Trailer Vented With Furnace On?

darsben1 wrote:

It could be said the additional moisture comes from the human body.

It could be said that the earth is flat. Doesn't make it true.

These 5 page sure are much to do about nothing. If the OP or his DW feels better venting some fresh air, open the window a little. Most TTs leak air like a sieve anyway.

myredracer wrote:
Water released by a human body is called "sensible" and "insensible" in the medical/scientific world. Sensible is what's released by a body in the form of feces and urine (aka pee & poo to RV-ers) and can be easily measured. "Insensible" is moisture released by the body from perspiration and respiration and cannot be easily measured. For the average adult in a "normal" temp. and humidity environment, the body releases around 40 ounces a day (5 cups per day) into the surrounding air from perspiration and respiration. In very high temps., a body can release as much as 8 cups an hour. In low humidity conditions, a body will release more moisture from respiration.

The lungs are part of a very complex gas exchange system and take in oxygen from the atmosphere and our body cells exchange that for carbon dioxide and water and expel it back into the atmosphere. Moisture in the air that is inhaled does not form part of the lung's gas exchange process and gets exhaled back out in the same amount.

If you have a dog, it will also release moisture into the air. For an adult human couple, you are looking at removing at least 10 cups a day plus whatever your pet does. That's a lotta water... Then there is moisture released into the inside air from cooking, washing dishes and showering and is hard to quantity. If all that moisture in the air inside a TT is not removed somehow, it's going to get into the structure and cabinetry and lead to rot and/or mold issues.

Thanks

dewey02 wrote:

captnjack wrote:
For those who blame the exhalation of moist air:
Don't we also INHALE? Isn't it the same air (assuming no ventilation)? Seems respiration would be a tossup as far as producing excess moisture.

Clearly a misunderstanding of the human body and how it functions.
Humans do not get the majority of their liquid requirements from breathing air, so the humidity intake into the lungs is NOT equal to the humidity expelled.
Do you not drink liquids?
Do you not eat foods? (which all contain water)
Where do you think that liquid goes? Bodily waste, perspiration, and exhalation.

Ya, myredracer got that explained a few moments before you posted. In a very nice and informative way.

.

Water released by a human body is called "sensible" and "insensible" in the medical/scientific world. Sensible is what's released by a body in the form of feces and urine (aka pee & poo to RV-ers) and can be easily measured. "Insensible" is moisture released by the body from perspiration and respiration and cannot be easily measured. For the average adult in a "normal" temp. and humidity environment, the body releases around 40 ounces a day (5 cups per day) into the surrounding air from perspiration and respiration. In very high temps., a body can release as much as 8 cups an hour. In low humidity conditions, a body will release more moisture from respiration.

The lungs are part of a very complex gas exchange system and take in oxygen from the atmosphere and our body cells exchange that for carbon dioxide and water and expel it back into the atmosphere. Moisture in the air that is inhaled does not form part of the lung's gas exchange process and gets exhaled back out in the same amount.

If you have a dog, it will also release moisture into the air. For an adult human couple, you are looking at removing at least 10 cups a day plus whatever your pet does. That's a lotta water... Then there is moisture released into the inside air from cooking, washing dishes and showering and is hard to quantity. If all that moisture in the air inside a TT is not removed somehow, it's going to get into the structure and cabinetry and lead to rot and/or mold issues.

For those who blame the exhalation of moist air:
Don't we also INHALE? Isn't it the same air (assuming no ventilation)? Seems respiration would be a tossup as far as producing excess moisture.

Some one says cold winter air is dry....hasn't lived in this part of the country where we can have high humidity levels and teen/single digit temps and 40 mph winds.

The mod mentioned the biggest source of humidity in a trailer and thats an open flame from the cooking stove.
Three way chili is popular around our house in the winter. A big pan of boiling water when cooking the Spaghetti has condensation dripping every where.

What works for keeping condensation out of a rv depends on several criteria such as.......
outside RH levels
inside RH levels
level of a units insulating values
double pane vs single pane windows
aluminum vs wood construction
wind speeds
outside temps
how much cooking is done on the propane stove
how much liquids is used when cooking

As my reply earlier says a vented trailer made a cold drafty camper and actually created more condensation.

The OP will have to use the different methods rv folks have found when fighting condensation in a particular unit in his particular part of the country.

mike-s wrote:

Chuck and Di wrote:

mike-s wrote:

darsben1 wrote:
RESPIRATION IS THE ANSWER to your question.

Bzzzzt. Wrong Answer. I'll claim that the OP breathes whether the furnace is on or not.

Mike, you need to get your buzzer fixed. Google is your friend.

People breathe out lots of moisture.

Tain't got nothing to do with nothing. I asked where the additional moisture came from.

It could be said the additional moisture comes from the human body. The moisture is in the lungs (simplistic model) it is expelled by your respiratory process. You lose moisture as you breathe. This lost has been estimated at 14-15 ounces (400 ML) of water per day. Perspiration will add more moisture up to another 14-15 ounces per day ( you may not even realize you are perspiring). At least that is what I learned in 2 years of taking Anatomy and Physiology at the Health Sciences college I attended. But my professor could have been wrong. The water was inside you and then becomes outside you so I believe that is additional water load into the air. Unless removed from the inside air IT WILL INCREASE THE RH inside the rig. Increased moisture in a given volume of air means increased Relative humidity. As the air is cooler near walls and windows in a rig the moisture will condense onto the cooler surfaces. Cooler air can hold less water so it has to go somewhere hence it condenses onto something cool.

So it summarize this thread.

DON'T breath in your trailer in the winter time if you are running the furnace. :B