable job. My guess is that I would only need it a couple of degrees higher than outside - so a v small background heater on constantly may do the trick. The key is to keep it all constant though - so if I am in and out of the garage all the time this could be difficult.
Can someone explain to me why a paraffin heater will create moisture? I have seen some frost guard greenhouse 'sump' heaters that run for about 2 weeks on one fill and ony cost about £12 to buy.... seemed a cheaper option than electric.
5) Dehumdifiers work by creating an airflow and passing incoming air through a condenser and then expelling the drier air, at a slightly higher temperature than it entered. There are units on the market advertised for unheated areas such as garages, boats etc - with a facility to stop them freezing up in very cold weather. This seems to be the 'gold plated' solution. Although my garage is a bit draughty, it is not excessively so, so I will not be trying to dry out all the air in South Oxfordshire... The unit I am considering also has a humidity setting so that I can guarantee I won't dry out the leather and dash veneer.
I am coming to the conclusion the following may be the best solution:
1) paint the concrete floor with a waterproof paint
2) install some really low background heat (still don't know whether electric or paraffin is best?)
3) when I first put the car in there - particularly if I have just washed it or been out in the rain - run a dehumidifier in there for a day or so.
4) the rest of the time leave the heater on constant low heat, and use the dehumdifier in the house to stop mould forming on the shower room ceiling....
Added advantage would be my tools will stop rusting and the cardboard boxes in the garage (and my golf bag) will not be soggy and full of mildew.
Can anyone help on the paraffin v electric question?
P.S. For what it is worth, I don't think any car cover will control condensation - not unless the cover is an airtight 'bag' which you drive the car into. Otherwise air will flow under the car and condense on the chassis anyway. The only thing the breathable covers are good for is letting moisture out - so in theory you could put one on a damp car. Personally I'd always let the car dry first.
I had a number of thoughts.
1) Timber garage is quite good as its natural insulating properties mean the temperature changes are fairly slow. More insulation will help
2) Untreated concrete floor is bad as moisture will always rise up through it. In my case a minor flood a few weeks ago means there is more moisture than normal. Flood defences now installed and moisture ingress at front dealt with.
3) The key to all of this is keeping the car, particularly the metal bits, at the same, or slightly higher temperature than the air in the garage. Problems arise when the temperature in the garage rises faster than the chassis, as moisture will then condense on the car.
4) I could heat the garage - which initially would cause condensation but once everything in the garage was the same temp (i.e. higher than the outside temp) it would do a reasonable job. My guess is that I would only need it a couple of degrees higher than outside - so a v small background heater on constantly may do the trick. The key is to keep it all constant though - so if I am in and out of the garage all the time this could be difficult.
Can someone explain to me why a paraffin heater will create moisture? I have seen some frost guard greenhouse 'sump' heaters that run for about 2 weeks on one fill and ony cost about £12 to buy.... seemed a cheaper option than electric.
5) Dehumdifiers work by creating an airflow and passing incoming air through a condenser and then expelling the drier air, at a slightly higher temperature than it entered. There are units on the market advertised for unheated areas such as garages, boats etc - with a facility to stop them freezing up in very cold weather. This seems to be the 'gold plated' solution. Although my garage is a bit draughty, it is not excessively so, so I will not be trying to dry out all the air in South Oxfordshire... The unit I am considering also has a humidity setting so that I can guarantee I won't dry out the leather and dash veneer.
I am coming to the conclusion the following may be the best solution:
1) paint the concrete floor with a waterproof paint
2) install some really low background heat (still don't know whether electric or paraffin is best?)
3) when I first put the car in there - particularly if I have just washed it or been out in the rain - run a dehumidifier in there for a day or so.
4) the rest of the time leave the heater on constant low heat, and use the dehumdifier in the house to stop mould forming on the shower room ceiling....
Added advantage would be my tools will stop rusting and the cardboard boxes in the garage (and my golf bag) will not be soggy and full of mildew.
Can anyone help on the paraffin v electric question?
P.S. For what it is worth, I don't think any car cover will control condensation - not unless the cover is an airtight 'bag' which you drive the car into. Otherwise air will flow under the car and condense on the chassis anyway. The only thing the breathable covers are good for is letting moisture out - so in theory you could put one on a damp car. Personally I'd always let the car dry first.
icamm said: So not only do you create more moisture, and therefore rust, but you poison the air in the garage with CO2 so you can't enter it
Useful theft deterrent
...I appear to have a small pile of festering car thief corpses in my garage officer...
By the way - DIY and electrical stores are hopeless for this sort of electrical haeter. All they have is fan heaters and biggish oil filled radiators.
Man at the builders merchants thought I was a nutter when I bought some concrete paint and asked about frost protection heaters...
I've just left a 40w bulb on under mine until I get sorted. It looks a bit Max Power though!
I bought a dehumidifier today - a very nice Mitsubishi one with hot gas gefrost and a variable humidistat.
Bailey Air Conditioning next to Brize Norton deserve a mention. Not only were they very helpful, they turned out to be cheaper than any price I found on the web.
