Fighting condensation

[Slycox]

Evening,

Looking for thoughts and possible solutions to fight the excessive condensation I get when I run my heater. I run a propane torpedo style and have fought excessive condensation every time I run it. Would running a dehumidifier help or is there other options? My floor looks like I poured water on it after its been running for a while.

Thanks in advance.

 

[The Cobbler]

nature of the beast. propane is very damp heat.

 

[Showkey]

nature of the beast. propane is very damp heat.

Nature of the heater not the fuel.........
Any unvented heated with combustion will have the same issue no matter the fuel. More BTU more moisure produced.

 

[Autorotica]

How well insulated is your building?

Chris

 

[Shiftless]

Just like Showkey said, water vapor is unavoidable.
Chemists call it "product of combustion".
You also get lots of carbon dioxide.
Make sure to ventilate the space while you are using that heater. The manufacturer says so. So do most members of GJ.

The science says this...


C3H8 + 5 O2 -> 3 CO2 + 4 H2O

3 molecules of propane plus 5 molecules of oxygen from the air yields 3 molecules of carbon dioxide and 4 molecules of water. Plus HEAT!

44 pounds of propane burn to form 9 gallons of water.
So just 5 pounds of propane results in one gallon of water somewhere in your shop.

The water comes out as vapor because it's so hot, but in your shop, the moisture laden warm air cools off and water falls out on your floor (and your stationary tools, your rollaway toolbox and lots of other things you don't want to get wet and rusty.)

Yes, a dehumidifier would take away some of this water vapor but sounds like you should get a vented heater or go electric.

 

[Slycox]

Just like Showkey said, water vapor is unavoidable.
Chemists call it "product of combustion".
You also get lots of carbon dioxide.
Make sure to ventilate the space while you are using that heater. The manufacturer says so. So do most members of GJ.

The science says this...


C3H8 + 5 O2 -> 3 CO2 + 4 H2O

3 molecules of propane plus 5 molecules of oxygen from the air yields 3 molecules of carbon dioxide and 4 molecules of water. Plus HEAT!

44 pounds of propane burn to form 9 gallons of water.
So just 5 pounds of propane results in one gallon of water somewhere in your shop.

The water comes out as vapor because it's so hot, but in your shop, the moisture laden warm air cools off and water falls out on your floor (and your stationary tools, your rollaway toolbox and lots of other things you don't want to get wet and rusty.)

Yes, a dehumidifier would take away some of this water vapor but sounds like you should get a vented heater or go electric.

So your saying I shouldn't run in full blast in my 8x12 unvented shed?

I do ventilate, I try to keep the windows cracked and I have a very drafty door. And I don't do alot of stuff in there in the winter but when its -20F doing anything requires heat. For what I can afford and being I rent its the most economical heater IMO.

Thanks for the replies its helped my understanding a little bit. Hopefully next winter I will be somewhere else that I can insulate and heat better.

 

[Shiftless]

Slycox::
Wow! 20 below is extreme!
Are we talking Montana or North Dakota or Minnesota or what ?

I live in the San Francisco Bay Area so anything I say about winter weather here will just make guys hate me, so I will shut up.

 

[Slycox]

Slycox::
Wow! 20 below is extreme!
Are we talking Montana or North Dakota or Minnesota or what ?

I live in the San Francisco Bay Area so anything I say about winter weather here will just make guys hate me, so I will shut up.

North Dakota. We've been lucky so far this year, still getting above freezing for the most part.

Last winter I could get the garage to about 60 and shut off the heater and withing 15min drop a below freezing.

 

[Shiftless]

Dropping over 30 degrees in 15 min. is a real problem.
If you could seal the gaps around the window and door and put up some insulation, you could perhaps go with an electric heater and not have the condensation problem. Money spent on electricity would be offset by not buying propane. How many amps do you have available for heat? Serious heaters run on 220.

