Shop condensation!

[Skip Fix]

Dang I hate these cold fronts then warm moist fronts. The shop I have the cars is insulated metal building painted floors and when I was out yesterday setting lash on the a hot rod engine it was condensing on the spring retainers while I was working on it! And just since Wed it has that white aluminum spots all over the valve covers and intake from it.

The tractor rear tires are filled with water for ballast and one time last year they had so much condensation looked like someone threw a 5 gallon bucket of water on each one!

At 50'x70' 16' eaves- too big to "climate control" but was thinking some of those propane heater might dry the air out.
__________________

 

[billybudge]

I fully sympathise with you, I also am suffering with really bad condensation in my workshop, never had it so bad, this year seems to be the worse, and not sure why, tried a few different ways to heat the space, from oil filled radiators to gas heaters,also have really good ventilation, but still getting bad condensation, my main area is on the ceiling, constantly dripping onto everything, I am also interested in any ones input on heating the workshops,

 

[sberry]

What is the by product of burning propane?

 

[4 Ever-Fish N]

Same here in Deep East Texas. The main problem is the concrete floor.

 

[Showkey]

Dang I hate these cold fronts then warm moist fronts.

At 50'x70' 16' eaves- too big to "climate control" but was thinking some of those propane heater might dry the air out.
__________________

There are several dozen prior threads on this topic.........it’s impossible to control condensation without indoor climate controlled. You are at the mercy of every weather front. Not altogether different from trying to stop an ice tea glass from sweating on a hot humid day.

Invented propane heater would make things worse ....possible much worse.
A vented exhaust heater would make things better as it’s a step in the indoor climate control.

 

[Simplytodd]

I just asked this question last week. The final straw was mildew on the interior of my project car. I am going to try a few of those ceiling mounted electric heaters. My shop is 30x50 with 16’ saves so a little smaller than yours. They make larger versions than the two I am going to try. I will let you know how it goes.

 

[coljar]

What is the by product of burning propane?

Exactly.

Partition off the section to climate control with a vented furnace.

 

[GoodStuff]

Ceiling fans will help. Air movement is key


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[Showkey]

Ceiling fans will help. Air movement is key


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Nope......just mixes the air, does not change the relative humidity or the dew point of the air or items in the shop.

It would help condensation on windows in the warm home .......because it changes the temperature of the glass. Warming the glass window it will sweat less or stop sweating. Similar to the tea glass if it was no longer cold because of the warm breeze. The fan would also help warm object faster when the warm front comes through .......inverse things would cool quicker in cold weather making the condensation worse once the cold items were exposed to warm humid air.

If you have a mold issue........fans mix the air and mold spores over large areas.......making the problem worse.

 

[matt_i]

Nope......just mixes the air, does not change the relative humidity or the dew point of the air or items in the shop.

It would help condensation on windows in the warm home .......because it changes the temperature of the glass. Warming the glass window it will sweat less or stop sweating. Similar to the tea glass if it was no longer cold because of the warm breeze. The fan would also help warm object faster when the warm front comes through .......inverse things would cool quicker in cold weather making the condensation worse once the cold items were exposed to warm humid air.

If you have a mold issue........fans mix the air and mold spores over large areas.......making the problem worse.

I feel like if you are saying this you have never tried one. It is of course not a "concentrating device" like A/C or a dehumidifier. But....they work wonders in keeping condensation and mold off surfaces. I have them running, slowly, 24x7 in every shop bay and not because I like to waste the electricity....in my opinion the cheapest most reliable solution around to keep things clean that you don't want rusted from condensation.

It is imperative however to keep the space a "microclimate" that's not forced by the outside environment. Best way I know is to keep doors closed.

 

[finn]

Showkey is right. Moving air increases heat transfer rate, but doesn’t change relative humidity.

Increasing heat transfer rate brings surface temperature up to air temperature. Condensation won’t occur if there is no temperature differential.

 

[GoodStuff]

And thus my point. We all know the answer here, but if you’re not going to heat/cool the space then air movement is the next best solution in my mind


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[Glory]

Showkey is right. Moving air increases heat transfer rate, but doesn’t change relative humidity.

Increasing heat transfer rate brings surface temperature up to air temperature. Condensation won’t occur if there is no temperature differential.

