OK, I’ve been using one of those 90,000 BTU turbo jet looking propane heaters for a few successful years now. But I’ve had it with how it makes everything sweat. The floor sweats, the wheels on the cars sweat, the brakes rust over, etc, etc. Is there a simple, non permanent solution that’ll heat the garage but in a dry manner? What’s the best route to go? Garage is 26’x36’.
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How to Avoid Sweat With Prooane Heater
- Thread starter galaxy
- Start date
Shiftless
Well-known member
OK, I’ve been using one of those 90,000 BTU turbo jet looking propane heaters for a few successful years now. But I’ve had it with how it makes everything sweat. The floor sweats, the wheels on the cars sweat, the brakes rust over, etc, etc. Is there a simple, non permanent solution that’ll heat the garage but in a dry manner? What’s the best route to go? Garage is 26’x36’.
The basic chemistry of burning propane and any other hydrocarbon fuel or even hydrogen, is that water vapor is one of the products of combustion. Once the relative humidity gets high enough, that vapor will condense on cooler objects.
The only cure is to change to a venting heater. Or go electric.
Adk Mike
Well-known member
Invest in a vented Modine Hotdawg. Mounts up out of the way and the moisture will be gone.
Moisture with an unvented unit it’s the nature of the beast.
Moisture with an unvented unit it’s the nature of the beast.
Using a 90kbtu vent free unit in an enclosed space is just not good, healthy or safe. Do you have CO alarms? The maximum size for an approved VF unit is 40kbtu. Get an approved vented heater. My suggestion would be a Rinnai EX-38.
HoosierBuddy
Well-known member
I agree with Shiftless, but there's another factor playing out here that makes the situation worse.
As you raise the temperature of air it can carry more water vapor as a percentage of the total mass. This is where the "dew point" comes into play.
When you raise the air temperature in a structure up, the air temperature rises faster than the surrounding temps. The air can carry more water vapor....right up until it comes into contact with a cold surface like a table saw, car, or concrete floor. That cold surface chills the air and the water vapor condenses.
I actually run into the same issue in my barn (which is unheated) on warm days where the air outside warms up, carries water into my barn and will rust up my tools which are still chilled if it was really cold night or similar.
Phil
As you raise the temperature of air it can carry more water vapor as a percentage of the total mass. This is where the "dew point" comes into play.
When you raise the air temperature in a structure up, the air temperature rises faster than the surrounding temps. The air can carry more water vapor....right up until it comes into contact with a cold surface like a table saw, car, or concrete floor. That cold surface chills the air and the water vapor condenses.
I actually run into the same issue in my barn (which is unheated) on warm days where the air outside warms up, carries water into my barn and will rust up my tools which are still chilled if it was really cold night or similar.
Phil
theoldwizard1
Well-known member
Propane is worse than other fuels !The basic chemistry of burning propane and any other hydrocarbon fuel or even hydrogen, is that water vapor is one of the products of combustion.
Invest in a vented Modine Hotdawg. Mounts up out of the way and the moisture will be gone.
Yep !
Thanks guys, and thanks for the unti suggestions. Something permanent and proper is on the list, but didn’t know if there was a way to combat the moisture through one more (this) winter. Which Modine do I want? Are there options? I take it those things run off a gas line from the line already coming into the house?
Jazz1
Well-known member
I put a fire on daily in garage even when not working just to keep temperature from getting too cold. The heat sink(floor) takes forever to warm up and I would end up with higher humidity.
finn
Well-known member
It doesn’t have to be Modine. There are probably a half dozen manufacturers offering similar vented propane and ng heaters for use in garages and outbuildings.
Shiftless
Well-known member
Is there a way to determine an appropriate size for heating a certain area? Multiple units, or just get one that’ll do the job? I assume these have fans/blowers?
It’s more complicated than just figuring the area. Outside temperatures, type of insulation, R values in walls and ceiling, how “tight” the building is, windows, doors, it all comes into play. You might find a local guy to do a heat loss calculation for you.
finn
Well-known member
That’s a small building, so a 45k or thereabouts should work.
Insulate the walls and ceiling, though.
Bigger isn’t better. An oversized heater will cycle constantly and you will have cold spots and drafts.
Insulate the walls and ceiling, though.
Bigger isn’t better. An oversized heater will cycle constantly and you will have cold spots and drafts.
3rdgendslmech
Well-known member
I have an 80K btu unit from Master? I think. Barn is 24x36 half the walls are insulated, ceiling is open. Vented ridge and soffit. I spent the coldest days in there with it running and didn't have any problems with condensation. I shut it down for the night and waited about 30 minutes and started to see if anything was sweating and I couldnt find anything, not even on the ceiling.
It’s more complicated than just figuring the area. Outside temperatures, type of insulation, R values in walls and ceiling, how “tight” the building is, windows, doors, it all comes into play. You might find a local guy to do a heat loss calculation for you.
I’m thinking I don’t quite need that much of a science project for my needs. Not saying you’re not most certainly correct, just not for this level of effort. I need the heat on rare occasions, maybe once a week, when in the garage doing garage stuff. This is not for a shop that’s used daily. Just need to pump some heat in there!
But since we’re here, it’s an attached garage. One and a half walls are insulated (up against the house), and the garage doors are insulated. As is, even on the coldest of nights (single digits), I don’t think I’ve ever seen it drop below freezing with no heater running. I just want something that’ll raise the temp to high 50’s low 60’s for short periods of time;3-4 hours at most. Ceiling fan does a fair to adequate job of controlling cold spots. But like I said, for how the space is used, I’m far from looking for perfection. I just want no sweating and humidity.