 

[Slycox]

Dropping over 30 degrees in 15 min. is a real problem.
If you could seal the gaps around the window and door and put up some insulation, you could perhaps go with an electric heater and not have the condensation problem. Money spent on electricity would be offset by not buying propane. How many amps do you have available for heat? Serious heaters run on 220.

Garage is on a 10amp breaker

I rent. I wasn't planning on being in this garage this winter and definitely not next winter. I can survive not bs'ing in there during the winter months just doing what I need that's it. If the house was able to accommodate our family better and I was going to be here long term I would insulate better and find a better heating source

 

[volaredon]

I am not renting (though it seems so as it seems I will never finish paying the mortgage) but the problem you describe is exactly why I put in a hanging unit heater in my garage.
I have also recently finished insulated the walls pretty heavily, haven't yet done the ceiling or attic space (I will eventually) but I had the same issue in my 30x36 garage.
built by me in 2006, but according to the inspector, "built like things were built in the 1950's"
In my garage everything would be soaked not so much while I had the torpedo full blast but like a couple hours after I shut it down..

I have the same problem in late winter when not running heat, as the temps just start to break above freezing again... hopefully keeping my new low temp stat set ~40*F all the time when I am not out there, will stop that, too.

 

[gungatim]

as stated, propane combustion products are co2 and water, so you can't get away from that unless you run a propane heater that is vented outside. easiest thing to do is run a dehumidifier (you can pickup used ones cheap at yard sales) and run that at the same time as the heater...

 

[Slycox]

as stated, propane combustion products are co2 and water, so you can't get away from that unless you run a propane heater that is vented outside. easiest thing to do is run a dehumidifier (you can pickup used ones cheap at yard sales) and run that at the same time as the heater...

Thats the plan, hopefully I won't have to run an extension cord from the house to the garage for one of them...

 

[volaredon]

I have a nat gas powered ventless wall mounted heater in my attached garage, and was told that these heaters have the same problem of producing moisture and condensation but so far, I have not noticed near the problem in that garage with condensation as I did in my detached garage with the torpedo. My parents have been running a ventless like this for at least 20 years in their attached garage with no moisture problems.

 

[Radix2]

Dehumidifiers need to run a long time to pass to air across the coils and dry it out. They also need decently warm temperatures so that the condensation on the coils does not freeze solid.

So a dehumidifier is unlikely to work in a a drafty garage with widely varying and cool temperatures and a moisture source that is condensing on cold floor surfaces. The cold floor is going to grab the moisture faster than the one foot square of the dehumidifier.

Unless you want one for something else, I wouldn't waste my money, put up with the way it is, and move along as soon as possible.

 

[Showkey]

Radix has it right ^^^^^^^^^^^^^^^^

The best dehumidifier ( $200 new) can run to 41* but they must run for long periods of time. In an unsealed envelope your throwing money out the window. Not likely to find a good one at the garage sale.........you will junk ones almost for free.

Also to say you have not problems with moisture..........try measuring it.
60-80 % in garage humidity is not uncommon, will go unnoticed until stuff starts happening. Winter humidity in the house might be 20-50% depending on temperature air exchange rate etc.

Your collector car does not need or like high humidity for prolonged periods of time.

How many posts are there where they ask "what's the black stuff on my garage rafters or under side of the roof sheeting."


Unventd heaters have other BIG issues ( discussed many times here) passing solvent fumes through the flame makes some nasty chemicals. Brake clean in one of the worst. But any burned solvent fume can be bad. I know safety is for sissies.

 

[Dick in Wisconsin]

The science says this...

C3H8 + 5 O2 -> 3 CO2 + 4 H2O

3 molecules of propane plus 5 molecules of oxygen from the air yields 3 molecules of carbon dioxide and 4 molecules of water. Plus HEAT!

So propane doesn't produce CO (carbon monoxide)? I thought ALL combustion produced carbon monoxide.

It seems that I see these propane powered torpedo heaters in closed up construction projects and they don't seem to be worried about carbon monoxide poisoning.

