Why does humidity go up when I open incubator?

[jher77]

That makes sense thank you. So does this mean my readings haven't been accurate? I've had trouble getting the humidity reading up but the air cells seem small.

When you close the incubator back up and the air heats back up, the humidity will go back down. This chart shows why that happens:

Let's say you're fixing to incubate with room temperature air at 75F that is 35% RH. The chart says the dew point is 45. Now if you heat that same air up to 100F and find the dew point of 45 in that row, the RH will be 15%.

As far as the hygrometer being accurate, you would have to do the salt test to see.

 

[Lkase]

When you close the incubator back up and the air heats back up, the humidity will go back down. This chart shows why that happens:

Let's say you're fixing to incubate with room temperature air at 75F that is 35% RH. The chart says the dew point is 45. Now if you heat that same air up to 100F and find the dew point of 45 in that row, the RH will be 15%.

As far as the hygrometer being accurate, you would have to do the salt test to see.

This is so interesting! So if I have my temperature at 100 and my hydrometer is saying 25% does that mean that I am actually incubating at 63% humidity?

 

[jher77]

No. Your looking at it wrong. The chart tells you what your relative humidity will be if you heat or cool the same air. You can cross reference to see what happens to the humidity. I provided that to show why your humidity went up when you took the top off of the incubator.

If your temp is 100 and the hygrometer says 25%, that means your relative humidity for that temp is 25% but the dew point is 58F. If you unplug the incubator, leave it closed, and let it cool down to 75 degrees, then the relative humidity will now show 55% because if you find the dew point of 58F in the 75 degree row and look up at the top it is 55% relative humidity.

Hot air holds more water vapor than cool air. 50% RH at 100F is not the same as 50% RH at 75F. 50% relative humidity means the air is at 50% capacity of water vapor the air can hold at that temp.

 

[jher77]

Say temp is 65F and RH is 85%. Red box in that row.
Heat that same air up to 75F and now the RH is 60%.
Heat that same air up to 80F and now the RH is 52%.
Heat that same air up to 85F and now the RH is 42%.
Heat that same air up to 110F and now the RH is 20%. Hotter air holds more water vapor is why the percentage goes down.

 

[Lkase]

View attachment 2584478

Say temp is 65F and RH is 85%. Red box in that row.
Heat that same air up to 75F and now the RH is 60%.
Heat that same air up to 80F and now the RH is 52%.
Heat that same air up to 85F and now the RH is 42%.
Heat that same air up to 110F and now the RH is 20%. Hotter air holds more water vapor is why the percentage goes down.

Thank you! That makes so much sense. It reminds me of when I didn't have a garage. I'd try to figure out if my windshield would have ice in it in the morning by tracking the dew point! Anyway I am at day 19. Keeping the temp at 98.6 (forced air) humidity is staying at 22% even though I keep adding water. Room is 69 degrees at 52% humidity. Not sure what else to do. I have a shallow tray at the bottom with two sponges.

 

[jher77]

If you are trying to increase the humidity, you can move the water and sponges closer to the heat source. It will draw it up faster but run out of water faster too. Can you make the pan deeper so you don't have to open the incubator as much?

 

[EggSighted4Life]

This chart shows why that happens:

I was so disinterested during the public school phase of my life.. that this simple concept is just making sense and being useful in a very real way in my later 40's.. I bookmarked this page so that I can fully digest the information as to comprehend and retain it in order to share in the future of course. Thank you!

Thank you! That makes so much sense. It reminds me of when I didn't have a garage. I'd try to figure out if my windshield would have ice in it in the morning by tracking the dew point! Anyway I am at day 19. Keeping the temp at 98.6 (forced air) humidity is staying at 22% even though I keep adding water. Room is 69 degrees at 52% humidity. Not sure what else to do. I have a shallow tray at the bottom with two sponges.

My laughter is at your windshield thing.. here, here!

At 100.4 in forced air.. might expect hatch a little early.. a day perhaps.. 99.5 usually gives day 21 hatch.. 100.1 often gives day 20 hatch.. in my personal experience.

You humidity is effected by the surface area of you water not the depth. Add more surface area to increase humidity.. A wider container.. more ridges in the sponges MAYBE??.. these are quick brainstorm ideas..

 

[Lkase]

I think I'll open it quick enough to put a couple of wet sponges at the same level as the eggs. To add anything below I'd have to take the eggs out. I have plastic tubing ran to the outside at the water tray level. It is rainy here today so that may help! I might also turn in the humidifier in the room. You guys have been great. Thanks again.