Finally, they were quite happy for me to leave with the unit without paying. They normally sell to the trade and are not geared up for credit cards and I had forgotten my cheque book. Not a problem they said - just pop a cheque in the post to us. Top people
Anyway - popped it in the garage - 80% relative humidity!! Not surprisingh given the car was soaking when I put it away last night, but not good at all - the new toy has some work to do (once it has sorted out the shower room.....).
Perhaps I need 2?!
On a different note Tube Heat calculated I would need a 3 kilowatt heater in the garage to keep the temp at 5-8%. That seemed a lot for a 5 metre x 6 metre garage - about 6' height at the sides rising to 9' at the apex. Sounds expensive to run? Again, top people -took some details, said they would phone back and sure enough they did. Twice.
Bailey Air Conditioning next to Brize Norton deserve a mention. Not only were they very helpful, they turned out to be cheaper than any price I found on the web.
Finally, they were quite happy for me to leave with the unit without paying. They normally sell to the trade and are not geared up for credit cards and I had forgotten my cheque book. Not a problem they said - just pop a cheque in the post to us. Top people
Anyway - popped it in the garage - 80% relative humidity!! Not surprisingh given the car was soaking when I put it away last night, but not good at all - the new toy has some work to do (once it has sorted out the shower room.....).
Perhaps I need 2?!
On a different note Tube Heat calculated I would need a 3 kilowatt heater in the garage to keep the temp at 5-8%. That seemed a lot for a 5 metre x 6 metre garage - about 6' height at the sides rising to 9' at the apex. Sounds expensive to run? Again, top people -took some details, said they would phone back and sure enough they did. Twice.
If you are using a dehumidifier in a cold environment (like an unheated or poorly heated garage), then you need one with 'hot gas defrost'.
The unit works by drawing air through a chiller, moisture condenses on the cold surface and runs into a tank, the dry air then passes through the hot end of the compressor and exits slightly warmer than when it entered the unit.
The problem is that in a cold environment the cold surface can freeze up, and the unit will stop working. Hot gas defrost means that it periodically stops and thaws itself out.
The B&Q £99 jobs tend not to have the defrost function.
Mine seems to remove up to 5 litres of moisture every 48-72 hours. Frightening. But then the felt on my garage roof leaks slightly and allows water to seep through to the roof timbers - so that doesn't help. I haven't had a dry weekend for ages to re-felt the roof.
Costs to run - I was told it was about 2p an hour - say £15 a month - if you have it on constantly. Not sure how accurate this is.
What I do is run the unit for a couple of days after putting the car in the garage wet. I find that once it is dry I don't have a problem with condensation on the chassis, so I don't bother with the de-humidifier.
Warm air holds more moisture than cold. As the air cools it cannot hold the water and it forms condensation. The problem is made worse if there are items (such as your car chassis) which are colder than the ambient air temperature, because condensation will form on them.
If you suddenly apply heat to the garage, the car will be cooler than the air and condensation will form on it. For this reason slow temp changes are best, with some form of background heat.
Steve - I would stick it out for a bit. In theory your car should be slightly warmer than everything else in the garage - so condensation should form on the colder surfaces (e.g. windows), rather than the car. Perhaps the chassis is not yet warmed by the heater?
The unit works by drawing air through a chiller, moisture condenses on the cold surface and runs into a tank, the dry air then passes through the hot end of the compressor and exits slightly warmer than when it entered the unit.
The problem is that in a cold environment the cold surface can freeze up, and the unit will stop working. Hot gas defrost means that it periodically stops and thaws itself out.
The B&Q £99 jobs tend not to have the defrost function.
Mine seems to remove up to 5 litres of moisture every 48-72 hours. Frightening. But then the felt on my garage roof leaks slightly and allows water to seep through to the roof timbers - so that doesn't help. I haven't had a dry weekend for ages to re-felt the roof.
Costs to run - I was told it was about 2p an hour - say £15 a month - if you have it on constantly. Not sure how accurate this is.
What I do is run the unit for a couple of days after putting the car in the garage wet. I find that once it is dry I don't have a problem with condensation on the chassis, so I don't bother with the de-humidifier.
Warm air holds more moisture than cold. As the air cools it cannot hold the water and it forms condensation. The problem is made worse if there are items (such as your car chassis) which are colder than the ambient air temperature, because condensation will form on them.
If you suddenly apply heat to the garage, the car will be cooler than the air and condensation will form on it. For this reason slow temp changes are best, with some form of background heat.
Steve - I would stick it out for a bit. In theory your car should be slightly warmer than everything else in the garage - so condensation should form on the colder surfaces (e.g. windows), rather than the car. Perhaps the chassis is not yet warmed by the heater?
What they say about relative humidity and temperature is correct.
But it seems to me this 'system' is simply heating and ventilating your garage.
Its not lying, but it does go out of its way to make it sound technically complex. It is simply a fan heater with an air intake connected outside the garage.
You could probably create the same effect by mounting a bathroom extractor fan in one of the windows. It would constantly change the air in the garage and this would certainly help.
But it seems to me this 'system' is simply heating and ventilating your garage.
Its not lying, but it does go out of its way to make it sound technically complex. It is simply a fan heater with an air intake connected outside the garage.
You could probably create the same effect by mounting a bathroom extractor fan in one of the windows. It would constantly change the air in the garage and this would certainly help.
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