 

[BruceMc]

So propane doesn't produce CO (carbon monoxide)?

It can under the right conditions and often does -

http://www.propane101.com/carbonmonoxideandpropane.htm

 

[Shiftless]

It can under the right conditions and often does -

http://www.propane101.com/carbonmonoxideandpropane.htm

That is quite true.
The chemical equation I posted earlier assumes everything is in perfect adjustment and operating in lab conditions. Not the real world. My point was to remind all of us that the water produced by burning propane is completely unavoidable. Either vent it outdoors or let it build up in the garage. Ventilation is crucial !!!

I wonder if a standard issue household carbon monoxide detector would be a good idea there.
Although it might trigger at too low a threshold.

 

[brewchief]

Some thick clear plastic and a staple gun can cover the ceilings and walls and reduce the drafts.

An oversized heater probably isn't helping, something smaller that can run all the time may help slightly with the condensation and will in all probability make it much more comfortable to work in. One of the tank top radiant heaters might be a solution at a reasonable price.

 

[Slycox]

Some thick clear plastic and a staple gun can cover the ceilings and walls and reduce the drafts.

An oversized heater probably isn't helping, something smaller that can run all the time may help slightly with the condensation and will in all probability make it much more comfortable to work in. One of the tank top radiant heaters might be a solution at a reasonable price.

On a tight budget and with the cost of something that would be hard to reuse I don't think is wise. Looking for some cardboard or something along those lines. Need to seriously consider it.

I've used sunflower heaters in the past and they work ok, I chose the one I have for the forced air and able to adjust from 40k-80k btu. I can heat up relatively quick and dial back as needed. It just means I can't **** around for fun during the winter or do alot of extra projects. Just what's needed. Hopefully the next garage will be one I own and I can do more...just have to talk the wife into it..

 

[Dick in Wisconsin]

Looking for some cardboard or something along those lines. Need to seriously consider it.

What would you use the cardboard for? Insulation? If you have a condensation problem, won't the cardboard just get soaked with moisture?

You have a small space. The amount of 6mil poly that you need to seal your garage up shouldn't cost very much. You can always use a good stapler down the road. Get one that looks and works like a hammer.

 

[Showkey]

The sun flower infrared heaters does have merit for heating an immediate work area and the objects in that area like the people..........and does not heat the entire shop area.

I have spent a few hours warming in front of the "flower".......some of those hours ice fishing.

 

[Slycox]

What would you use the cardboard for? Insulation? If you have a condensation problem, won't the cardboard just get soaked with moisture?

You have a small space. The amount of 6mil poly that you need to seal your garage up shouldn't cost very much. You can always use a good stapler down the road. Get one that looks and works like a hammer.

Quite possibly it will get damp. But free vs $50 bucks...I can live with that.

 

[Slycox]

The sun flower infrared heaters does have merit for heating an immediate work area and the objects in that area like the people..........and does not heat the entire shop area.

I have spent a few hours warming in front of the "flower".......some of those hours ice fishing.

When I had sunflower style it was a single stall garage and it did a fair job, it was a cheap used heater. I got rid if it and went with the larger torpedo I have now to help with heating more of the area and what I'm working on.

 

[Shiftless]

Lining your whole workspace with flammable sheets of plastic or cardboard and using propane heaters sounds a bit dangerous. I know your winters are brutal but think about fire safety. Don't block off your ventilation and do keep a clear exit path.

 

[Autorotica]

Check out Harbor Freight Item#62313.

It is a 400/900 watt radiant heater. You could easily run 2 of them on low off of an extension with 1 on either side of you. Upside throw a bunch of light too.

Chris

P.s. An HVAC pro mentioned to me if you are running propane in an unheated garage you might want to leave an opening in the very peak insulation to give the moisture a place to LEAVE.

 

[Slycox]

Lining your whole workspace with flammable sheets of plastic or cardboard and using propane heaters sounds a bit dangerous. I know your winters are brutal but think about fire safety. Don't block off your ventilation and do keep a clear exit path.