Not saying you guys are wrong but...

When you call a company who specializes in rehabbing space that was water damaged, the first thing they do is roll out the fans. If the building is sealed, don’t you think the movement of air would impact the humidity inside the structure?

 

[Showkey]

Not saying you guys are wrong but...

When you call a company who specializes in rehabbing space that was water damaged, the first thing they do is roll out the fans. If the building is sealed, don’t you think the movement of air would impact the humidity inside the structure?

Yes you are correct ..........moving air will dry the floor or object quicker........but.........only if the air being moved is “drier” than the shop air. Air movement aids in evaporation. Little or no evaporation can occur if the air is saturated. Shop humidity problems start to be noticed when prolonged 70% plus levels are present.

If the shop is 70-80%-90% relative humidity no or little actual drying can actually occur. If the building is not sealed and the outside is saturated ( high humidity) .......then again nothing really changes except the electric bill.

The fans will help when the weather front changes as it normalizes the temperature change faster. Its part of the reason farmers leave the barn door open and old time wood barns were not sealed tight.

 

[Mikevolare]

propane heaters unvented, produce almost 1 gallon of moisture per 1 gallon of propane burned you need a vented appliance,or an sealed combustion appliance, electric heat pump or electric heater. Proper venting for moist air to leave, this will also bring in outside air to equalize pressure from vented air [leaving. i am no expert, but i just tested side wall venting to soffit and my moisture has dried up and not returned. this may create a heat loss of venting warm air, will have to test further to see how much is lost .

 

[pcmeiners]

"Increasing heat transfer rate brings surface temperature up to air temperature. Condensation won’t occur if there is no temperature differential."

Condensation does not occur due to temperature differential. it occurs due to air containing water vapor cooling to below it's dew point. It might be because an object such as a tool cools the air around it to the due point. The tools cools to a low temperature in the very early AM, then air circulation brings in warming moist air a couple hours later, tool being colder, cools the air around it and moisture condensing on it . Even if surfaces and air are exactly the same temperature, condensation will form once the temperature hits the dew point, no temperature differential is needed between surfaces and air temp.

 

[bdbecker]

Think about how much money you have invested in the tools, equipment, and vehicles stored in your shop. Buying a decent commercial/industrial grade dehumidifier (or two) might not be a bad idea.

 

[Showkey]

Think about how much money you have invested in the tools, equipment, and vehicles stored in your shop. Buying a decent commercial/industrial grade dehumidifier (or two) might not be a bad idea.

That may help but the building must be sealed and insulated ..........and.........even the cold temperature rated dehumidifier will not function well at temps below 50*.

The commercial dehumidifier units are not cheap to purchase or operate. A mini split in TX might make sense because it can heat and cool and will dehumidify at the same time. But it it a commitment to get the indoor climate in control.

 

[DenisG]

Condensation collects on cold metal when the temperature of the metal is below the dew point temperature. The steel acts like the cooling coils in a dehumidifier. Either raise the temperature of the steel above the dew point or eliminate the moisture in the air with a dehumidifier.

 

[finn]

"Increasing heat transfer rate brings surface temperature up to air temperature. Condensation won’t occur if there is no temperature differential."

Condensation does not occur due to temperature differential. it occurs due to air containing water vapor cooling to below it's dew point. It might be because an object such as a tool cools the air around it to the due point. The tools cools to a low temperature in the very early AM, then air circulation brings in warming moist air a couple hours later, tool being colder, cools the air around it and moisture condensing on it . Even if surfaces and air are exactly the same temperature, condensation will form once the temperature hits the dew point, no temperature differential is needed between surfaces and air temp.

I beg to differ with you. The temperature differential is exactly what cools the air to below the dew point when moisture laden air contacts a surface that is below the dew point of that moisture laden air.

I think maybe you’re saying the same thing, in a way, though.

If there’s no temperature differential between the surface and the air, there is no condensation.

Conversely, if there is a temperature differential but the surface, although colder than the air, is still above the dew point, there’s no condensation, either.

 

[Lonnies Performance]

I was having the same issue & on warm days I would open the garage door & the floor would condense moisture if the building was cold. My cars were water spotted frequently from the condensation dripping off the roof screws when it got cold overnight. Also, my building is twice the size of yours so I was extremely concerned with the cost of climate control.

