I design and build my own incubators.

[NomoreCSIncubating]

Your are definitely right that you can't compare large commercial incubators to small hobby incubators. It's my understanding that one of the main reasons for increasing the humidity in large commercial incubators is to dissipate heat. During the later stage of incubation egg produce a lot of heat and the circulating air is actually cooling the eggs. Humid air conducts the transfer of heat more efficiently. With out it the egg would quickly overheat. Imaging how much heat is generated by a hundred thousand eggs. Could be why you have success at a slightly lower incubating temp. I have no problem incubating and hatching at a relatively constant humidity, though its difficult to get much lower than 40 in my climate.

Well I find that with a longer incubator that the air being blown by the fan cools down very fast and makes it harder to maintain a consistent temp inside the incubator where as if you are heating up water to be pushed by the fan it stays hotter longer for the bigger incubators and the moist air creates a buffer from the heating elements in the Styrofoam incubators.

My incubators I prefer to have the heat source come on at 97 and off at 99 but be able to maintain the temp as long as possible when the heat is off.

 

[HenOnAJuneBug]

Humid air conducts the transfer of heat more efficiently

It's actually the opposite because humid air has a slightly lower thermal conductivity than dry air. What water does is release heat as it evaporates.

 

[NomoreCSIncubating]

It's actually the opposite because humid air has a slightly lower thermal conductivity than dry air. What water does is release heat as it evaporates.

Water has to be heated first in order to evaporate to cause humidity inside the incubator! While that water is at that temperature it is pushed around the inside of the incubator until it cools off and slows down and condenses back in the bottom to be reheated to start the evaporation process all over again!

Dry heat can do exactly the same thing in a small enough area.

 

[HenOnAJuneBug]

Water has to be heated first in order to evaporate to cause humidity inside the incubator! While that water is at that temperature it is pushed around the inside of the incubator until it cools off and slows down and condenses back in the bottom to be reheated to start the evaporation process all over again!

Dry heat can do exactly the same thing in a small enough area.

Water vapor is not going to condense at the temperatures inside of an incubator. As the humidity goes up, evaporation slows, and vice versa. Air exchange with external air causes the humidity to decrease, if ambient humidity is lower.

 

[HatchCraft]

It's actually the opposite because humid air has a slightly lower thermal conductivity than dry air. What water does is release heat as it evaporates.

If you say so, I may have misphrased it . I'm no expert, but I pretty sure humid air has a high thermal capacitance and can absorb more heat which equals more heat transfer than dry air. I wasn't talking about evaporative cooling.Evaporation does have a cooling effect, but I was referring to water vapor not liquid water. Higher the humidity the lower the evaporation rate.

 

[BirdsBeesTrees]

If you say so, I may have misphrased it . I'm no expert, but I pretty sure humid air has a high thermal capacitance and can absorb more heat which equals more heat transfer than dry air. I wasn't talking about evaporative cooling.Evaporation does have a cooling effect, but I was referring to water vapor not liquid water. Higher the humidity the lower the evaporation rate.

I went to Texas I said I thought you said it was hot here? They said it's 100' I come back to Iowa. I think I'm dying, sweat rolling off of me. It's much hotter here! Its 80', humidity definitely makes it feel much hotter!

 

[NomoreCSIncubating]

Water vapor is not going to condense at the temperatures inside of an incubator. As the humidity goes up, evaporation slows, and vice versa. Air exchange with external air causes the humidity to decrease, if ambient humidity is lower.

Well know what I don't have to worry about that and not going to argue with you about it.

With my incubators I understand that when it is raining outside and depending on how much rain we get will effect the humidity inside the incubator.

With that said I can open up the incubator candle all the eggs and do what I need to do if the humidity was 21% it will only go up to 22% and it takes 5+" of rain to get the humidity up to 35% so I just never worry about humidity I know what it is going to be all the time.

 

[HenOnAJuneBug]

With that said I can open up the incubator candle all the eggs and do what I need to do if the humidity was 21% it will only go up to 22% and it takes 5+" of rain to get the humidity up to 35% so I just never worry about humidity I know what it is going to be all the time.

If you run at 22% your thermal conductivity is greater than at, let's say, 80%. Here's a graph that shows this. As temp and humidity increase thermal conductivity decreases, meaning less heat is imparted to the eggs, which is maybe why you can run at lower temps.

 

[NomoreCSIncubating]

If you run at 22% your thermal conductivity is greater than at, let's say, 80%. Here's a graph that shows this. As temp and humidity increase thermal conductivity decreases, meaning less heat is imparted to the eggs, which is maybe why you can run at lower temps.

Well also not running any water in my incubators allows them to be run outside in temps down to 32 degrees and still maintain incubator temp inside the incubator. I prefer that advantage.

 

[HenOnAJuneBug]

To give you an idea how humidity affects thermal conductivity (the ability to transfer heat energy), thermal conductivity is 0.029 at 20% humidity and 69 F temp. To get that same 0.029 at 30% humidity you'd have to raise the temp to 76-77 F.