Thanks for the concern and safety pointers. It would be to line the roof only to prevent the heat from going straight out the roof. I have a fan currently that blows down from the ceiling and even after a few minutes it blows warm air so I know I am loosing alot of heat up there.

I have 2 fire extinguishers already and my flammables are stored away from the heat source.

Check out Harbor Freight Item#62313.

It is a 400/900 watt radiant heater. You could easily run 2 of them on low off of an extension with 1 on either side of you. Upside throw a bunch of light too.

Chris

P.s. An HVAC pro mentioned to me if you are running propane in an unheated garage you might want to leave an opening in the very peak insulation to give the moisture a place to LEAVE.

The only problem I see with that would be that I would have to run extension cords from inside the house to inside the garage. I have tried to electric heaters and kept tripping the breaker...

Thanks for all the opinions and thoughts, many things to think about.



I have been offered a vent free wall unit to use. I am assuming it would present the same issue as my current torpedo style being it is not vented. Trying to decide of it would be worth it.

This is the style, not the exact one. http://www.northerntool.com/shop/tools/product_200649343_200649343

 

[Showkey]

^^^^^^^^^^^^^^
Same issue on condensation or producing water..........but........on the up side they are quiet compared to a torpedo.

 

[LS6 Tommy]

Nature of the heater not the fuel.........
Any unvented heated with combustion will have the same issue no matter the fuel. More BTU more moisure produced.

X2. If I run my kero fired torpedo when the garage is cold (<40*) I get condensation on every piece of metal in the garage. Good thing my LS6 is in a bag...

Tommy

 

[Autorotica]

The only problem I see with that would be that I would have to run extension cords from inside the house to inside the garage. I have tried to electric heaters and kept tripping the breaker...

You have most likely used 1500 watt resistance heaters in the past. Most hair dryers draw 1200-1400 watts.

The HF radiant heater on low only takes 400 watts.

Chris

 

[bry@n]

I have a nat gas powered ventless wall mounted heater in my attached garage, and was told that these heaters have the same problem of producing moisture and condensation but so far, I have not noticed near the problem in that garage with condensation as I did in my detached garage with the torpedo. My parents have been running a ventless like this for at least 20 years in their attached garage with no moisture problems.

I have a ventless NG heater attached to the wall and I get condensation. My entire garage is insulated, doors etc and I get it. I put it on and can hold temp for a while but my windows and garage windows get soaked.

I'm thinking of going electric. My sub panel is close and wouldn't be much of an issue.

 

[Shiftless]

Several members have said that unvented heaters burning gaseous fuels produce water. No way around that! You guys are absolutely right.
Here is a graphic to illustrate this point in case any of you were cutting
chemistry class in high school to hang out in the shop class.
Natural gas is mostly methane.
BBQ tanks are filled with Propane. Each propane molecule has 3 carbon atoms and 8 hydrogen atoms but you probably don't need to know that.

 

[Slycox]

I was homelearned myself, to busy hitting on the teacher...

 

[Showkey]

The horse is almost dead........but........example of a friends garage where they thought they did not have a moisure problem. Measured it was 60-75% humidity. Yes they have unvented heater. They did run a dehumidifier in the summer.

The mentioned they had funny stuff growing on rubber gloves, hoses and canvas etc. but had no rust issues that "were noticed." This was not everywhere or real noticeable until you start looking.

Mold and "funny growing stuff" is like rust it never sleeps.

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[Shiftless]

I bet the actual relative humidity was way higher. Like in the 90s.
I have a storage area prone to dampness. I have a dehumidifier for occasional use and a gauge to monitor the humidity. I keep it 75-80% max and I don't get mold or rust.
Dehumidifiers use a lot of power. Mine is about 600 watts so I don't run it all the time.

 

[Showkey]

Beating the related horse :

http://www.garagejournal.com/forum/showthread.php?t=312386&page=3