Using a propane space heater was terrible & added to the condensation problem. Each gallon of fuel burned, adds about 1 gallon of water to the building.

I had 3 dehumidifiers running & they pulled a ton of water as long as it was 54 or hotter. Below this temperature, they dropped off a great deal in output. The biggest problem is they draw about 1000 watts power each.

I found that putting in a mini-split would both cool the air & dehumidify the building on hot days as well as give me a heat source when it was cold if I needed it. A single 30,000 BTU unit would remove more moisture for a similar power consumption than my 3 dehumidifiers.

It seemed like a good deal to add climate control. I'm not sure of your insulation quality, but I am R30 in walls & ceiling.

I installed 4 of these units, but typically run only 2 of them at a time. Running 2 of them 5hrs/day during the week (4-9pm) & 12hrs/day weekends (9am-9pm) to maintain 72 while I was working out there, cost about $90/month in the summer when it was 85-90 during the day.

Those same 2 units can keep it in the low-mid 60's when its 30deg outside for about $200/mo with the same run schedule. These costs are my total electric bill, not just the heat pumps. If you are of similar construction, you can possibly do so for about 1/2 of my costs above.

 

[isb cornbinder]

Dang I hate these cold fronts then warm moist fronts. The shop I have the cars is insulated metal building painted floors and when I was out yesterday setting lash on the a hot rod engine it was condensing on the spring retainers while I was working on it! And just since Wed it has that white aluminum spots all over the valve covers and intake from it.

The tractor rear tires are filled with water for ballast and one time last year they had so much condensation looked like someone threw a 5 gallon bucket of water on each one!

At 50'x70' 16' eaves- too big to "climate control" but was thinking some of those propane heater might dry the air out.
__________________

If the propane heater you are suggesting is one of the direct to air heater, it may not be your best choice. When these burners are operating they produce one gallon of moisture for every gallon of fuel burned.

 

[Showkey]

Condensation collects on cold metal when the temperature of the metal is below the dew point temperature. The steel acts like the cooling coils in a dehumidifier. Either raise the temperature of the steel above the dew point or eliminate the moisture in the air with a dehumidifier.

True ..........condensation maybe solved, condensation is just one of the symptoms ..........but........prolonged high relative humidity without condensation can still be a BIG problem. Warm moist air is cause for mold, mildew and funky smells....the kind we often get in Midwest basements.......that is where the dehumidifier is the cure.

 

[HC33]

Get big silica packets put them everywhere. The bigger the better. gunsafe companys sell huge ones.

 

[nsula_country]

Dang I hate these cold fronts then warm moist fronts. The shop I have the cars is insulated metal building painted floors and when I was out yesterday setting lash on the a hot rod engine it was condensing on the spring retainers while I was working on it! And just since Wed it has that white aluminum spots all over the valve covers and intake from it.

The tractor rear tires are filled with water for ballast and one time last year they had so much condensation looked like someone threw a 5 gallon bucket of water on each one!

At 50'x70' 16' eaves- too big to "climate control" but was thinking some of those propane heater might dry the air out.
__________________

I am climate controlling "tempering" a 40'x60' 17' eave building... 5 Ton Heat Pump. We are in the same region. You would need closer to 7.5 Ton to 10 Ton for your space. Systems over 5 Ton are 3P compressors though...

Also have 4, 60" Emerson warehouse ceiling fans "heat fan" HF1160BQ. Very impressive amount of air circulation. Dramatically helps with the large temp swings we have been having.

If using propane heater it needs to be a vented unit. A torpedo or salamander type will just pump in more moisture.

My tractor tires are sweating too.

CT

 

[pcmeiners]

"Get big silica packets put them everywhere. The bigger the better. gunsafe companys sell huge ones."

You must have access to some pretty huge silica packs, because it would require one the size of a dump truck, changed or regenerated often to keep the average garage condensation free..

"The Silica Gel, made from sodium silicate, is a highly porous substance that can absorb up to 40% of its own weight, which makes this the highest absorption capacity of any commercially used Desiccant. Most Silica Gel products can be reused by reactivating the Silica Gel contents (contact your Silica Gel manufacturer or retail partner for specific reactivation instructions for their products)."